WorldWideScience

Sample records for carbon-rich supramolecular metallacycles

  1. Three's company: co-crystallization of a self-assembled S(4) metallacyclophane with two diastereomeric metallacycle intermediates.

    Science.gov (United States)

    Lindquist, Nathan R; Carter, Timothy G; Cangelosi, Virginia M; Zakharov, Lev N; Johnson, Darren W

    2010-05-28

    Three discrete supramolecular self-assembled arsenic(iii) complexes including an unusual S(4)-symmetric tetranuclear [As(4)L(2)Cl(4)] metallacyclophane and two diastereomeric cis/trans-[As(2)LCl(2)] metallacycle intermediates co-crystallize within a single crystal lattice.

  2. A Suite of Tetraphenylethylene-Based Discrete Organoplatinum(II) Metallacycles: Controllable Structure and Stoichiometry, Aggregation-Induced Emission, and Nitroaromatics Sensing.

    Science.gov (United States)

    Yan, Xuzhou; Wang, Haoze; Hauke, Cory E; Cook, Timothy R; Wang, Ming; Saha, Manik Lal; Zhou, Zhixuan; Zhang, Mingming; Li, Xiaopeng; Huang, Feihe; Stang, Peter J

    2015-12-09

    Materials that organize multiple functionally active sites, especially those with aggregation-induced emission (AIE) properties, are of growing interest due to their widespread applications. Despite promising early architectures, the fabrication and preparation of multiple AIEgens, such as multiple tetraphenylethylene (multi-TPE) units, in a single entity remain a big challenge due to the tedious covalent synthetic procedures often accompanying such preparations. Coordination-driven self-assembly is an alternative synthetic methodology with the potential to deliver multi-TPE architectures with light-emitting characteristics. Herein, we report the preparation of a new family of discrete multi-TPE metallacycles in which two pendant phenyl rings of the TPE units remain unused as a structural element, representing novel AIE-active metal-organic materials based on supramolecular coordination complex platforms. These metallacycles possess relatively high molar absorption coefficients but weak fluorescent emission under dilute conditions because of the ability of the untethered phenyl rings to undergo torsional motion as a non-radiative decay pathway. Upon molecular aggregation, the multi-TPE metallacycles show AIE-activity with markedly enhanced quantum yields. Moreover, on account of their AIE characteristics in the condensed state and ability to interact with electron-deficient substrates, the photophysics of these metallacycles is sensitive to the presence of nitroaromatics, motivating their use as sensors. This work represents a unification of themes including molecular self-assembly, AIE, and fluorescence sensing and establishes structure-property-application relationships of multi-TPE scaffolds. The fundamental knowledge obtained from the current research facilitates progress in the field of metal-organic materials, metal-coordination-induced emission, and fluorescent sensing.

  3. AgI -Induced Switching of DNA Binding Modes via Formation of a Supramolecular Metallacycle.

    Science.gov (United States)

    Basak, Shibaji; Léon, J Christian; Ferranco, Annaleizle; Sharma, Renu; Hebenbrock, Marian; Lough, Alan; Müller, Jens; Kraatz, Heinz-Bernhard

    2018-03-12

    The histidine derivative L1 of the DNA intercalator naphthalenediimide (NDI) forms a triangular Ag I complex (C2). The interactions of L1 and of C2 with DNA were studied by circular dichroism (CD) and UV/Vis spectroscopy and by viscosity studies. Different binding modes were observed for L1 and for C2, as the Ag I complex C2 is too large in size to act as an intercalator. If Ag I is added to the NDI molecule that is already intercalated into a duplex, higher order complexes are formed within the DNA duplex and cause disruptions in the helical duplex structure, which leads to a significant decrease in the characteristic CD features of B-DNA. Thus, via addition of a metal we show how a classic and well-known organic intercalator unit can be turned into a partial metallo insertor. We also show how electrochemical impedance spectroscopy (EIS) can be used to probe DNA binding modes on DNA films that are immobilized on gold surfaces. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Isotopic Hg in an Allende carbon-rich residue

    Science.gov (United States)

    Reed, G. W., Jr.; Jovanovic, S.

    1990-01-01

    A carbon-rich residue from Allende subjected to stepwise heating yielded two isotopically resolvable types of Hg: one with an (Hg-196)/(Hg-202) concentration ratio the same as terrestrial (monitor) Hg; the other enriched in Hg-196 relative to Hg-202 by about 60 percent. Hg with the 202 isotope enriched relative to 196, as is found in bulk Allende, was not observed. Whether the result of mass fractionation or nucleosynthesis, the distinct types of Hg entered different carrier phases and were not thermally mobilized since the accretion of the Allende parent body.

  5. Isotopic Hg in an Allende carbon-rich residue

    International Nuclear Information System (INIS)

    Reed, G.W. Jr.; Jovanovic, S.

    1990-01-01

    A carbon-rich residue from Allende subjected to stepwise heating yielded two isotopically resolvable types of Hg: one with an (Hg-196)/(Hg-202) concentration ratio the same as terrestrial (monitor) Hg; the other enriched in Hg-196 relative to Hg-202 by about 60 percent. Hg with the 202 isotope enriched relative to 196, as is found in bulk Allende, was not observed. Whether the result of mass fractionation or nucleosynthesis, the distinct types of Hg entered different carrier phases and were not thermally mobilized since the accretion of the Allende parent body. 9 refs

  6. Cyclopropenes in Metallacycle-Mediated Cross-Coupling with Alkynes: Convergent Synthesis of Highly Substituted Vinylcyclopropanes.

    Science.gov (United States)

    O'Rourke, Natasha F; Micalizio, Glenn C

    2016-03-18

    Stereodivergent metallacycle-mediated cross-coupling reactions are described for the synthesis of densely functionalized vinylcyclopropanes from the union of alkynes with cyclopropenes. Strategies explored include hydroxyl-directed and nondirected processes, with the latter of these delivering vinylcyclopropanes with exquisite levels of regio- and stereoselectivity. Challenges inherent to these coupling reactions include diastereoselectivity (with respect to the cyclopropene) and regioselectivity (with respect to both coupling partners).

  7. Mesoscopic self-organization of a self-assembled supramolecular rectangle on highly oriented pyrolytic graphite and Au(111) surfaces.

    Science.gov (United States)

    Gong, Jian-Ru; Wan, Li-Jun; Yuan, Qun-Hui; Bai, Chun-Li; Jude, Hershel; Stang, Peter J

    2005-01-25

    A self-assembled supramolecular metallacyclic rectangle was investigated with scanning tunneling microscopy on highly oriented pyrolytic graphite and Au(111) surfaces. The rectangles spontaneously adsorb on both surfaces and self-organize into well ordered adlayers. On highly oriented pyrolytic graphite, the long edge of the rectangle stands on the surface, forming a 2D molecular network. In contrast, the face of the rectangle lays flat on the Au(111) surface, forming linear chains. The structures and intramolecular features obtained through high-resolution scanning tunneling microscopy imaging are discussed.

  8. Widespread HCN maser emission in carbon-rich evolved stars

    Science.gov (United States)

    Menten, K. M.; Wyrowski, F.; Keller, D.; Kamiński, T.

    2018-05-01

    Context. HCN is a major constituent of the circumstellar envelopes of carbon-rich evolved stars, and rotational lines from within its vibrationally excited states probe parts of these regions closest to the stellar surface. A number of such lines are known to show maser action. Historically, in one of them, the 177 GHz J = 2 → 1 line in the l-doubled bending mode has been found to show relatively strong maser action, with results only published for a single object, the archetypical high-mass loss asymptotic giant branch (AGB) star IRC+10216. Aims: To examine how common 177 GHz HCN maser emission is, we conducted an exploratory survey for this line toward a select sample of carbon-rich asymptotic giant branch stars that are observable from the southern hemisphere. Methods: We used the Atacama Pathfinder Experiment 12 meter submillimeter Telescope (APEX) equipped with a new receiver to simultaneously observe three J = 2 → 1 HCN rotational transitions, the (0, 11c, 0) and (0, 11d, 0) l-doublet components, and the line from the (0,0,0) ground state. Results: The (0, 11c, 0) maser line is detected toward 11 of 13 observed sources, which all show emission in the (0,0,0) transition. In most of the sources, the peak intensity of the (0, 11c, 0) line rivals that of the (0,0,0) line; in two sources, it is even stronger. Except for the object with the highest mass-loss rate, IRC+10216, the (0, 11c, 0) line covers a smaller velocity range than the (0,0,0) line. The (0, 11d, 0) line, which is detected in four of the sources, is much weaker than the other two lines and covers a velocity range that is smaller yet, again except for IRC+10216. Compared to its first detection in 1989, the profile of the (0, 11c, 0) line observed toward IRC+10216 looks very different, and we also appear to see variability in the (0,0,0) line profile (at a much lower degree). Our limited information on temporal variabilitydisfavors a strong correlation of maser and stellar continuum flux

  9. Synergy in supramolecular chemistry

    CERN Document Server

    Nabeshima, Tatsuya

    2014-01-01

    Synergy and Cooperativity in Multi-metal Supramolecular Systems, T. NabeshimaHierarchically Assembled Titanium Helicates, Markus AlbrechtSupramolecular Hosts and Catalysts Formed by Self-assembly of Multinuclear Zinc Complexes in Aqueous Solution, Shin AokiSupramolecular Assemblies Based on Interionic Interactions, H. MaedaSupramolecular Synergy in the Formation and Function of Guanosine Quadruplexes, Jeffery T. DavisOn-Surface Chirality in Porous Self-Assembled Monolayers at Liquid-Solid Interface, Kazukuni Tahar

  10. Evidence for halo kinematics among cool carbon-rich dwarfs

    Science.gov (United States)

    Farihi, J.; Arendt, A. R.; Machado, H. S.; Whitehouse, L. J.

    2018-04-01

    This paper reports preliminary yet compelling kinematical inferences for N ≳ 600 carbon-rich dwarf stars that demonstrate around 30% to 60% are members of the Galactic halo. The study uses a spectroscopically and non-kinematically selected sample of stars from the SDSS, and cross-correlates these data with three proper motion catalogs based on Gaia DR1 astrometry to generate estimates of their 3-D space velocities. The fraction of stars with halo-like kinematics is roughly 30% for distances based on a limited number of parallax measurements, with the remainder dominated by the thick disk, but close to 60% of the sample lie below an old, metal-poor disk isochrone in reduced proper motion. An ancient population is consistent with an extrinsic origin for C/O >1 in cool dwarfs, where a fixed mass of carbon pollution more readily surmounts lower oxygen abundances, and with a lack of detectable ultraviolet-blue flux from younger white dwarf companions. For an initial stellar mass function that favors low-mass stars as in the Galactic disk, the dC stars are likely to be the dominant source of carbon-enhanced, metal-poor stars in the Galaxy.

  11. Frictional behavior of carbonate-rich sediments in subduction zones

    Science.gov (United States)

    Rabinowitz, H. S.; Savage, H. M.; Carpenter, B. M.; Collettini, C.

    2016-12-01

    Deformation in rocks and sediments is controlled by multiple mechanisms, each governed by its own pressure- (P), temperature- (T), and slip velocity- (v) dependent kinetics. Frictional behavior depends on which of these mechanisms are dominant, and, thus, varies with P, T, and v. Carbonates are a useful material with which to interrogate the PTv controls on friction due to the fact that a wide range of mechanisms can be easily accessed in the lab at geologically relevant conditions. In addition, carbonate-rich layers make up a significant component of subducting sediments around the world and may impact the frictional behavior of shallow subduction zones. In order to investigate the effect of carbonate subduction and the evolution of friction at subduction zone conditions, we conducted deformation experiments on input sediments for two subduction zones, the Hikurangi trench, New Zealand (ODP Site 1124) and the Peru trench (DSDP Site 321), which have carbonate/clay contents of 40/60 wt% and 80/20 wt%, respectively. Samples were saturated with distilled water mixed with 35g/l sea salt and deformed at room temperature. Experiments were conducted at σeff = 1-100 MPa and T = 20-100 °C with sliding velocities of 1-300 μm/s and hold times of 1-1000 s. We test the changes in velocity dependence and healing over these PT conditions to elucidate the frictional behavior of carbonates in subduction zone settings. The mechanical results are complemented by microstructural analysis. In lower stress experiments, there is no obvious shear localization; however, by 25 MPa, pervasive boundary-parallel shears become dominant, particularly in the Peru samples. Optical observations of these shear zones under cross-polarized light show evidence of plastic deformation (CPO development) while SEM-EDS observations indicate phase segregation in the boundary shears. Degree of microstructural localization appears to correspond with the trends observed in velocity-dependence. Our

  12. Regio- and Enantioselective N-Allylations of Imidazole, Benzimidazole, and Purine Heterocycles Catalyzed by Single-Component Metallacyclic Iridium Complexes

    Science.gov (United States)

    Stanley, Levi M.

    2010-01-01

    Highly regio- and enantioselective iridium-catalyzed N-allylations of benzimidazoles, imidazoles, and purines have been developed. N-Allylated benzimidazoles and imidazoles were isolated in high yields (up to 97%) with high branched-to-linear selectivity (up to 99:1) and enantioselectivity (up to 98% ee) from the reactions of benzimidazole and imidazole nucleophiles with unsymmetrical allylic carbonates in the presence of single component, ethylene-bound, metallacyclic iridium catalysts. N-Allylated purines were also obtained in high yields (up to 91%) with high N9:N7 selectivity (up to 96:4), high branched-to-linear selectivity (98:2), and high enantioselectivity (up to 98% ee) under similar conditions. The reactions encompass a range of benzimidazole, imidazole, and purine nucleophiles, as well as a variety of unsymmetrical aryl, heteroaryl, and aliphatic allylic carbonates. Competition experiments between common amine nucleophiles and the heterocyclic nitrogen nucleophiles studied in this work illustrate the effect of nucleophile pKa on the rate of iridium-catalyzed N-allylation reactions. Kinetic studies on the allylation of benzimidazole catalyzed by metallacyclic iridium-phosphoramidite complexes, in combination with studies on the deactivation of these catalysts in the presence of heterocyclic nucleophiles, provide insight into the effects of the structure of the phosphoramidite ligands on the stability of the metallacyclic catalysts. The data obtained from these studies has led to the development of N-allylations of benzimidazoles and imidazoles in the absence of an exogenous base. PMID:19480431

  13. Electrochemical study of lithium insertion into carbon-rich polymer-derived silicon carbonitride ceramics

    International Nuclear Information System (INIS)

    Kaspar, Jan; Mera, Gabriela; Nowak, Andrzej P.; Graczyk-Zajac, Magdalena; Riedel, Ralf

    2010-01-01

    This paper presents the lithium insertion into carbon-rich polymer-derived silicon carbonitride (SiCN) ceramic synthesized by the thermal treatment of poly(diphenylsilylcarbodiimide) at three temperatures, namely 1100, 1300, and 1700 o C under 0.1 MPa Ar atmosphere. At lower synthesis temperatures, the material is X-ray amorphous, while at 1700 o C, the SiCN ceramic partially crystallizes. Anode materials prepared from these carbon-rich SiCN ceramics without any fillers and conducting additives were characterized using cyclic voltammetry and chronopotentiometric charging/discharging. We found that the studied silicon carbonitride ceramics demonstrate a promising electrochemical behavior during lithium insertion/extraction in terms of capacity and cycling stability. The sample synthesized at 1300 o C exhibits a reversible capacity of 392 mAh g -1 . Our study confirms that carbon-rich SiCN phases are electrochemically active materials in terms of Li inter- and deintercalation.

  14. Supramolecular Photodimerization of Coumarins

    Directory of Open Access Journals (Sweden)

    Koichi Tanaka

    2012-02-01

    Full Text Available Stereoselective photodimerization of coumarin and its derivatives in supra-molecular systems is reviewed. The enantioselective photodimerization of coumarin and thiocoumarin in inclusion crystals with optically active host compounds is also described.

  15. Combining supramolecular chemistry with biology

    NARCIS (Netherlands)

    Uhlenheuer, D.A.; Petkau - Milroy, K.; Brunsveld, L.

    2010-01-01

    Supramolecular chemistry has primarily found its inspiration in biological molecules, such as proteins and lipids, and their interactions. Currently the supramolecular assembly of designed compounds can be controlled to great extent. This provides the opportunity to combine these synthetic

  16. Supramolecular luminescence from oligofluorenol-based supramolecular polymer semiconductors.

    Science.gov (United States)

    Zhang, Guang-Wei; Wang, Long; Xie, Ling-Hai; Lin, Jin-Yi; Huang, Wei

    2013-11-13

    Supramolecular luminescence stems from non-covalent exciton behaviors of active π-segments in supramolecular entities or aggregates via intermolecular forces. Herein, a π-conjugated oligofluorenol, containing self-complementary double hydrogen bonds, was synthesized using Suzuki coupling as a supramolecular semiconductor. Terfluorenol-based random supramolecular polymers were confirmed via concentration-dependent nuclear magnetic resonance (NMR) and dynamic light scattering (DLS). The photoluminescent spectra of the TFOH-1 solution exhibit a green emission band (g-band) at approximately ~520 nm with reversible features, as confirmed through titration experiments. Supramolecular luminescence of TFOH-1 thin films serves as robust evidence for the aggregates of g-band. Our results suggest that the presence of polyfluorene ketone defects is a sufficient condition, rather than a sufficient-necessary condition for the g-band. Supramolecular electroluminescence will push organic devices into the fields of supramolecular optoelectronics, spintronics, and mechatronics.

  17. Supramolecular Luminescence from Oligofluorenol-Based Supramolecular Polymer Semiconductors

    Directory of Open Access Journals (Sweden)

    Guang-Wei Zhang

    2013-11-01

    Full Text Available Supramolecular luminescence stems from non-covalent exciton behaviors of active π-segments in supramolecular entities or aggregates via intermolecular forces. Herein, a π-conjugated oligofluorenol, containing self-complementary double hydrogen bonds, was synthesized using Suzuki coupling as a supramolecular semiconductor. Terfluorenol-based random supramolecular polymers were confirmed via concentration-dependent nuclear magnetic resonance (NMR and dynamic light scattering (DLS. The photoluminescent spectra of the TFOH-1 solution exhibit a green emission band (g-band at approximately ~520 nm with reversible features, as confirmed through titration experiments. Supramolecular luminescence of TFOH-1 thin films serves as robust evidence for the aggregates of g-band. Our results suggest that the presence of polyfluorene ketone defects is a sufficient condition, rather than a sufficient-necessary condition for the g-band. Supramolecular electroluminescence will push organic devices into the fields of supramolecular optoelectronics, spintronics, and mechatronics.

  18. Carbohydrates in Supramolecular Chemistry.

    Science.gov (United States)

    Delbianco, Martina; Bharate, Priya; Varela-Aramburu, Silvia; Seeberger, Peter H

    2016-02-24

    Carbohydrates are involved in a variety of biological processes. The ability of sugars to form a large number of hydrogen bonds has made them important components for supramolecular chemistry. We discuss recent advances in the use of carbohydrates in supramolecular chemistry and reveal that carbohydrates are useful building blocks for the stabilization of complex architectures. Systems are presented according to the scaffold that supports the glyco-conjugate: organic macrocycles, dendrimers, nanomaterials, and polymers are considered. Glyco-conjugates can form host-guest complexes, and can self-assemble by using carbohydrate-carbohydrate interactions and other weak interactions such as π-π interactions. Finally, complex supramolecular architectures based on carbohydrate-protein interactions are discussed.

  19. Rheology of Supramolecular Polymers

    DEFF Research Database (Denmark)

    Shabbir, Aamir

    Supramolecular polymers are a broad class of materials that include all polymerscapable of associating via secondary interactions. These materials represent an emerging class of systems with superior versatility compared to classical polymers with applications in food stuff, coatings, cost...... efficient processes or biomedical areas. Design and development of supramolecular polymers using ionic, hydrogen bonding or transition metal complexes with tailored properties requires deep understanding of dynamics both in linear and non-linear deformations. While linear rheology is important to understand...... the dynamics under equilibrium conditions, extensional rheology is relevant during the processing or in the usage of polymers utilizing supramolecular associations for example, acrylic based pressure sensitive adhesives are subjected to extensional deformations during the peeling where strain hardening...

  20. Magnetism: a supramolecular function

    International Nuclear Information System (INIS)

    Decurtins, S.; Pellaux, R.; Schmalle, H.W.

    1996-01-01

    The field of molecule-based magnetism has developed tremendously in the last few years. Two different extended molecular - hence supramolecular -systems are presented. The Prussian-blue analogues show some of the highest magnetic ordering temperature of any class of molecular magnets, T c = 315 K, whereas the class of transition-metal oxalate-bridged compounds exhibits a diversity of magnetic phenomena. Especially for the latter compounds, the elastic neutron scattering technique has successfully been proven to trace the magnetic structure of these supramolecular and chiral compounds. (author) 18 figs., 25 refs

  1. Hydrogen bonded supramolecular materials

    CERN Document Server

    Li, Zhan-Ting

    2015-01-01

    This book is an up-to-date text covering topics in utilizing hydrogen bonding for constructing functional architectures and supramolecular materials. The first chapter addresses the control of photo-induced electron and energy transfer. The second chapter summarizes the formation of nano-porous materials. The following two chapters introduce self-assembled gels, many of which exhibit unique functions. Other chapters cover the advances in supramolecular liquid crystals and the versatility of hydrogen bonding in tuning/improving the properties and performance of materials. This book is designed

  2. Magnetism: a supramolecular function

    Energy Technology Data Exchange (ETDEWEB)

    Decurtins, S; Pellaux, R; Schmalle, H W [Zurich Univ., Inst. fuer Anorganische Chemie, Zurich (Switzerland)

    1996-11-01

    The field of molecule-based magnetism has developed tremendously in the last few years. Two different extended molecular - hence supramolecular -systems are presented. The Prussian-blue analogues show some of the highest magnetic ordering temperature of any class of molecular magnets, T{sub c} = 315 K, whereas the class of transition-metal oxalate-bridged compounds exhibits a diversity of magnetic phenomena. Especially for the latter compounds, the elastic neutron scattering technique has successfully been proven to trace the magnetic structure of these supramolecular and chiral compounds. (author) 18 figs., 25 refs.

  3. MOLECULAR LINE OBSERVATIONS OF THE CARBON-RICH CIRCUMSTELLAR ENVELOPE CIT 6 AT 7 mm WAVELENGTHS

    Energy Technology Data Exchange (ETDEWEB)

    Chau, Wayne; Zhang Yong; Nakashima, Jun-ichi; Kwok, Sun [Department of Physics, University of Hong Kong (Hong Kong); Deguchi, Shuji [Nobeyama Radio Observatory, National Astronomical Observatory, Minamimaki, Minamisaku, Nagano 384-1305 (Japan)

    2012-11-20

    We present a {lambda}7 mm spectral line survey of the carbon-rich circumstellar envelope (CSE) CIT 6 using the 45 m telescope at the Nobeyama Radio Observatory. A total of 25 spectral features belonging to five molecular species (HC{sub 3}N, HC{sub 5}N, HC{sub 7}N, SiO, and CS) are detected, enabling us to investigate the chemistry of cyanopolyyne chains. The line strengths are compared with those of the proto-typical carbon-rich CSE IRC+10216. The results show that the cyanopolyyne molecules are enhanced in CIT 6, suggesting that it is more evolved than IRC+10216. In order to investigate the structure of CIT 6, we have constructed a three-dimensional spatiokinematic model. By comparing the observed line profiles with the models, we conclude that this envelope is asymmetric and is composed of several incomplete shells.

  4. Estimating dust production rate of carbon-rich stars in the Small Magellanic Cloud

    Science.gov (United States)

    Nanni, A.; Marigo, P.; Groenewegen, M. A. T.; Aringer, B.; Pastorelli, G.; Rubele, S.; Girardi, L.; Bressan, A.; Bladh, S.

    We compute a grid of spectra describing dusty Circumstellar Envelopes of Thermally Pulsing Asymptotic Giant Branch carbon-rich stars by employing a physically grounded description for dust growth. The optical constants for carbon dust have been selected in order to reproduce simultaneously the most important color-color diagrams in the Near and Mid Infrared bands. We fit the Spectral Energy Distribution of ≈2000 carbon-rich in the Small Magellanic Cloud and we compute their total dust production rate. We compare our results with the ones in the literature. Different choices of the dust-to-gas ratio and outflow expansion velocity adopted in different works, yield, in some cases, a total dust budget about three times lower than the one derived from our scheme, with the same optical data set for carbon dust.

  5. Estimation of niobium, tantalum and zirconium in a carbonate rich ore

    International Nuclear Information System (INIS)

    Navale, A.S.; Venkatakrishnan, R.R.; Sreenivas, T.

    2013-01-01

    A simple method using ICP-OES for estimation of tantalum, niobium and zirconium in a carbonate rich matrix is described. The sample is boiled with 10% v/v hydrochloric acid for 15 min and filtered. The residue is fused with ammonium bifluoride-ammonium sulphate flux and the melt is leached with water. Nb, Ta and Zr are estimated in the water leach by ICP-OES. (author)

  6. Supramolecular fluorene based materials

    NARCIS (Netherlands)

    Abbel, R.J.

    2008-01-01

    This thesis describes the use of noncovalent interactions in order to manipulate and control the self-assembly and morphology of electroactive fluorene-based materials. The supramolecular arrangement of p-conjugated polymers and oligomers can strongly influence their electronic and photophysical

  7. Supramolecular tunneling junctions

    NARCIS (Netherlands)

    Wimbush, K.S.

    2012-01-01

    In this study a variety of supramolecular tunneling junctions were created. The basis of these junctions was a self-assembled monolayer of heptathioether functionalized ß-cyclodextrin (ßCD) formed on an ultra-flat Au surface, i.e., the bottom electrode. This gave a well-defined hexagonally packed

  8. Supramolecular systems chemistry

    NARCIS (Netherlands)

    Mattia, Elio; Otto, Sijbren

    The field of supramolecular chemistry focuses on the non-covalent interactions between molecules that give rise to molecular recognition and self-assembly processes. Since most non-covalent interactions are relatively weak and form and break without significant activation barriers, many

  9. Applications of supramolecular chemistry

    CERN Document Server

    Schneider, Hans-Jörg

    2012-01-01

    ""The time is ripe for the present volume, which gathers thorough presentations of the numerous actually realized or potentially accessible applications of supramolecular chemistry by a number of the leading figures in the field. The variety of topics covered is witness to the diversity of the approaches and the areas of implementation…a broad and timely panorama of the field assembling an eminent roster of contributors.""-Jean-Marie Lehn, 1987 Noble Prize Winner in Chemistry

  10. Supramolecular fluorene based materials

    OpenAIRE

    Abbel, R.J.

    2008-01-01

    This thesis describes the use of noncovalent interactions in order to manipulate and control the self-assembly and morphology of electroactive fluorene-based materials. The supramolecular arrangement of p-conjugated polymers and oligomers can strongly influence their electronic and photophysical properties. Therefore, a detailed understanding of such organisation processes is essential for the optimisation of the performance of these materials as applied in optoelectronic devices. In order to...

  11. RIR MAPLE procedure for deposition of carbon rich Si/C/H films

    International Nuclear Information System (INIS)

    Dřínek, Vladislav; Strašák, Tomáš; Novotný, Filip; Fajgar, Radek; Bastl, Zdeněk

    2014-01-01

    We applied the resonant infrared matrix assisted pulsed laser evaporation (RIR MAPLE) technique to demonstrate a new approach to a controlled deposition of carbon rich amorphous Si/C/H film. In absence of radicals and accelerated species commonly generated in PECVD and sputtering setups, the RIR MAPLE method does not decompose precursor molecules. Moreover, unlike the standard MAPLE procedure, in which solvent molecules absorb laser energy from excimer or near infrared lasers, we applied the pulsed TEA CO 2 laser to excite the dendrimer precursor molecules in a frozen target. In this manner we achieved just cross-linking of the starting precursor on substrates and the deposition of carbon rich Si/C/H film. The film was analyzed by Fourier Transformed Infrared (FTIR), UV/VIS, Raman and X-ray Photoelectron (XPS) spectroscopy and Atomic Force Microscopy (AFM) technique. According to analyses the film retained the precursor elemental composition free of graphitic (sp 2 ) clusters. In course of reaction only the peripheral allyl groups containing C=C bonds were opened to achieve cross-linking. Whereas annealing to 300 °C was necessary for the elimination of =C–H 1 , 2 bonds in the films prepared at 200 °C, those bonds vanished completely for the films prepared at substrate temperature 255 °C. The film posseses a smooth surface with root mean square (RMS) parameter up to 10 nm within scanned distance 2.5 μm.

  12. RIR MAPLE procedure for deposition of carbon rich Si/C/H films

    Energy Technology Data Exchange (ETDEWEB)

    Dřínek, Vladislav, E-mail: drinek@icpf.cas.cz [Institute of Chemical Process Fundamentals of the ASCR, v. v. i., Rozvojova 135, 165 02 Prague 6 (Czech Republic); Strašák, Tomáš [Institute of Chemical Process Fundamentals of the ASCR, v. v. i., Rozvojova 135, 165 02 Prague 6 (Czech Republic); Novotný, Filip [Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University, 115 19 Prague (Czech Republic); Fajgar, Radek [Institute of Chemical Process Fundamentals of the ASCR, v. v. i., Rozvojova 135, 165 02 Prague 6 (Czech Republic); Bastl, Zdeněk [J. Heyrovsky Institute of Physical Chemistry of the ASCR, v. v. i., Dolejškova 2155/3, 182 23 Prague 8 (Czech Republic)

    2014-02-15

    We applied the resonant infrared matrix assisted pulsed laser evaporation (RIR MAPLE) technique to demonstrate a new approach to a controlled deposition of carbon rich amorphous Si/C/H film. In absence of radicals and accelerated species commonly generated in PECVD and sputtering setups, the RIR MAPLE method does not decompose precursor molecules. Moreover, unlike the standard MAPLE procedure, in which solvent molecules absorb laser energy from excimer or near infrared lasers, we applied the pulsed TEA CO{sub 2} laser to excite the dendrimer precursor molecules in a frozen target. In this manner we achieved just cross-linking of the starting precursor on substrates and the deposition of carbon rich Si/C/H film. The film was analyzed by Fourier Transformed Infrared (FTIR), UV/VIS, Raman and X-ray Photoelectron (XPS) spectroscopy and Atomic Force Microscopy (AFM) technique. According to analyses the film retained the precursor elemental composition free of graphitic (sp{sup 2}) clusters. In course of reaction only the peripheral allyl groups containing C=C bonds were opened to achieve cross-linking. Whereas annealing to 300 °C was necessary for the elimination of =C–H{sub 1}, {sub 2} bonds in the films prepared at 200 °C, those bonds vanished completely for the films prepared at substrate temperature 255 °C. The film posseses a smooth surface with root mean square (RMS) parameter up to 10 nm within scanned distance 2.5 μm.

  13. Synthesis and characterization of hafnium carbide microcrystal chains with a carbon-rich shell via CVD

    International Nuclear Information System (INIS)

    Tian, Song; Li, Hejun; Zhang, Yulei; Liu, Sen; Fu, Yangxi; Li, Yixian; Qiang, Xinfa

    2013-01-01

    Graphical abstract: Novel HfC microcrystal chains have been synthesized via a catalyst-assisted chemical vapor deposition process. SEM results show the chains have a periodically changing diameter and a nanoscale sharpening tip. Analysis of TEM/SAED/EELS/EDX data shows the single-crystal chains grow along a [0 0 1] direction and consist of a HfC core and a thin carbon-rich shell with embedded HfC nanocrystallites surrounding the core. This work achieves the controllable preparation of nanoscale HfC sharpening tips for application as a point electron emission source and facilitates the application of HfC ultrafast laser-triggered tips in attosecond science. Highlights: •HfC microcrystal chains were synthesized by a catalyst-assisted CVD. •The chains grow along a [0 0 1] direction and have a periodically changing diameter. •Single-crystal HfC core is sheathed by a thin carbon-rich shell. •A growth mechanism model is proposed to explain the growth of microcrystal chians. •This work achieves the controllable preparation of nanoscale HfC sharpening tips. -- Abstract: Novel hafnium carbide (HfC) microcrystal chains, with a periodically changing diameter and a nanoscale sharpening tip at the chain end, have been synthesized via a catalyst-assisted chemical vapor deposition (CVD) process. The as-synthesized chains with many octahedral microcrystals have diameters of between several hundreds of nm and 6 μm and lengths of ∼500 μm. TEM diffraction studies show that the chains are single-crystalline HfC and preferentially grow along a [0 0 1] crystal orientation. TEM/EELS/EDX analysis proves the chains are composed of a HfC core and a thin (several tens of nm to 100 nm) carbon-rich shell with the embedded HfC nanocrystallites (typically below 10 nm) surrounding the core. The growth mechanism model for the chains based on the vapor–liquid–solid process, the vapor–solid process, and the HfC crystal growth characteristics is discussed

  14. Self-assembled copper(II) metallacycles derived from asymmetric Schiff base ligands: efficient hosts for ADP/ATP in phosphate buffer.

    Science.gov (United States)

    Kumar, Amit; Pandey, Rampal; Kumar, Ashish; Gupta, Rakesh Kumar; Dubey, Mrigendra; Mohammed, Akbar; Mobin, Shaikh M; Pandey, Daya Shankar

    2015-10-21

    Novel asymmetric Schiff base ligands 2-{[3-(3-hydroxy-1-methyl-but-2-enylideneamino)-2,4,6-trimethylphenylimino]-methyl}-phenol (H2L(1)) and 1-{[3-(3-hydroxy-1-methyl-but-2-enylideneamino)-2,4,6-trimethylphenylimino]-methyl}-naphthalen-2-ol (H2L(2)) possessing dissimilar N,O-chelating sites and copper(ii) metallacycles (CuL(1))4 (1) and (CuL(2))4 (2) based on these ligands have been described. The ligands and complexes have been thoroughly characterized by satisfactory elemental analyses, and spectral (IR, (1)H, (13)C NMR, ESI-MS, UV/vis) and electrochemical studies. Structures of H2L(2) and 1 have been unambiguously determined by X-ray single crystal analyses. The crystal structure of H2L(2) revealed the presence of two distinct N,O-chelating sites on dissimilar cores (naphthalene and β-ketoaminato groups) offering a diverse coordination environment. Metallacycles 1 and 2 having a cavity created by four Cu(ii) centres coordinated in a homo- and heteroleptic fashion with respective ligands act as efficient hosts for adenosine-5'-diphosphate (ADP) and adenosine-5'-triphosphate (ATP) respectively, over other nucleoside polyphosphates (NPPs). The disparate sensitivity of these metallacycles toward ADP and ATP has been attributed to the size of the ligands assuming diverse dimensions and spatial orientations. These are attuned for π-π stacking and electrostatic interactions suitable for different guest molecules under analogous conditions, metallacycle 1 offers better orientation for ADP, while 2 for ATP. The mechanism of the host-guest interaction has been investigated by spectral and electrochemical studies and supported by molecular docking studies.

  15. [Supramolecular Agents for Theranostics].

    Science.gov (United States)

    Deyev, S M; Lebedenko, E N

    2015-01-01

    This mini-review summarizes recent data obtained in the process of creation of a versatile module platform suitable for construction of supramolecular theranostic agents. As an example, we consider multifunctional hybrid agents for imaging and elimination of cancer cells. The use of an adapter protein system barnase:barstar for producing targeted multifunctional hybrid structures on the basis of highly specific peptides and mini-antibodies as addressing modules and recombinant proteins and/or nanoparticles of different nature (quantum dots, nanogold, magnetic nanoparticles, nanodiamonds, upconverting nanophosphores, polymer nanoparticles) as agents visualizing and damaging cancer cells is described. New perspectives for creation of selective and highly effective compounds for theranostics and personified medicine are contemplated.

  16. CARBON-RICH GIANT PLANETS: ATMOSPHERIC CHEMISTRY, THERMAL INVERSIONS, SPECTRA, AND FORMATION CONDITIONS

    Energy Technology Data Exchange (ETDEWEB)

    Madhusudhan, Nikku [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Mousis, Olivier [Institut UTINAM, CNRS-UMR 6213, Observatoire de Besancon, BP 1615, F-25010 Besancon Cedex (France); Johnson, Torrence V. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Lunine, Jonathan I., E-mail: nmadhu@astro.princeton.edu [Department of Astronomy, Cornell University, Ithaca, NY 14853 (United States)

    2011-12-20

    The recent inference of a carbon-rich atmosphere, with C/O {>=} 1, in the hot Jupiter WASP-12b motivates the exotic new class of carbon-rich planets (CRPs). We report a detailed study of the atmospheric chemistry and spectroscopic signatures of carbon-rich giant (CRG) planets, the possibility of thermal inversions in their atmospheres, the compositions of icy planetesimals required for their formation via core accretion, and the apportionment of ices, rock, and volatiles in their envelopes. Our results show that CRG atmospheres probe a unique region in composition space, especially at high temperature (T). For atmospheres with C/O {>=} 1, and T {approx}> 1400 K in the observable atmosphere, most of the oxygen is bound up in CO, while H{sub 2}O is depleted and CH{sub 4} is enhanced by up to two or three orders of magnitude each, compared to equilibrium compositions with solar abundances (C/O = 0.54). These differences in the spectroscopically dominant species for the different C/O ratios cause equally distinct observable signatures in the spectra. As such, highly irradiated transiting giant exoplanets form ideal candidates to estimate atmospheric C/O ratios and to search for CRPs. We also find that the C/O ratio strongly affects the abundances of TiO and VO, which have been suggested to cause thermal inversions in highly irradiated hot Jupiter atmospheres. A C/O = 1 yields TiO and VO abundances of {approx}100 times lower than those obtained with equilibrium chemistry assuming solar abundances, at P {approx} 1 bar. Such a depletion is adequate to rule out thermal inversions due to TiO/VO even in the most highly irradiated hot Jupiters, such as WASP-12b. We estimate the compositions of the protoplanetary disk, the planetesimals, and the envelope of WASP-12b, and the mass of ices dissolved in the envelope, based on the observed atmospheric abundances. Adopting stellar abundances (C/O = 0.44) for the primordial disk composition and low-temperature formation conditions

  17. Preservation of iron(II) by carbon-rich matrices in a hydrothermal plume

    Energy Technology Data Exchange (ETDEWEB)

    Toner, Brandy M.; Fakra, Sirine C.; Manganini, Steven J.; Santelli, Cara M.; Marcus, Matthew A.; Moffett, James W.; Rouxel, Olivier; German, Christopher R.; Edwards, Katrina J.

    2008-09-20

    Hydrothermal venting associated with mid-ocean ridge volcanism is globally widespread. This venting is responsible for a dissolved iron flux to the ocean that is approximately equal to that associated with continental riverine runoff. For hydrothermal fluxes, it has long been assumed that most of the iron entering the oceans is precipitated in inorganic forms. However, the possibility of globally significant fluxes of iron escaping these mass precipitation events and entering open-ocean cycles is now being debated, and two recent studies suggest that dissolved organic ligands might influence the fate of hydrothermally vented metals. Here we present spectromicroscopic measurements of iron and carbon in hydrothermal plume particles at the East Pacific Rise mid-ocean ridge. We show that organic carbon-rich matrices, containing evenly dispersed iron(II)-rich materials, are pervasive in hydrothermal plume particles. The absence of discrete iron(II) particles suggests that the carbon and iron associate through sorption or complexation. We suggest that these carbon matrices stabilize iron(II) released from hydrothermal vents in the region, preventing its oxidation and/or precipitation as insoluble minerals. Our findings have implications for deep-sea biogeochemical cycling of iron, a widely recognized limiting nutrient in the oceans.

  18. Will Invertebrates Require Increasingly Carbon-Rich Food in a Warming World?

    Science.gov (United States)

    Anderson, Thomas R; Hessen, Dag O; Boersma, Maarten; Urabe, Jotaro; Mayor, Daniel J

    2017-12-01

    Elevated temperature causes metabolism and respiration to increase in poikilothermic organisms. We hypothesized that invertebrate consumers will therefore require increasingly carbon-rich diets in a warming environment because the increased energetic demands are primarily met using compounds rich in carbon, that is, carbohydrates and lipids. Here, we test this hypothesis using a new stoichiometric model that has carbon (C) and nitrogen (N) as currencies. Model predictions did not support the hypothesis, indicating instead that the nutritional requirements of invertebrates, at least in terms of food quality expressed as C∶N ratio, may change little, if at all, at elevated temperature. Two factors contribute to this conclusion. First, invertebrates facing limitation by nutrient elements such as N have, by default, excess C in their food that can be used to meet the increased demand for energy in a warming environment, without recourse to extra dietary C. Second, increased feeding at elevated temperature compensates for the extra demands of metabolism to the extent that, when metabolism and intake scale equally with temperature (have the same Q 10 ), the relative requirement for dietary C and N remains unaltered. Our analysis demonstrates that future climate-driven increases in the C∶N ratios of autotroph biomass will likely exacerbate the stoichiometric mismatch between nutrient-limited invertebrate grazers and their food, with important consequences for C sequestration and nutrient cycling in ecosystems.

  19. Hydrogen substituted graphdiyne as carbon-rich flexible electrode for lithium and sodium ion batteries.

    Science.gov (United States)

    He, Jianjiang; Wang, Ning; Cui, Zili; Du, Huiping; Fu, Lin; Huang, Changshui; Yang, Ze; Shen, Xiangyan; Yi, Yuanping; Tu, Zeyi; Li, Yuliang

    2017-10-27

    Organic electrodes are potential alternatives to current inorganic electrode materials for lithium ion and sodium ion batteries powering portable and wearable electronics, in terms of their mechanical flexibility, function tunability and low cost. However, the low capacity, poor rate performance and rapid capacity degradation impede their practical application. Here, we concentrate on the molecular design for improved conductivity and capacity, and favorable bulk ion transport. Through an in situ cross-coupling reaction of triethynylbenzene on copper foil, the carbon-rich frame hydrogen substituted graphdiyne film is fabricated. The organic film can act as free-standing flexible electrode for both lithium ion and sodium ion batteries, and large reversible capacities of 1050 mAh g -1 for lithium ion batteries and 650 mAh g -1 for sodium ion batteries are achieved. The electrode also shows a superior rate and cycle performances owing to the extended π-conjugated system, and the hierarchical pore bulk with large surface area.

  20. Li dynamics in carbon-rich polymer-derived SiCN ceramics probed by NMR

    Science.gov (United States)

    Baek, Seung-Ho; Reinold, Lukas; Graczyk-Zajac, Magdalena; Riedel, Ralf; Hammerath, Franziska; Buechner, Bernd; Grafe, Hajo

    2014-03-01

    We report 7Li, 29Si, and 13C NMR studies of two different carbon-rich SiCN ceramics SiCN-1 and SiCN-3 derived from the preceramic polymers polyphenylvinylsilylcarbodiimide and polyphenylvinylsilazane, respectively. From the spectral analysis of the three nuclei at room temperature, we find that only the 13C spectrum is strongly influenced by Li insertion/extraction, suggesting that carbon phases are the major electrochemically active sites for Li storage. Temperature and Larmor frequency (ωL) dependences of the 7Li linewidth and spin-lattice relaxation rates T1-1 are described by an activated law with the activation energy EA of 0.31 eV and the correlation time τ0 in the high temperature limit of 1.3 ps. The 3 / 2 power law dependence of T1-1 on ωL which deviates from the standard Bloembergen, Purcell, and Pound (BPP) model implies that the Li motion on the μs timescale is governed by continuum diffusion mechanism rather than jump diffusion. On the other hand, the rotating frame relaxation rate T1ρ-1 results suggest that the slow motion of Li on the ms timescale may be affected by complex diffusion and/or non-diffusion processes.

  1. Mangroves among the most carbon-rich forests in the tropics

    Science.gov (United States)

    Donato, Daniel C.; Kauffman, J. Boone; Murdiyarso, Daniel; Kurnianto, Sofyan; Stidham, Melanie; Kanninen, Markku

    2011-05-01

    Mangrove forests occur along ocean coastlines throughout the tropics, and support numerous ecosystem services, including fisheries production and nutrient cycling. However, the areal extent of mangrove forests has declined by 30-50% over the past half century as a result of coastal development, aquaculture expansion and over-harvesting. Carbon emissions resulting from mangrove loss are uncertain, owing in part to a lack of broad-scale data on the amount of carbon stored in these ecosystems, particularly below ground. Here, we quantified whole-ecosystem carbon storage by measuring tree and dead wood biomass, soil carbon content, and soil depth in 25 mangrove forests across a broad area of the Indo-Pacific region--spanning 30° of latitude and 73° of longitude--where mangrove area and diversity are greatest. These data indicate that mangroves are among the most carbon-rich forests in the tropics, containing on average 1,023Mg carbon per hectare. Organic-rich soils ranged from 0.5m to more than 3m in depth and accounted for 49-98% of carbon storage in these systems. Combining our data with other published information, we estimate that mangrove deforestation generates emissions of 0.02-0.12Pg carbon per year--as much as around 10% of emissions from deforestation globally, despite accounting for just 0.7% of tropical forest area.

  2. AN EXTREMELY CARBON-RICH, EXTREMELY METAL-POOR STAR IN THE SEGUE 1 SYSTEM

    International Nuclear Information System (INIS)

    Norris, John E.; Yong, David; Gilmore, Gerard; Wyse, Rosemary F. G.; Frebel, Anna

    2010-01-01

    We report the analysis of high-resolution, high signal-to-noise ratio, spectra of an extremely metal-poor, extremely C-rich red giant, Seg 1-7, in Segue 1-described in the literature alternatively as an unusually extended globular cluster or an ultra-faint dwarf galaxy. The radial velocity of Seg 1-7 coincides precisely with the systemic velocity of Segue 1, and its chemical abundance signature of [Fe/H] = -3.52, [C/Fe] = +2.3, [N/Fe] = +0.8, [Na/Fe] = +0.53, [Mg/Fe] = +0.94, [Al/Fe] = +0.23, and [Ba/Fe] < -1.0 is similar to that of the rare and enigmatic class of Galactic halo objects designated CEMP-no (carbon-rich, extremely metal-poor with no enhancement (over solar ratios) of heavy neutron-capture elements). This is the first star in a Milky Way 'satellite' that unambiguously lies on the metal-poor, C-rich branch of the Aoki et al. bimodal distribution of field halo stars in the ([C/Fe], [Fe/H])-plane. Available data permit us only to identify Seg 1-7 as a member of an ultra-faint dwarf galaxy or as debris from the Sgr dwarf spheroidal galaxy. In either case, this demonstrates that at extremely low abundance, [Fe/H ] <-3.0, star formation and associated chemical evolution proceeded similarly in the progenitors of both the field halo and satellite systems. By extension, this is consistent with other recent suggestions that the most metal-poor dwarf spheroidal and ultra-faint dwarf satellites were the building blocks of the Galaxy's outer halo.

  3. Deforestation projections for carbon-rich peat swamp forests of Central Kalimantan, Indonesia.

    Science.gov (United States)

    Fuller, Douglas O; Hardiono, Martin; Meijaard, Erik

    2011-09-01

    We evaluated three spatially explicit land use and cover change (LUCC) models to project deforestation from 2005-2020 in the carbon-rich peat swamp forests (PSF) of Central Kalimantan, Indonesia. Such models are increasingly used to evaluate the impact of deforestation on carbon fluxes between the biosphere and the atmosphere. We considered both business-as-usual (BAU) and a forest protection scenario to evaluate each model's accuracy, sensitivity, and total projected deforestation and landscape-level fragmentation patterns. The three models, Dinamica EGO (DE), GEOMOD and the Land Change Modeler (LCM), projected similar total deforestation amounts by 2020 with a mean of 1.01 million ha (Mha) and standard deviation of 0.17 Mha. The inclusion of a 0.54 Mha strict protected area in the LCM simulations reduced projected loss to 0.77 Mha over 15 years. Calibrated parameterizations of the models using nearly identical input drivers produced very different landscape properties, as measured by the number of forest patches, mean patch area, contagion, and Euclidean nearest neighbor determined using Fragstats software. The average BAU outputs of the models suggests that Central Kalimantan may lose slightly less than half (45.1%) of its 2005 PSF by 2020 if measures are not taken to reduce deforestation there. The relatively small reduction of 0.24 Mha in deforestation found in the 0.54 Mha protection scenario suggests that these models can identify potential leakage effects in which deforestation is forced to occur elsewhere in response to a policy intervention.

  4. Supramolecular chemistry and crystal engineering

    Indian Academy of Sciences (India)

    supramolecular architectures, network structures, multi-component host–guest systems, cocrys- tals, and ... structures is illustrated by two important prototypes – the large unit cell of elusive saccharin hydrate ..... N––– H ··· π interaction is not seen in this view. (d) Infinite .... to atmospheric water vapor without color loss or.

  5. Reversible networks in supramolecular polymers

    NARCIS (Netherlands)

    Havermans - van Beek, D.J.M.

    2007-01-01

    Non–covalent interactions between low molecular weight polymers form the basis of supramolecular polymers. The material properties of such polymers are determined by the strength and lifetime of the non–covalent reversible interactions. Due to the reversibility of the interactions between the low

  6. Stoichiometric control of multiple different tectons in coordination-driven self-assembly: preparation of fused metallacyclic polygons.

    Science.gov (United States)

    Lee, Junseong; Ghosh, Koushik; Stang, Peter J

    2009-09-02

    We present a general strategy for the synthesis of stable, multicomponent fused polygon complexes in which coordination-driven self-assembly allows for single supramolecular species to be formed from multicomponent self-assembly and the shape of the obtained polygons can be controlled simply by changing the ratio of individual components. The compounds have been characterized by multinuclear NMR spectroscopy and electrospray ionization mass spectrometry.

  7. Efficacy and tolerability of hydrogen carbonate-rich water for heartburn

    Science.gov (United States)

    Beer, André-Michael; Uebelhack, Ralf; Pohl, Ute

    2016-01-01

    requested and were analyzed as ITT population. The occurrence of heartburn was statistically significantly reduced at wk 6 in both the ITT and the PP populations. At wk 6, the mean number of heartburn episodes/week decreased by 5.1 episodes (P heartburn symptoms by 19 min (ITT) (P = 0.002). The frequency of heartburn symptoms was reduced in 89.6% of the patients (P heartburn, regurgitation, gastro-esophageal reflux disease symptoms, dyspepsia) showed a significant improvement at 6 wk. Likewise, disease-specific quality of life improved significantly (QOLRAD, GIQLI). Overall, 89.4% of patients rated the efficacy of the test water as “good” or “very good”, as did the investigators for 91.5% of the patients. There were no serious AEs. After 6 wk, systolic and diastolic blood pressure values decreased slightly but significantly [-3.5 and -3.0 mmHg, respectively (P = 0.008 and P = 0,002)]. Ninety-six percent of patients and investigators for the same percentage of patients rated the tolerability of the water as “good” or “very good”. CONCLUSION: The data demonstrate effectiveness of a hydrogen carbonate-rich mineral water in alleviating heartburn frequency and severity, thereby improving quality of life. The water has excellent tolerability. PMID:26909240

  8. Topological dynamics in supramolecular rotors.

    Science.gov (United States)

    Palma, Carlos-Andres; Björk, Jonas; Rao, Francesco; Kühne, Dirk; Klappenberger, Florian; Barth, Johannes V

    2014-08-13

    Artificial molecular switches, rotors, and machines are set to establish design rules and applications beyond their biological counterparts. Herein we exemplify the role of noncovalent interactions and transient rearrangements in the complex behavior of supramolecular rotors caged in a 2D metal-organic coordination network. Combined scanning tunneling microscopy experiments and molecular dynamics modeling of a supramolecular rotor with respective rotation rates matching with 0.2 kcal mol(-1) (9 meV) precision, identify key steps in collective rotation events and reconfigurations. We notably reveal that stereoisomerization of the chiral trimeric units entails topological isomerization whereas rotation occurs in a topology conserving, two-step asynchronous process. In supramolecular constructs, distinct displacements of subunits occur inducing a markedly lower rotation barrier as compared to synchronous mechanisms of rigid rotors. Moreover, the chemical environment can be instructed to control the system dynamics. Our observations allow for a definition of mechanical cooperativity based on a significant reduction of free energy barriers in supramolecules compared to rigid molecules.

  9. Non-equilibrium supramolecular polymerization.

    Science.gov (United States)

    Sorrenti, Alessandro; Leira-Iglesias, Jorge; Markvoort, Albert J; de Greef, Tom F A; Hermans, Thomas M

    2017-09-18

    Supramolecular polymerization has been traditionally focused on the thermodynamic equilibrium state, where one-dimensional assemblies reside at the global minimum of the Gibbs free energy. The pathway and rate to reach the equilibrium state are irrelevant, and the resulting assemblies remain unchanged over time. In the past decade, the focus has shifted to kinetically trapped (non-dissipative non-equilibrium) structures that heavily depend on the method of preparation (i.e., pathway complexity), and where the assembly rates are of key importance. Kinetic models have greatly improved our understanding of competing pathways, and shown how to steer supramolecular polymerization in the desired direction (i.e., pathway selection). The most recent innovation in the field relies on energy or mass input that is dissipated to keep the system away from the thermodynamic equilibrium (or from other non-dissipative states). This tutorial review aims to provide the reader with a set of tools to identify different types of self-assembled states that have been explored so far. In particular, we aim to clarify the often unclear use of the term "non-equilibrium self-assembly" by subdividing systems into dissipative, and non-dissipative non-equilibrium states. Examples are given for each of the states, with a focus on non-dissipative non-equilibrium states found in one-dimensional supramolecular polymerization.

  10. Transfer of 241Am and 237Pu from euphausiid moults to a carbonate-rich marine sediment

    International Nuclear Information System (INIS)

    Hargrave, B.T.

    1986-01-01

    Concentrations of 241 Am and 237 Pu adsorbed onto moulted exoskeletons from the euphausiid Meganyctiphanes norvegica decreased exponentially with 50% retention times of 3-7 d when moults were incubated in filtered seawater with small amounts of carbonate-rich sediment. Over 95% of sediment weight was present as -2 ) was greatest in the medium-fine sand fraction which had the highest carbonate content. These particles constituted -2 surface: atoms μm -3 in solution) was 10 3 -10 4 times higher than similar quotients for 241 Am and 237 Pu sorbed to surfaces of organic particles are transferred to sediments. (author)

  11. Multivalency in supramolecular chemistry and nanofabrication

    NARCIS (Netherlands)

    Mulder, A.; Huskens, Jurriaan; Reinhoudt, David

    2004-01-01

    Multivalency is a powerful and versatile self-assembly pathway that confers unique thermodynamic and kinetic behavior onto supramolecular complexes. The diversity of the examples of supramolecular multivalent systems discussed in this perspective shows that the concept of multivalency is a general

  12. Metallo-supramolecular block copolymer micelles

    NARCIS (Netherlands)

    Gohy, J.M.W.

    2009-01-01

    Supramolecular copolymers have become of increasing interest in recent years in the search for new materials with tunable properties. In particular, metallo-supramolecular block copolymers in which metal-ligand complexes are introduced in block copolymer architectures, have known important progress,

  13. Construction of diverse supramolecular assemblies of dimetal ...

    Indian Academy of Sciences (India)

    presence or absence of the lattice water molecules are the keys to forming the diverse supramolecular assem- blies. In 1 and 3, ... Supramolecular; hydrogen bonding; flexible ligand; dicarboxylates. 1. ... The reaction mixture was stirred for another 3 to 4 hours at room ..... Funding for this work was provided by IISER, Mohali.

  14. Synthesis, Molecular Structure and Cytotoxicity of Molecular Materials Based on Water Soluble Half-Sandwich Rh(III) and Ir(III) Tetranuclear Metalla-Cycles

    Science.gov (United States)

    Gupta, Gajendra; Murray, Benjamin S.; Dyson, Paul J.; Therrien, Bruno

    2013-01-01

    The neutral dinuclear complexes [(η5-C5Me5)2Rh2(μ-dhnq)Cl2] (1) and [(η5-C5Me5)2Ir2(μ-dhnq)Cl2] (2) (dhnqH2 = 5,8-dihydroxy-1,4-naphthoquinone) were obtained from the reaction of [(η5-C5Me5)M(μ-Cl)Cl]2 (M = Rh, Ir) with dhnqH2 in the presence of CH3COONa. Treatment of 1 or 2 in methanol with linear ditopic ligands L (L = pyrazine, 4,4′-bipyridine or 1,2-bis(4-pyridyl)ethylene), in the presence of AgCF3SO3, affords the corresponding tetranuclear metalla-rectangles [(η5-C5Me5)4M4(μ-dhnq)2(μ-L)2]4+ (L = pyrazine, M = Rh, 3; M = Ir, 4; L = 4,4′-bipyridine, M = Rh, 5; M = Ir, 6; L = 1,2-bis(4-pyridyl)ethylene, M = Rh, 7; M = Ir, 8). All complexes were isolated as their triflate salts and were fully characterized by infrared, 1H and 13C NMR spectroscopy, and some representative complexes by single-crystal X-ray structure analysis. The X-ray structures of 3, 5 and 6 confirm the formation of the tetranuclear metalla-cycles, and suggest that complexes 5 and 6 possess a cavity of sufficient size to encapsulate small guest molecules. In addition, the antiproliferative activity of the metalla-cycles 3–8 was evaluated against the human ovarian A2780 (cisplatin sensitive) and A2780cisR (cisplatin resistant) cancer cell lines and on non-tumorigenic human embryonic kidney HEK293 cells. All cationic tetranuclear metalla-rectangles were found to be highly cytotoxic, with IC50 values in the low micromolar range. PMID:28788394

  15. Synthesis, Molecular Structure and Cytotoxicity of Molecular Materials Based on Water Soluble Half-Sandwich Rh(III and Ir(III Tetranuclear Metalla-Cycles

    Directory of Open Access Journals (Sweden)

    Gajendra Gupta

    2013-11-01

    Full Text Available The neutral dinuclear complexes [(η5-C5Me52Rh2(μ-dhnqCl2] (1 and [(η5-C5Me52Ir2(μ-dhnqCl2] (2 (dhnqH2 = 5,8-dihydroxy-1,4-naphthoquinone were obtained from the reaction of [(η5-C5Me5M(μ-ClCl]2 (M = Rh, Ir with dhnqH2 in the presence of CH3COONa. Treatment of 1 or 2 in methanol with linear ditopic ligands L (L = pyrazine, 4,4′-bipyridine or 1,2-bis(4-pyridylethylene, in the presence of AgCF3SO3, affords the corresponding tetranuclear metalla-rectangles [(η5-C5Me54M4(μ-dhnq2(μ-L2]4+ (L = pyrazine, M = Rh, 3; M = Ir, 4; L = 4,4′-bipyridine, M = Rh, 5; M = Ir, 6; L = 1,2-bis(4-pyridylethylene, M = Rh, 7; M = Ir, 8. All complexes were isolated as their triflate salts and were fully characterized by infrared, 1H and 13C NMR spectroscopy, and some representative complexes by single-crystal X-ray structure analysis. The X-ray structures of 3, 5 and 6 confirm the formation of the tetranuclear metalla-cycles, and suggest that complexes 5 and 6 possess a cavity of sufficient size to encapsulate small guest molecules. In addition, the antiproliferative activity of the metalla-cycles 3–8 was evaluated against the human ovarian A2780 (cisplatin sensitive and A2780cisR (cisplatin resistant cancer cell lines and on non-tumorigenic human embryonic kidney HEK293 cells. All cationic tetranuclear metalla-rectangles were found to be highly cytotoxic, with IC50 values in the low micromolar range.

  16. Supramolecular Structure and Function 9

    CERN Document Server

    Pifat-Mrzljak, Greta

    2007-01-01

    The book is based on International Summer Schools on Biophysics held in Croatia which, contrary to other workshops centered mainly on one topic or technique, has very broad scope providing advanced training in areas related to biophysics. This volume is presenting papers in the field of biophysics for studying biological phenomena by using physical methods (NMR, EPR, FTIR, Mass Spectrometry, etc.) and/or concepts (predictions of protein-protein interactions, virtual ligand screening etc.). The interrelationship of supramolecular structures and there functions is enlightened by applications of principals of these physical methods in the biophysical and molecular biology context.

  17. Successive Recovery of Copper and Uranium From Carbonate-Rich Latosol, Um Bogma Formation, Abuthor Locality, South Western Sinai, Egypt

    International Nuclear Information System (INIS)

    El-Sheikh, E.M.; Amin, M.M.; Aita, S.K.; Rezk, A.A.

    2013-01-01

    A technological sample of a copper/ uranium mineralization in carbonate rich latosol rock sequence of Urn Bogma Formation Abu Thor locality at southwestern Sinai, Egypt, has been properly processed. The working sample assaying 12.5 % CuO and 875 ppm U was subjected to adipic acid leaching for copper followed by bioleaching of uranium in a manner to avoid excessive acid consumption in the classical leaching procedure. It is thus possible to achieve leaching efficiencies of 95% for Cu in the first stage and 82% for U in the second stage. From the two separately obtained leach liquors of Cu and uranium, pure products have conveniently been prepared. Accordingly, Cu adipate product was first prepared by crystallization,followed by acid dissolution and alkali precipitation of copper hydroxide. In case of uranium, the impure precipitate of the bioleach liquor is purified via Amberlite IRA-400 anion exchanger resin

  18. Hg and Pt-metals in meteorite carbon-rich residues - Suggestions for possible host phase for Hg

    Science.gov (United States)

    Jovanovic, S.; Reed, G. W., Jr.

    1980-01-01

    Carbon-rich and oxide residual phases have been isolated from Allende and Murchison by acid demineralization for the determination of their Hg, Pt-metal, Cr, Sc, Co, and Fe contents. Experimental procedures used eliminated the possibility of exogenous and endogenous contaminant trace elements from coprecipitating with the residues. Large enrichments of Hg and Pt-metals were found in Allende but not in Murchison residues. Hg-release profiles from stepwise heating experiments suggest a sulfide as the host for Hg. Diffusion calculations for Hg based on these experiments indicate an activation energy of 7-8 kcal/mol, the same as that for Hg in troilite from an iron meteorite. This is further support for a sulfide host phase for Hg. Equilibration of Hg with this phase at approximately 900 K is indicated. Reasons for the presence of Pt-metals in noncosmic relative abundances are explored.

  19. Shale-brine-CO2 interactions and the long-term stability of carbonate-rich shale caprock

    Science.gov (United States)

    Ilgen, A.; Aman, M.; Espinoza, D. N.; Rodriguez, M. A.; Griego, J.; Dewers, T. A.; Feldman, J.; Stewart, T.; Choens, R. C., II

    2017-12-01

    Geological carbon storage (GCS) requires an impermeable caprock (e.g., shale) that prevents the upward migration and escape of carbon dioxide (CO2) from the subsurface. Geochemical alteration can occur at the caprock-reservoir rock interface, which could lead to the altering of the rock's mechanical properties, compromising the seal. We performed laboratory experiments on Mancos shale to quantify the coupled chemical-mechanical response of carbonate-rich shale in CO2-brine mixtures at conditions typical to GCS. We constructed geochemical models, calibrated them using laboratory results, and extended to time scales required for GCS. We observed the dissolution of calcite and kaolinite and the precipitation of gypsum and amorphous aluminum (hydr)oxide following the introduction of CO2. To address whether this mineral alteration causes changes in micro-mechanical properties, we examined altered Mancos shale using micro-mechanical (scratch) testing, measuring the scratch toughness of mm-scale shale lithofacies. The quartz-rich regions of the Mancos shale did not show significant changes in scratch toughness following 1-week alteration in a CO2-brine mixture. However, the scratch toughness of the calcite-rich, originally softer regions decreased by about 50%. These observations illustrate a coupled and localized chemical-mechanical response of carbonate-rich shale to the injection of CO2. This suggests a localized weakening of the caprock may occur, potentially leading to the development of preferential flow paths. The identification of vulnerable lithofacies within caprock and a characterization of mineralogical heterogeneity is imperative at prospective GCS sites. Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy's National Nuclear Security Administration under contract DE

  20. Main-chain supramolecular block copolymers.

    Science.gov (United States)

    Yang, Si Kyung; Ambade, Ashootosh V; Weck, Marcus

    2011-01-01

    Block copolymers are key building blocks for a variety of applications ranging from electronic devices to drug delivery. The material properties of block copolymers can be tuned and potentially improved by introducing noncovalent interactions in place of covalent linkages between polymeric blocks resulting in the formation of supramolecular block copolymers. Such materials combine the microphase separation behavior inherent to block copolymers with the responsiveness of supramolecular materials thereby affording dynamic and reversible materials. This tutorial review covers recent advances in main-chain supramolecular block copolymers and describes the design principles, synthetic approaches, advantages, and potential applications.

  1. Enhanced intermolecular forces in supramolecular polymer nanocomposites

    Directory of Open Access Journals (Sweden)

    F. Lin

    2017-09-01

    Full Text Available Ureido-pyrimidone (Upy can dimerize in a self-complementary array of quadruple hydrogen bonds. In this paper, supramolecular polymer composites were prepared by blending Upy functionalized nanosilica with Upy end-capped polycarbonatediol. Surface characteristics of Upy functionalized nanosilica and influences of supramolecular forces on interfacial binding were researched. Fourier transform infrared spectroscopy (FTIR, Nuclear magnetic resonance (NMR and Gel permeation chromatography (GPC were used to characterize the synthesized molecules. Grafting ratio of Upy segments on the surface of nanosilica was analysed by Thermogravimetic analysis (TGA. Hydrophobicity and morphology of Upy modified nanosilica were analysed by Contact angle tester and Scanning electron microscope (SEM. Furthermore, dynamic thermo mechanical properties, mechanical properties and distribution of nanosilica in supramolecular polymer composites were also researched. Compared with the matrix resin, tensile stress and young's modulus of supramolecular polymer composites containing 5 wt% modified nanosilica were increased by 292 and 198% respectively.

  2. Solvent induced supramolecular anisotropy in molecular gels

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, Michael A., E-mail: mroger09@uoguelph.ca [Department of Food Science, University of Guelph, Guelph, Ontario, N3C3X9 (Canada); Corradini, Maria G. [Department of Food Science, University of Massachusetts Amherst, Amherst, MA, 01003 (United States); Emge, Thomas [Department of Chemistry and Biochemistry, Rutgers University, New Brunswick, NJ, 08901 (United States)

    2017-06-15

    Herein is the first report of solvent induced anisotropy in 12-hydroxystearic acid self-assembled fibrillar networks. Increasing the chain length of polar solvent, such as nitriles and ketones, tailored the anisotropy of the fibrillar aggregates. 12HSA molecular gels, comprised of alkanes, exhibited an isotropic fibrillar network irrespective of the alkane chain length. In polar solvents, anisotropy, observed using 2D powder x-ray diffraction profiles, is correlated to a fibrillar supramolecular morphologies in long chain nitriles and ketones while sphereulitic crystals are correlated to x-ray diffraction patterns with an isotropic scatter intensity in short chain ketones and nitriles. These changes directly modify the final physical properties of the gels. - Highlights: • 12-HSA self-assembles into crystalline supramolecular morphologies depending on the solvent. • Alkanes, short chain nitriles and ketones led to 12-HSA displaying supramolecular isotropy. • In long chain nitriles and ketones, 12-HSA displays supramolecular anisotropy.

  3. Solvent induced supramolecular anisotropy in molecular gels

    International Nuclear Information System (INIS)

    Rogers, Michael A.; Corradini, Maria G.; Emge, Thomas

    2017-01-01

    Herein is the first report of solvent induced anisotropy in 12-hydroxystearic acid self-assembled fibrillar networks. Increasing the chain length of polar solvent, such as nitriles and ketones, tailored the anisotropy of the fibrillar aggregates. 12HSA molecular gels, comprised of alkanes, exhibited an isotropic fibrillar network irrespective of the alkane chain length. In polar solvents, anisotropy, observed using 2D powder x-ray diffraction profiles, is correlated to a fibrillar supramolecular morphologies in long chain nitriles and ketones while sphereulitic crystals are correlated to x-ray diffraction patterns with an isotropic scatter intensity in short chain ketones and nitriles. These changes directly modify the final physical properties of the gels. - Highlights: • 12-HSA self-assembles into crystalline supramolecular morphologies depending on the solvent. • Alkanes, short chain nitriles and ketones led to 12-HSA displaying supramolecular isotropy. • In long chain nitriles and ketones, 12-HSA displays supramolecular anisotropy.

  4. Supramolecular protein immobilization on lipid bilayers

    NARCIS (Netherlands)

    Bosmans, R.P.G.; Hendriksen, W.E.; Verheijden, Mark Lloyd; Eelkema, R.; Jonkheijm, Pascal; van Esch, J.H.; Brunsveld, Luc

    2015-01-01

    Protein immobilization on surfaces, and on lipid bilayers specifically, has great potential in biomolecular and biotechnological research. Of current special interest is the immobilization of proteins using supramolecular noncovalent interactions. This allows for a reversible immobilization and

  5. Supramolecular chemistry - interdisciplinary branch of science

    International Nuclear Information System (INIS)

    Radecka-Paryzek, W.

    1997-01-01

    The scientific problems connected with supramolecular chemistry have been reviewed. The basic concepts have been defined as well as rules governed of macromolecules formation. The special emphasize has been put on present and possible in future application of such systems

  6. Herschel/HIFI Observations of IRC+10216: Water Vapor in the Inner Envelope of a Carbon-rich Asymptotic Giant Branch Star

    NARCIS (Netherlands)

    Neufeld, D. A.; González-Alfonso, E.; Melnick, G.; Szczerba, R.; Schmidt, M.; Decin, L.; de Koter, A.; Schöier, F. L.; Cernicharo, J.

    2011-01-01

    We report the results of observations of 10 rotational transitions of water vapor toward the carbon-rich asymptotic giant branch (AGB) star IRC+10216 (CW Leonis), carried out with Herschel's HIFI instrument. Each transition was securely detected by means of observations using the dual beam switch

  7. Lithium dynamics in carbon-rich polymer-derived SiCN ceramics probed by nuclear magnetic resonance

    Science.gov (United States)

    Baek, Seung-Ho; Reinold, Lukas Mirko; Graczyk-Zajac, Magdalena; Riedel, Ralf; Hammerath, Franziska; Büchner, Bernd; Grafe, Hans-Joachim

    2014-05-01

    We report 7Li, 29Si, and 13C NMR studies of two different carbon-rich SiCN ceramics SiCN-1 and SiCN-3 derived from the preceramic polymers polyphenylvinylsilylcarbodiimide and polyphenylvinylsilazane, respectively. From the spectral analysis of the three nuclei, we find that only the 13C spectrum is strongly influenced by Li insertion/extraction, suggesting that carbon phases are the major electrochemically active sites for Li storage. Temperature (T) and Larmor frequency (ωL) dependences of the 7Li linewidth and spin-lattice relaxation rates T1-1 are described by an activated law with the activation energy EA of 0.31 eV and the correlation time τ0 in the high temperature limit of 1.3 ps. The 3 / 2 power law dependence of T1-1 on ωL which deviates from the standard Bloembergen, Purcell, and Pound (BPP) model implies that the Li motion on the μs timescale is governed by continuum diffusion mechanism rather than jump diffusion. On the other hand, the rotating frame relaxation rate T1ρ-1 results suggest that the slow motion of Li on the ms timescale may be affected by complex diffusion and/or non-diffusion processes.

  8. Evidence for Reduced, Carbon-rich Regions in the Solar Nebula from an Unusual Cometary Dust Particle

    Energy Technology Data Exchange (ETDEWEB)

    De Gregorio, Bradley T.; Stroud, Rhonda M. [Materials Science and Technology Division, Naval Research Laboratory, Code 6366, 4555 Overlook Avenue SW, Washington, DC 20375 (United States); Nittler, Larry R. [Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Road NW, Washington, DC 20015 (United States); Kilcoyne, A. L. David, E-mail: bradley.degregorio@nrl.navy.mil [Advanced Light Source, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Mailstop 7R0222, Berkeley, CA 94720 (United States)

    2017-10-20

    Geochemical indicators in meteorites imply that most formed under relatively oxidizing conditions. However, some planetary materials, such as the enstatite chondrites, aubrite achondrites, and Mercury, were produced in reduced nebular environments. Because of large-scale radial nebular mixing, comets and other Kuiper Belt objects likely contain some primitive material related to these reduced planetary bodies. Here, we describe an unusual assemblage in a dust particle from comet 81P/Wild 2 captured in silica aerogel by the NASA Stardust spacecraft. The bulk of this ∼20 μ m particle is comprised of an aggregate of nanoparticulate Cr-rich magnetite, containing opaque sub-domains composed of poorly graphitized carbon (PGC). The PGC forms conformal shells around tiny 5–15 nm core grains of Fe carbide. The C, N, and O isotopic compositions of these components are identical within errors to terrestrial standards, indicating a formation inside the solar system. Magnetite compositions are consistent with oxidation of reduced metal, similar to that seen in enstatite chondrites. Similarly, the core–shell structure of the carbide + PGC inclusions suggests a formation via FTT reactions on the surface of metal or carbide grains in warm, reduced regions of the solar nebula. Together, the nanoscale assemblage in the cometary particle is most consistent with the alteration of primary solids condensed from a C-rich, reduced nebular gas. The nanoparticulate components in the cometary particle provide the first direct evidence from comets of reduced, carbon-rich regions that were present in the solar nebula.

  9. Functional supramolecular polymers for biomedical applications.

    Science.gov (United States)

    Dong, Ruijiao; Zhou, Yongfeng; Huang, Xiaohua; Zhu, Xinyuan; Lu, Yunfeng; Shen, Jian

    2015-01-21

    As a novel class of dynamic and non-covalent polymers, supramolecular polymers not only display specific structural and physicochemical properties, but also have the ability to undergo reversible changes of structure, shape, and function in response to diverse external stimuli, making them promising candidates for widespread applications ranging from academic research to industrial fields. By an elegant combination of dynamic/reversible structures with exceptional functions, functional supramolecular polymers are attracting increasing attention in various fields. In particular, functional supramolecular polymers offer several unique advantages, including inherent degradable polymer backbones, smart responsiveness to various biological stimuli, and the ease for the incorporation of multiple biofunctionalities (e.g., targeting and bioactivity), thereby showing great potential for a wide range of applications in the biomedical field. In this Review, the trends and representative achievements in the design and synthesis of supramolecular polymers with specific functions are summarized, as well as their wide-ranging biomedical applications such as drug delivery, gene transfection, protein delivery, bio-imaging and diagnosis, tissue engineering, and biomimetic chemistry. These achievements further inspire persistent efforts in an emerging interdisciplin-ary research area of supramolecular chemistry, polymer science, material science, biomedical engineering, and nanotechnology. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Arsenic mobility in groundwater/surface water systems in carbonate-rich Pleistocene glacial drift aquifers (Michigan)

    International Nuclear Information System (INIS)

    Szramek, Kathryn; Walter, Lynn M.; McCall, Patti

    2004-01-01

    Within the Lower Peninsula of Michigan, groundwaters from the Marshall Formation (Mississippian) contain As derived from As-rich pyrites, often exceeding the World Heath Organization drinking water limit of 10 μg/L. Many Michigan watersheds, established on top of Pleistocene glacial drift derived from erosion of the underlying Marshall Formation, also have waters with elevated As. The Huron River watershed in southeastern Lower Michigan is a well characterized hydrogeochemical system of glacial drift deposits, proximate to the Marshall Fm. subcrop, which hosts carbonate-rich groundwaters, streams, and wetlands (fens), and well-developed soil profiles. Aqueous and solid phase geochemistry was determined for soils, soil waters, surface waters (streams and fens) and groundwaters from glacial drift aquifers to better understand the hydrogeologic and chemical controls on As mobility. Soil profiles established on the glacial drift exhibit enrichment in both Fe and As in the oxyhydroxide-rich zone of accumulation. The amounts of Fe and As present as oxyhydroxides are comparable to those reported from bulk Marshall Fm. core samples by previous workers. However, the As host in core samples is largely unaltered pyrite and arsenopyrite. This suggests that the transformation of Fe sulfides to Fe oxyhydroxides largely retains As and Fe at the oxidative weathering site. Groundwaters have the highest As values of all the waters sampled, and many were at or above the World Health limit. Most groundwaters are anaerobic, within the zones of Fe 3+ and As(V) reduction. Although reduction of Fe(III) oxyhydroxides is the probable source of As, there is no correlation between As and Fe concentrations. The As/Fe mole ratios in drift groundwaters are about an order of magnitude greater than those in soil profiles, suggesting that As is more mobile than Fe. This is consistent with the dominance of As(III) in these groundwaters and with the partitioning of Fe 2+ into carbonate cements. Soil

  11. Comet C2012 S1 (ISON)s Carbon-rich and Micron-size-dominated Coma Dust

    Science.gov (United States)

    Wooden, D.; De Buizer, J.; Kelley, M.; Sitko, M.; Woodward, C.; Harker, D.; Reach, W.; Russell, R.; Kim, D.; Yanamadra-Fisher, P.; hide

    2014-01-01

    Comet C/2012 S1 (ISON) was unique in that it was a dynamically new comet derived from the Nearly Isotropic Oort cloud reservoir of comets with a sun-grazing orbit. We present thermal models for comet ISON (rh approx.1.15 AU, 2013-Oct-25 11:30 UT) that reveal comet ISON's dust was carbon-rich and dominated by a narrow size distribution dominated by approx. micron-sized grains. We constrained the models by our SOFIA FORCAST photometry at 11.1, 19.7 and 31.5 microns and by a silicate feature strength of approx.1.1 and an 8-13microns continuum greybody color temperature of approx. 275-280 K (using Tbb ? r-0.5 h and Tbb approx. 260-265 K from Subaru COMICS, 2013-Oct-19 UT)[1,2]. N-band spectra of comet ISON with the BASS instrument on the NASA IRTF (2013-Nov-11-12 UT) show a silicate feature strength of approx. 1.1 and an 11.2microns forsterite peak.[3] Our thermal models yield constraints the dust composition as well as grain size distribution parameters: slope, peak grain size, porosity. Specifically, ISON's dust has a low silicate-to- amorphous carbon ratio (approx. 1:9), and the coma size distribution has a steep slope (N4.5) such that the coma is dominated by micron-sized, moderately porous, carbon-rich dust grains. The N-band continuum color temperature implies submicronto micron-size grains and the steep fall off of the SOFIA far-IR photometry requires the size distribution to have fewer relative numbers of larger and cooler grains compared to smaller and hotter grains. A proxy for the dust production rate is f? approx.1500 cm, akin to Af?. ISON has a moderate-to-low dust-to-gas ratio. Comet ISON's dust grain size distribution does not appear similar to the few well-studied long-period Nearly Isotropic Comets (NICs), namely C/1995 O1 (Hale-Bopp) and C/2001 Q4 (NEAT) that had smaller and/or more highly porous grains and larger sizes, or C/2007 N4 (Lulin) and C/2006 P1 (McNaught) that had large and/or compact grains. Radial transport to comet-forming disk distances

  12. Spectral Evidence for an Inner Carbon-rich Circumstellar Belt in the Young HD 36546 A-star System

    Energy Technology Data Exchange (ETDEWEB)

    Lisse, C. M. [JHU-APL, 11100 Johns Hopkins Road, Laurel, MD 20723 (United States); Sitko, M. L. [Department of Physics, University of Cincinnati, Cincinnati, OH 45221-0011 and Space Science Institute, Boulder, CO 80301 (United States); Russell, R. W. [The Aerospace Corporation, Los Angeles, CA 90009 (United States); Marengo, M. [Department of Physics and Astronomy, 12 Physics Hall, Iowa State University, Ames, IA 50010 (United States); Currie, T. [Subaru Telescope, National Astronomical Observatory of Japan, National Institutes of Natural Sciences, Hilo, HI 96720 (United States); Melis, C. [Center for Astrophysics and Space Sciences, University of California, San Diego, CA 92093-0424 (United States); Mittal, T. [Department of Earth and Planetary Sciences, McCone Hall, University of California at Berkeley, Berkeley, CA 94720 (United States); Song, I., E-mail: carey.lisse@jhuapl.edu, E-mail: ron.vervack@jhuapl.edu, E-mail: sitkoml@ucmail.uc.edu, E-mail: ray.russell@aero.org, E-mail: mmarengo@iastate.edu, E-mail: currie@naoj.org, E-mail: cmelis@ucsd.edu, E-mail: tmittal2@berkeley.edu, E-mail: song@physast.uga.edu [Department of Physics and Astronomy, University of Georgia, Athens, GA 30602-2451 (United States)

    2017-05-10

    Using the NASA/IRTF SpeX and BASS spectrometers we have obtained 0.7–13 μ m observations of the newly imaged 3–10 Myr old HD 36546 disk system. The SpeX spectrum is most consistent with the photospheric emission expected from an L {sub *} ∼ 20 L {sub ⊙}, solar abundance A1.5V star with little to no extinction, and excess emission from circumstellar dust detectable beyond 4.5 μ m. Non-detections of CO emission lines and accretion signatures point to the gas-poor circumstellar environment of a very old transition disk. Combining the SpeX + BASS spectra with archival WISE / AKARI / IRAS / Herschel photometry, we find an outer cold dust belt at ∼135 K and 20–40 au from the primary, likely coincident with the disk imaged by Subaru, and a new second inner belt with a temperature ∼570 K and an unusual, broad SED maximum in the 6–9 μ m region, tracing dust at 1.1–2.2 au. An SED maximum at 6–9 μ m has been reported in just two other A-star systems, HD 131488 and HD 121191, both of ∼10 Myr age. From Spitzer , we have also identified the ∼12 Myr old A7V HD 148657 system as having similar 5–35 μ m excess spectral features. The Spitzer data allows us to rule out water emission and rule in carbonaceous materials—organics, carbonates, SiC—as the source of the 6–9 μ m excess. Assuming a common origin for the four young A-star systems’ disks, we suggest they are experiencing an early era of carbon-rich planetesimal processing.

  13. Carbon-rich dust past the asymptotic giant branch: Aliphatics, aromatics, and fullerenes in the Magellanic Clouds

    Energy Technology Data Exchange (ETDEWEB)

    Sloan, G. C.; Lagadec, E. [Center for Radiophysics and Space Research, Cornell University, Ithaca, NY 14853-6801 (United States); Zijlstra, A. A. [Jodrell Bank Centre for Astrophysics, University of Manchester, Manchester M13 9PL (United Kingdom); Kraemer, K. E. [Institute for Scientific Research, Boston College, 140 Commonwealth Avenue, Chestnut Hill, MA 02467 (United States); Weis, A. P. [Department of Astronomy and Astrophysics, Columbia University, 550 West 120th Street, New York, NY 10027 (United States); Matsuura, M. [Astrophysics Group, Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom); Volk, K. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Peeters, E.; Cami, J. [Department of Physics and Astronomy, University of Western Ontario, London, ON N6A 3K7 (Canada); Duley, W. W. [Department of Physics and Astronomy, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1 (Canada); Bernard-Salas, J. [Department of Physical Sciences, The Open University, Walton Hall, Milton Keynes, MK7 6AA (United Kingdom); Kemper, F. [Academia Sinica, Institute of Astronomy and Astrophysics, 11F Astronomy-Mathematics Building, NTU/AS, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan, R.O.C (China); Sahai, R., E-mail: sloan@isc.astro.cornell.edu [Jet Propulsion Laboratory, MS 183-900, California Institute of Technology, Pasadena, CA 91109 (United States)

    2014-08-10

    Infrared spectra of carbon-rich objects that have evolved off the asymptotic giant branch reveal a range of dust properties, including fullerenes, polycyclic aromatic hydrocarbons (PAHs), aliphatic hydrocarbons, and several unidentified features, including the 21 μm emission feature. To test for the presence of fullerenes, we used the position and width of the feature at 18.7-18.9 μm and examined other features at 17.4 and 6-9 μm. This method adds three new fullerene sources to the known sample, but it also calls into question three previous identifications. We confirm that the strong 11 μm features seen in some sources arise primarily from SiC, which may exist as a coating around carbonaceous cores and result from photo-processing. Spectra showing the 21 μm feature usually show the newly defined Class D PAH profile at 7-9 μm. These spectra exhibit unusual PAH profiles at 11-14 μm, with weak contributions at 12.7 μm, which we define as Class D1, or show features shifted to ∼11.4, 12.4, and 13.2 μm, which we define as Class D2. Alkyne hydrocarbons match the 15.8 μm feature associated with 21 μm emission. Sources showing fullerene emission but no PAHs have blue colors in the optical, suggesting a clear line of sight to the central source. Spectra with 21 μm features and Class D2 PAH emission also show photometric evidence for a relatively clear line of sight to the central source. The multiple associations of the 21 μm feature with aliphatic hydrocarbons suggest that the carrier is related to this material in some way.

  14. Carbon-rich dust past the asymptotic giant branch: Aliphatics, aromatics, and fullerenes in the Magellanic Clouds

    International Nuclear Information System (INIS)

    Sloan, G. C.; Lagadec, E.; Zijlstra, A. A.; Kraemer, K. E.; Weis, A. P.; Matsuura, M.; Volk, K.; Peeters, E.; Cami, J.; Duley, W. W.; Bernard-Salas, J.; Kemper, F.; Sahai, R.

    2014-01-01

    Infrared spectra of carbon-rich objects that have evolved off the asymptotic giant branch reveal a range of dust properties, including fullerenes, polycyclic aromatic hydrocarbons (PAHs), aliphatic hydrocarbons, and several unidentified features, including the 21 μm emission feature. To test for the presence of fullerenes, we used the position and width of the feature at 18.7-18.9 μm and examined other features at 17.4 and 6-9 μm. This method adds three new fullerene sources to the known sample, but it also calls into question three previous identifications. We confirm that the strong 11 μm features seen in some sources arise primarily from SiC, which may exist as a coating around carbonaceous cores and result from photo-processing. Spectra showing the 21 μm feature usually show the newly defined Class D PAH profile at 7-9 μm. These spectra exhibit unusual PAH profiles at 11-14 μm, with weak contributions at 12.7 μm, which we define as Class D1, or show features shifted to ∼11.4, 12.4, and 13.2 μm, which we define as Class D2. Alkyne hydrocarbons match the 15.8 μm feature associated with 21 μm emission. Sources showing fullerene emission but no PAHs have blue colors in the optical, suggesting a clear line of sight to the central source. Spectra with 21 μm features and Class D2 PAH emission also show photometric evidence for a relatively clear line of sight to the central source. The multiple associations of the 21 μm feature with aliphatic hydrocarbons suggest that the carrier is related to this material in some way.

  15. Supramolecular Allosteric Cofacial Porphyrin Complexes

    International Nuclear Information System (INIS)

    Oliveri, Christopher G.; Gianneschi, Nathan C.; Nguyen, Son Binh T.; Mirkin, Chad A.; Stern, Charlotte L.; Wawrzak, Zdzislaw; Pink, Maren

    2008-01-01

    Nature routinely uses cooperative interactions to regulate cellular activity. For years, chemists have designed synthetic systems that aim toward harnessing the reactivity common to natural biological systems. By learning how to control these interactions in situ, one begins to allow for the preparation of man-made biomimetic systems that can efficiently mimic the interactions found in Nature. To this end, we have designed a synthetic protocol for the preparation of flexible metal-directed supramolecular cofacial porphyrin complexes which are readily obtained in greater than 90% yield through the use of new hemilabile porphyrin ligands with bifunctional ether-phosphine or thioether-phosphine substituents at the 5 and 15 positions on the porphyrin ring. The resulting architectures contain two hemilabile ligand-metal domains (Rh I or Cu I sites) and two cofacially aligned porphyrins (Zn II sites), offering orthogonal functionalities and allowing these multimetallic complexes to exist in two states, 'condensed' or 'open'. Combining the ether-phosphine ligand with the appropriate Rh I or Cu I transition-metal precursors results in 'open' macrocyclic products. In contrast, reacting the thioether-phosphine ligand with RhI or CuI precursors yields condensed structures that can be converted into their 'open' macrocyclic forms via introduction of additional ancillary ligands. The change in cavity size that occurs allows these structures to function as allosteric catalysts for the acyl transfer reaction between X-pyridylcarbinol (where X = 2, 3, or 4) and 1-acetylimidazole. For 3- and 4-pyridylcarbinol, the 'open' macrocycle accelerates the acyl transfer reaction more than the condensed analogue and significantly more than the porphyrin monomer. In contrast, an allosteric effect was not observed for 2-pyridylcarbinol, which is expected to be a weaker binder and is unfavorably constrained inside the macrocyclic cavity.

  16. Extreme alkali bicarbonate- and carbonate-rich fluid inclusions in granite pegmatite from the Precambrian Rønne granite, Bornholm Island, Denmark

    Science.gov (United States)

    Thomas, Rainer; Davidson, Paul; Schmidt, Christian

    2011-02-01

    Our study of fluid and melt inclusions in quartz and feldspar from granite pegmatite from the Precambrian Rønne granite, Bornholm Island, Denmark revealed extremely alkali bicarbonate- and carbonate-rich inclusions. The solid phases (daughter crystals) are mainly nahcolite [NaHCO3], zabuyelite [Li2CO3], and in rare cases potash [K2CO3] in addition to the volatile phases CO2 and aqueous carbonate/bicarbonate solution. Rare melt inclusions contain nahcolite, dawsonite [NaAl(CO3)(OH)2], and muscovite. In addition to fluid and melt inclusions, there are primary CO2-rich vapor inclusions, which mostly contain small nahcolite crystals. The identification of potash as a naturally occurring mineral would appear to be the first recorded instance. From the appearance of high concentrations of these carbonates and bicarbonates, we suggest that the mineral-forming media were water- and alkali carbonate-rich silicate melts or highly concentrated fluids. The coexistence of silicate melt inclusions with carbonate-rich fluid and nahcolite-rich vapor inclusions indicates a melt-melt-vapor equilibrium during the crystallization of the pegmatite. These results are supported by the results of hydrothermal diamond anvil cell experiments in the pseudoternary system H2O-NaHCO3-SiO2. Additionally, we show that boundary layer effects were insignificant in the Bornholm pegmatites and are not required for the origin of primary textures in compositionally simple pegmatites at least.

  17. Design of Molecular Materials: Supramolecular Engineering

    Science.gov (United States)

    Simon, Jacques; Bassoul, Pierre

    2001-02-01

    This timely and fascinating book is destined to be recognised as THE book on supramolecular engineering protocols. It covers this sometimes difficult subject in an approachable form, gathering together information from many sources. Supramolecular chemistry, which links organic chemistry to materials science, is one of the fastest growth areas of chemistry research. This book creates a correlation between the structure of single molecules and the physical and chemical properties of the resulting materials. By making systematic changes to the component molecules, the resulting solid can be engineered for optimum performance. There is a clearly written development from synthesis of designer molecules to properties of solids and further on to devices and complex materials systems, providing guidelines for mastering the organisation of these systems. Topics covered include: Systemic chemistry Molecular assemblies Notions of symmetry Supramolecular engineering Principe de Curie Organisation in molecular media Molecular semiconductors Industrial applications of molecular materials This superb book will be invaluable to researchers in the field of supramolecular materials and also to students and teachers of the subject.

  18. Strong and Reversible Monovalent Supramolecular Protein Immobilization

    NARCIS (Netherlands)

    Young, Jacqui F.; Nguyen, Hoang D.; Yang, Lanti; Huskens, Jurriaan; Jonkheijm, Pascal; Brunsveld, Luc

    2010-01-01

    Proteins with an iron clasp: Site-selective incorporation of a ferrocene molecule into a protein allows for easy, strong, and reversible supramolecular protein immobilization through a selective monovalent interaction of the ferrocene with a cucurbit[7]uril immobilized on a gold surface. The

  19. Supramolecular Liquid Crystal Displays Construction and Applications

    OpenAIRE

    Hoogboom, J.T.V.

    2004-01-01

    This thesis describes chemical methodologies, which can be ued to construct alignment layers for liquid crystal display purposes in a non-clean room environment, by making use of supramolecular chemistry. These techniques are subsequently used to attain control over LCD-properties, both pre- and post-LCD construction. In addition, the thesis describes the application of LCD technology in biosensors.

  20. Engineering responsive supramolecular biomaterials: Toward smart therapeutics.

    Science.gov (United States)

    Webber, Matthew J

    2016-09-01

    Engineering materials using supramolecular principles enables generalizable and modular platforms that have tunable chemical, mechanical, and biological properties. Applying this bottom-up, molecular engineering-based approach to therapeutic design affords unmatched control of emergent properties and functionalities. In preparing responsive materials for biomedical applications, the dynamic character of typical supramolecular interactions facilitates systems that can more rapidly sense and respond to specific stimuli through a fundamental change in material properties or characteristics, as compared to cases where covalent bonds must be overcome. Several supramolecular motifs have been evaluated toward the preparation of "smart" materials capable of sensing and responding to stimuli. Triggers of interest in designing materials for therapeutic use include applied external fields, environmental changes, biological actuators, applied mechanical loading, and modulation of relative binding affinities. In addition, multistimuli-responsive routes can be realized that capture combinations of triggers for increased functionality. In sum, supramolecular engineering offers a highly functional strategy to prepare responsive materials. Future development and refinement of these approaches will improve precision in material formation and responsiveness, seek dynamic reciprocity in interactions with living biological systems, and improve spatiotemporal sensing of disease for better therapeutic deployment.

  1. On the Interior of Carbon-Rich Exoplanets: New Insight from Si-C System at Ultra High Pressure

    Science.gov (United States)

    Miozzi Ferrini, F.; Morard, G.; Antonangeli, D.; Clark, A. N.; Edmund, E.; Fiquet, G.; Mezouar, M.

    2017-12-01

    The variability in the mass/radius ratio of the more than 3200 exoplanets discovered so far, is a direct consequence of the large diversity of their internal composition. Exoplanets with a mass between 1 and 10 times the mass of the Earth are typically referred to as super-Earths, and their mineralogical composition depends on that of the protoplanetary disk. The key variable in determining the chemical makeup of such planets is the C/O ratio. Values of C/O ratio smaller than 0.8 correspond to an interior dominated by silicates (e.g. terrestrial planets), whereas for C/O ratios > 0.8 the interior is enriched in carbon. In these C-rich planets, Si may form carbides instead of silicates (Duffy et al., 2015). The detection of planet 55 Cancri e, with a particularly high C/O ratio, has increased the interest in carbon-rich planets. 55 Cancri e has been modelled as a layered structure made by different assemblages of carbon, silicon and iron (Madhusudan et al., 2012). However, the accuracy of such type of models suffers the lack of experimental data on the Si - C system at extreme conditions of pressure and temperature. Experimental equations of state are limited to 80 GPa (Nisr et al., 2017) and little is known about subsolidus relation, with only one theoretical study from Wilson and Militzer (2004) at multi-megabar pressures. Here we present experiments on SiC samples by synchrotron X-ray diffraction, in laser heated diamond anvil cell between 30-200 GPa and 300-3500 K. The results show evidences of coexistence of SiC with Si or C, without the appearance of intermediate compounds. Moreover, between 60 and 75 GPa, SiC undergoes a phase transition from the zinc blend structure (B3), to the rock salt structure (B1). This phase transition, also reported in previous literature work (e.g. Daviau and Lee, 2017), corresponds to a change in the atoms coordination, and is accompanied by an important volume reduction. Acknowledgements: This work was supported by the ERC Planet

  2. Uranium and Cesium sorption to bentonite colloids in high salinity and carbonate-rich environments: Implications for radionuclide transport

    Science.gov (United States)

    Tran, E. L.; Teutsch, N.; Klein-BenDavid, O.; Weisbrod, N.

    2017-12-01

    When radionuclides are leaked into the subsurface due to engineered waste disposal container failure, the ultimate barrier to migration of radionuclides into local aquifers is sorption to the surrounding rock matrix and sediments, which often includes a bentonite backfill. The extent of this sorption is dependent on pH, ionic strength, surface area availability, radionuclide concentration, surface mineral composition, and solution chemistry. Colloidal-sized bentonite particles eroded from the backfill have been shown to facilitate the transport of radionuclides sorbed to them away from their source. Thus, sorption of radionuclides such as uranium and cesium to bentonite surfaces can be both a mobilization or retardation factor. Though numerous studies have been conducted to-date on sorption of radionuclides under low ionic strength and carbonate-poor conditions, there has been little research conducted on the behavior of radionuclides in high salinities and carbonate rich conditions typical of aquifers in the vicinity of some potential nuclear repositories. This study attempts to characterize the sorption properties of U(VI) and Cs to bentonite colloids under these conditions using controlled batch experiments. Results indicated that U(VI) undergoes little to no sorption to bentonite colloids in a high-salinity (TDS= 9000 mg/L) artificial groundwater. This lack of sorption was attributed to the formation of CaUO2(CO3)22- and Ca2UO2(CO3)3 aqueous ions which stabilize the UO22+ ions in solution. In contrast, Cs exhibited greater sorption, the extent to which was influenced greatly by the matrix water's ionic strength and the colloid concentration used. Surprisingly, when both U and Cs were together, the presence of U(VI) in solution decreased Cs sorption, possibly due to the formation of stabilizing CaUO2(CO3)22- anions. The implications of this research are that rather than undergoing colloid-facilitated transport, U(VI) is expected to migrate similarly to a

  3. Incorporation and Effects of Nanoparticles in a Supramolecular Polymer

    Science.gov (United States)

    2016-05-01

    polymerizations and main-chain supramolecular polymers . Macromolecules. 2009;42:6823–6835. 17. Wojtecki RJ, Meador MA, Rowan SJ. Using the dynamic bond...ARL-TR-7687 ● MAY 2016 US Army Research Laboratory Incorporation and Effects of Nanoparticles in a Supramolecular Polymer by...Laboratory Incorporation and Effects of Nanoparticles in a Supramolecular Polymer by Alice M Savage Oak Ridge Institute of Science and Education

  4. Supramolecular interactions in the solid state

    Directory of Open Access Journals (Sweden)

    Giuseppe Resnati

    2015-11-01

    Full Text Available In the last few decades, supramolecular chemistry has been at the forefront of chemical research, with the aim of understanding chemistry beyond the covalent bond. Since the long-range periodicity in crystals is a product of the directionally specific short-range intermolecular interactions that are responsible for molecular assembly, analysis of crystalline solids provides a primary means to investigate intermolecular interactions and recognition phenomena. This article discusses some areas of contemporary research involving supramolecular interactions in the solid state. The topics covered are: (1 an overview and historical review of halogen bonding; (2 exploring non-ambient conditions to investigate intermolecular interactions in crystals; (3 the role of intermolecular interactions in morphotropy, being the link between isostructurality and polymorphism; (4 strategic realisation of kinetic coordination polymers by exploiting multi-interactive linker molecules. The discussion touches upon many of the prerequisites for controlled preparation and characterization of crystalline materials.

  5. Iodide, azide, and cyanide complexes of (N,C), (N,N), and (N,O) metallacycles of tetra- and pentavalent uranium

    International Nuclear Information System (INIS)

    Benaud, Olivier; Berthet, Jean-Claude; Thuery, Pierre; Ephritikhine, Michel

    2011-01-01

    In contrast to the neutral macrocycle [UN* 2 (N,C)] (1) [N* = N(SiMe 3 ) 3 ; N,C = CH 2 SiMe 2 N-(SiMe 3 )] which was quite inert toward I 2 , the anionic bismetallacycle [NaUN*(N,C) 2 ] (2) was readily transformed into the enlarged monometallacycle [UN*(N,N)I] (4) [N,N = (Me 3 Si)NSiMe 2 CH 2 CH 2 SiMe 2 N(SiMe 3 )] resulting from C-C coupling of the two CH 2 groups, and [NaUN*(N,O) 2 ] (3) [N,O = OC(=CH 2 )SiMe 2 N(SiMe 3 )], which is devoid of any U-C bond, was oxidized into the UV bismetallacycle [Na{UN*(N,O) 2 }2(μ-I)] (5). Sodium amalgam reduction of 4 gave the U(III) compound [UN*(N,N)] (6). Addition of MN 3 or MCN to the (N,C), (N,N), and (N,O) metallacycles 1, 4, and 5 led to the formation of the anionic azide or cyanide derivatives M[UN* 2 (N,C)(N 3 )] [M = Na, 7a or Na(15-crown-5), 7b], M[UN* 2 (N,C)(CN)] [M = NEt 4 , 8a or Na(15-crown-5), 8b or K(18-crown-6), 8c], M[UN*(N,N)(N 3 ) 2 ] [M = Na, 9a or Na(THF)4, 9b], [NEt 4 ][UN*(N,N)(CN) 2 ] (10), M[UN*(N,O) 2 (N 3 )] [M = Na, 11a or Na(15-crown-5), 11b], M[UN*(N,O) 2 (CN)] [M = NEt 4 , 12a or Na(15-crown-5), 12b]. In the presence of excess iodine in THF, the cyanide 12a was converted back into the iodide 5, while the azide 11a was transformed into the neutral UV complex [U(N{SiMe 3 }-SiMe 2 C{CHI}O) 2 I(THF)] (13). The X-ray crystal structures of 4, 7b, 8a-c, 9b, 10, 12b, and 13 were determined. (authors)

  6. Uses of neutron scattering in supramolecular chemistry

    International Nuclear Information System (INIS)

    Lindoy, L.F.

    1998-01-01

    Full text: A major thrust in recent chemical research has been the development of supramolecular chemistry 1 - broadly the chemistry of large multicomponent molecular assemblies in which the component structural units are held together by either covalent linkages or by a variety of weaker (non-covalent) interactions that include hydrogen bonding, dipole stacking, π-stacking, van der Waals q forces and favourable hydrophobic interactions. Much of the activity in the area has been motivated by the known behaviour of biological molecules (such as enzymes). Thus molecular assemblies are ubiquitous in natural systems but, with a limited number of exceptions, have only recently been the subject of increasing investigation by chemists. A feature of much of this recent work has been its focus on molecular design for achieving complementarity between single molecule hosts and guests. The use of single crystal neutron diffraction coupled with molecular modelling and a range of other techniques to investigate the nature of individual supramolecular systems will be discussed. By way of example, in one such study the supramolecular array formed by co-crystallisation of 1,2- diaminoethane and benzoic acid has been investigated; the system self-assembles into an unusual layered structure composed of two-dimensional hydrogen bonded networks sandwiched between layers of edge-to-face stacked aromatic systems. The number of hydrogen-bond donors and acceptors is balanced in this structure

  7. Supramolecular gel electrophoresis of large DNA fragments.

    Science.gov (United States)

    Tazawa, Shohei; Kobayashi, Kazuhiro; Oyoshi, Takanori; Yamanaka, Masamichi

    2017-10-01

    Pulsed-field gel electrophoresis is a frequent technique used to separate exceptionally large DNA fragments. In a typical continuous field electrophoresis, it is challenging to separate DNA fragments larger than 20 kbp because they migrate at a comparable rate. To overcome this challenge, it is necessary to develop a novel matrix for the electrophoresis. Here, we describe the electrophoresis of large DNA fragments up to 166 kbp using a supramolecular gel matrix and a typical continuous field electrophoresis system. C 3 -symmetric tris-urea self-assembled into a supramolecular hydrogel in tris-boric acid-EDTA buffer, a typical buffer for DNA electrophoresis, and the supramolecular hydrogel was used as a matrix for electrophoresis to separate large DNA fragments. Three types of DNA marker, the λ-Hind III digest (2 to 23 kbp), Lambda DNA-Mono Cut Mix (10 to 49 kbp), and Marker 7 GT (10 to 165 kbp), were analyzed in this study. Large DNA fragments of greater than 100 kbp showed distinct mobility using a typical continuous field electrophoresis system. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Supramolecular Pharmaceutical Sciences: A Novel Concept Combining Pharmaceutical Sciences and Supramolecular Chemistry with a Focus on Cyclodextrin-Based Supermolecules.

    Science.gov (United States)

    Higashi, Taishi; Iohara, Daisuke; Motoyama, Keiichi; Arima, Hidetoshi

    2018-01-01

    Supramolecular chemistry is an extremely useful and important domain for understanding pharmaceutical sciences because various physiological reactions and drug activities are based on supramolecular chemistry. However, it is not a major domain in the pharmaceutical field. In this review, we propose a new concept in pharmaceutical sciences termed "supramolecular pharmaceutical sciences," which combines pharmaceutical sciences and supramolecular chemistry. This concept could be useful for developing new ideas, methods, hypotheses, strategies, materials, and mechanisms in pharmaceutical sciences. Herein, we focus on cyclodextrin (CyD)-based supermolecules, because CyDs have been used not only as pharmaceutical excipients or active pharmaceutical ingredients but also as components of supermolecules.

  9. Supramolecular Nanoparticles for Molecular Diagnostics and Therapeutics

    Science.gov (United States)

    Chen, Kuan-Ju

    Over the past decades, significant efforts have been devoted to explore the use of various nanoparticle-based systems in the field of nanomedicine, including molecular imaging and therapy. Supramolecular synthetic approaches have attracted lots of attention due to their flexibility, convenience, and modularity for producing nanoparticles. In this dissertation, the developmental story of our size-controllable supramolecular nanoparticles (SNPs) will be discussed, as well as their use in specific biomedical applications. To achieve the self-assembly of SNPs, the well-characterized molecular recognition system (i.e., cyclodextrin/adamantane recognition) was employed. The resulting SNPs, which were assembled from three molecular building blocks, possess incredible stability in various physiological conditions, reversible size-controllability and dynamic disassembly that were exploited for various in vitro and in vivo applications. An advantage of using the supramolecular approach is that it enables the convenient incorporation of functional ligands onto SNP surface that confers functionality ( e.g., targeting, cell penetration) to SNPs. We utilized SNPs for molecular imaging such as magnetic resonance imaging (MRI) and positron emission tomography (PET) by introducing reporter systems (i.e., radio-isotopes, MR contrast agents, and fluorophores) into SNPs. On the other hand, the incorporation of various payloads, including drugs, genes and proteins, into SNPs showed improved delivery performance and enhanced therapeutic efficacy for these therapeutic agents. Leveraging the powers of (i) a combinatorial synthetic approach based on supramolecular assembly and (ii) a digital microreactor, a rapid developmental pathway was developed that is capable of screening SNP candidates for the ideal structural and functional properties that deliver optimal performance. Moreover, SNP-based theranostic delivery systems that combine reporter systems and therapeutic payloads into a

  10. Supramolecular materials based on hydrogen-bonded polymers

    NARCIS (Netherlands)

    ten Brinke, Gerrit; Ruokolainen, Janne; Ikkala, Olli; Binder, W

    2007-01-01

    Combining supramolecular principles with block copolymer self-assembly offers unique possibilities to create materials with responsive and/or tunable properties. The present chapter focuses on supramolecular materials based on hydrogen bonding and (block co-) polymers. Several cases will be

  11. Temperature-Induced, Selective Assembly of Supramolecular Colloids in Water

    NARCIS (Netherlands)

    Van Ravensteijn, Bas G.P.; Vilanova, Neus; De Feijter, Isja; Kegel, Willem K.; Voets, Ilja K.

    2017-01-01

    In this article, we report the synthesis and physical characterization of colloidal polystyrene particles that carry water-soluble supramolecular N,N′,N″,-trialkyl-benzene-1,3,5-tricarboxamides (BTAs) on their surface. These molecules are known to assemble into one-dimensional supramolecular

  12. Directed supramolecular surface assembly of SNAP-tag fusion proteins

    NARCIS (Netherlands)

    Uhlenheuer, D.A.; Wasserberg, D.; Haase, C.; Nguyen, H.; Schenkel, J.H.; Huskens, J.; Ravoo, B.J.; Jonkheijm, P.; Brunsveld, L.

    2012-01-01

    Supramolecular assembly of proteins on surfaces and vesicles was investigated by site-selective incorporation of a supramolecular guest element on proteins. Fluorescent proteins were site-selectively labeled with bisadamantane by SNAP-tag technology. The assembly of the bisadamantane functionalized

  13. Supramolecular biomaterials : a modular approach towards tissue engineering

    NARCIS (Netherlands)

    Dankers, P.Y.W.; Meijer, E.W.

    2007-01-01

    Supramolecular chemistry is an exciting area of science that plays a central role in bringing different disciplines together, ranging from molecular medicine to nanotechnology. Materials science based on supramolecular interactions is an emerging field, which has made important steps forward in the

  14. Dynamic reciprocity in bio-inspired supramolecular materials

    NARCIS (Netherlands)

    Bastings, M.M.C.

    2012-01-01

    Dynamic reciprocity, the spatio-temporal bidirectional process between evolving partners in a functional system is not only found in nature, but also applies to supramolecularly assembling architectures. In this thesis, the focus was on the understanding of nature-inspired supramolecular

  15. Directed Supramolecular Surface Assembly of SNAP-tag Fusion Proteins

    NARCIS (Netherlands)

    Uhlenheuer, D.A.; Wasserberg, D.; Haase, C.; Nguyen, Hoang D.; Schenkel, J.H.; Huskens, Jurriaan; Ravoo, B.J.; Jonkheijm, Pascal; Brunsveld, Luc

    2012-01-01

    Supramolecular assembly of proteins on surfaces and vesicles was investigated by site-selective incorporation of a supramolecular guest element on proteins. Fluorescent proteins were site-selectively labeled with bisadamantane by SNAP-tag technology. The assembly of the bisadamantane functionalized

  16. Gelation induced supramolecular chirality: chirality transfer, amplification and application.

    Science.gov (United States)

    Duan, Pengfei; Cao, Hai; Zhang, Li; Liu, Minghua

    2014-08-14

    Supramolecular chirality defines chirality at the supramolecular level, and is generated from the spatial arrangement of component molecules assembling through non-covalent interactions such as hydrogen bonding, van der Waals interactions, π-π stacking, hydrophobic interactions and so on. During the formation of low molecular weight gels (LMWGs), one kind of fascinating soft material, one frequently encounters the phenomenon of chirality as well as chiral nanostructures, either from chiral gelators or even achiral gelators. A view of gelation-induced supramolecular chirality will be very helpful to understand the self-assembly process of the gelator molecules as well as the chiral structures, the regulation of the chirality in the gels and the development of the "smart" chiral materials such as chiroptical devices, catalysts and chiral sensors. It necessitates fundamental understanding of chirality transfer and amplification in these supramolecular systems. In this review, recent progress in gelation-induced supramolecular chirality is discussed.

  17. Epoxy resin-inspired reconfigurable supramolecular networks

    OpenAIRE

    Balkenende Diederik; Olson Rebecca; Balog Sandor; Weder Christoph; Montero de Espinosa Lucas

    2016-01-01

    With the goal to push the mechanical properties of reconfigurable supramolecular polymers toward those of thermoset resins we prepared and investigated a new family of hydrogen bonded polymer networks that are assembled from isophthalic acid terminated oligo(bisphenol A co epichlorohydrin) and different bipyridines. These materials display high storage moduli of up to 3.9 GPa can be disassembled upon heating to form melts with a viscosity of as low as 2.1 Pa·s and fully reassemble upon coolin...

  18. Synthesis, spectroscopy, thermal studies and supramolecular ...

    Indian Academy of Sciences (India)

    TECS

    Synthesis, spectroscopy, thermal studies and supramolecular structures of two .... J = 9 Hz), 8∙13 (d, 2H, J = 9 Hz), 7∙69 (s, 1H), 7∙04. (s, 2H). ... 1H NMR (D2O): δ (in ppm); 8∙05 (d, 2H, ..... 86∙33 (2). 86∙92(1). 87∙08(2). V (Ε3). 553∙1(6). 573∙71(5). 561∙56(14). 557∙5(3) .... Mn, Co and Ni complexes.28–30 The observed inter-.

  19. Leaching Characteristics of Uranium And Copper from Their Mineralization in the Carbonate Rich latosol of Abu-Thor Locality, South Western Sinai, Egypt

    International Nuclear Information System (INIS)

    El-Sheikh, E.M.; Ghazala, R.A.; Abdelwarith, A.; Salem, F.; Ali, S.

    2015-01-01

    The chemical processing of the poly-mineralized carbonate rich latosol ore occurring at Abu-Thor locality of south western Sinai area has been studied for the recovery of uranium and copper metal values. A technological sample assaying 700 ppm U and 9.7% Cu was collected. In the present study, two successive percolation leaching procedures were performed after determination of optimum leaching factors by agitation leaching process. The first was carried out for uranium recovery by using urea as organic leaching agent which was possible to achieve leaching efficiency exceeding 90.3%. This procedure was followed by a second one for copper recovery using ammonium hydroxide solution and ammonium carbonate. The obtained dissolution efficiency was about 93%. The leached metal values namely U and Cu from the studied ore were then extracted as marketable products in the form of ammonium diuranate and copper sulphate, respectively.

  20. 3D Printing Polymers with Supramolecular Functionality for Biological Applications.

    Science.gov (United States)

    Pekkanen, Allison M; Mondschein, Ryan J; Williams, Christopher B; Long, Timothy E

    2017-09-11

    Supramolecular chemistry continues to experience widespread growth, as fine-tuned chemical structures lead to well-defined bulk materials. Previous literature described the roles of hydrogen bonding, ionic aggregation, guest/host interactions, and π-π stacking to tune mechanical, viscoelastic, and processing performance. The versatility of reversible interactions enables the more facile manufacturing of molded parts with tailored hierarchical structures such as tissue engineered scaffolds for biological applications. Recently, supramolecular polymers and additive manufacturing processes merged to provide parts with control of the molecular, macromolecular, and feature length scales. Additive manufacturing, or 3D printing, generates customizable constructs desirable for many applications, and the introduction of supramolecular interactions will potentially increase production speed, offer a tunable surface structure for controlling cell/scaffold interactions, and impart desired mechanical properties through reinforcing interlayer adhesion and introducing gradients or self-assembled structures. This review details the synthesis and characterization of supramolecular polymers suitable for additive manufacture and biomedical applications as well as the use of supramolecular polymers in additive manufacturing for drug delivery and complex tissue scaffold formation. The effect of supramolecular assembly and its dynamic behavior offers potential for controlling the anisotropy of the printed objects with exquisite geometrical control. The potential for supramolecular polymers to generate well-defined parts, hierarchical structures, and scaffolds with gradient properties/tuned surfaces provides an avenue for developing next-generation biomedical devices and tissue scaffolds.

  1. Supramolecular assembly of organic bicapped Keggin polyoxometalate

    International Nuclear Information System (INIS)

    Han Zhangang; Zhao Yulong; Peng Jun; Ma Huiyuan; Liu Qun; Wang Enbo; Hu Ninghai

    2004-01-01

    Two novel supramolecular assemblies of organic bicapped Keggin polyoxometalates (pbpy) 8 H 3 [PW 12 O 40 ]·2H 2 O (1) and (pbpy) 4 H[PMo 12 O 40 (VO)] (2) (pbpy=5-phenyl-2-(4-pyridinyl)pyridine) have been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction. Crystallographic data for compound (1), C 128 H 103 N 16 O 42 PW 12 , triclinic, space group P1-bar: a=13.4759(8) A, b=14.6395(11) A, c=16.5743(10) A, α=95.764(2) deg., β=102.166(2) deg., γ=92.9870(10) deg., Z=1, V=3171.1(4) A 3 ; for compound (2), C 64 H 49 N 8 O 41 PMo 12 V, triclinic, space group P1-bar: a=11.5377(11) A, b=12.7552(8) A, c=14.9599(10) A, α=72.270(4) deg., β=88.916(2) deg., γ=67.865(4) deg., Z=1, V=1931.0(3) A 3 . X-ray analyses show that both 1 and 2 represent rare organic bicapped Keggin structures and are supported by supramolecular interactions to extend into a 3D framework. In particular, the unusual structure feature of compound 2 contains a simultaneously organic and inorganic capped structure

  2. Cellular uptake: lessons from supramolecular organic chemistry.

    Science.gov (United States)

    Gasparini, Giulio; Bang, Eun-Kyoung; Montenegro, Javier; Matile, Stefan

    2015-07-04

    The objective of this Feature Article is to reflect on the importance of established and emerging principles of supramolecular organic chemistry to address one of the most persistent problems in life sciences. The main topic is dynamic covalent chemistry on cell surfaces, particularly disulfide exchange for thiol-mediated uptake. Examples of boronate and hydrazone exchange are added for contrast, comparison and completion. Of equal importance are the discussions of proximity effects in polyions and counterion hopping, and more recent highlights on ring tension and ion pair-π interactions. These lessons from supramolecular organic chemistry apply to cell-penetrating peptides, particularly the origin of "arginine magic" and the "pyrenebutyrate trick," and the currently emerging complementary "disulfide magic" with cell-penetrating poly(disulfide)s. They further extend to the voltage gating of neuronal potassium channels, gene transfection, and the delivery of siRNA. The collected examples illustrate that the input from conceptually innovative chemistry is essential to address the true challenges in biology beyond incremental progress and random screening.

  3. Structural aspects, thermal behavior, and stability of a self-assembled supramolecular polymer derived from flunixin-meglumine supramolecular adducts

    Energy Technology Data Exchange (ETDEWEB)

    Cassimiro, Douglas L.; Kobelnik, Marcelo [Institute of Chemistry, Paulista State University, Av. Prof. Francisco Degni, s/n, 14800-900 Araraquara, Sao Paulo (Brazil); Ribeiro, Clovis A., E-mail: ribeiroc@iq.unesp.br [Institute of Chemistry, Paulista State University, Av. Prof. Francisco Degni, s/n, 14800-900 Araraquara, Sao Paulo (Brazil); Crespi, Marisa S.; Boralle, Nivaldo [Institute of Chemistry, Paulista State University, Av. Prof. Francisco Degni, s/n, 14800-900 Araraquara, Sao Paulo (Brazil)

    2012-02-10

    Highlights: Black-Right-Pointing-Pointer The thermal behavior of flunixin-meglumine, a potent NSAID, was investigated. Black-Right-Pointing-Pointer This supramolecular adduct self-assembled resulting in a polymer-like material. Black-Right-Pointing-Pointer The supramolecular polymer showed a high molecular weight around 290 {+-} 88 MDa. Black-Right-Pointing-Pointer NMR and FT-IR showed that hydrogen bonding can be responsible for the self-assembly. Black-Right-Pointing-Pointer The stability of the supramolecular polymer was also studied and presented here. - Abstract: Flunixin-meglumine, a potent non-steroidal anti-inflammatory drug (NSAID) and a cyclo-oxygenase inhibitor for Veterinary use, is a hydrogen-bonded supramolecular adduct. Two monotropically related crystalline modifications (Forms I and II) were observed for a flunixin-meglumine sample. During the melt of form I, flunixin-meglumine adducts self-assembled by hydrogen bonds involving the hydroxyl groups from meglumine, resulting in an amorphous rigid glassy supramolecular polymer, which showed a high molecular weight around 290 {+-} 88 MDa and a glass transition around 49.5 Degree-Sign C. Both the adduct and the resulting supramolecular polymer were characterized by differential scanning calorimetry (DSC), nuclear magnetic resonance spectroscopy (NMR), Fourier transform-infrared spectroscopy (FT-IR), and weight-average molecular weight determination by light scattering. The chemical stability and morphological changes of the depolymerization process were also investigated for the supramolecular polymer, by DSC and scanning electron microscopy (SEM), respectively.

  4. Programming supramolecular biohybrids as precision therapeutics.

    Science.gov (United States)

    Ng, David Yuen Wah; Wu, Yuzhou; Kuan, Seah Ling; Weil, Tanja

    2014-12-16

    CONSPECTUS: Chemical programming of macromolecular structures to instill a set of defined chemical properties designed to behave in a sequential and precise manner is a characteristic vision for creating next generation nanomaterials. In this context, biopolymers such as proteins and nucleic acids provide an attractive platform for the integration of complex chemical design due to their sequence specificity and geometric definition, which allows accurate translation of chemical functionalities to biological activity. Coupled with the advent of amino acid specific modification techniques, "programmable" areas of a protein chain become exclusively available for any synthetic customization. We envision that chemically reprogrammed hybrid proteins will bridge the vital link to overcome the limitations of synthetic and biological materials, providing a unique strategy for tailoring precision therapeutics. In this Account, we present our work toward the chemical design of protein- derived hybrid polymers and their supramolecular responsiveness, while summarizing their impact and the advancement in biomedicine. Proteins, in their native form, represent the central framework of all biological processes and are an unrivaled class of macromolecular drugs with immense specificity. Nonetheless, the route of administration of protein therapeutics is often vastly different from Nature's biosynthesis. Therefore, it is imperative to chemically reprogram these biopolymers to direct their entry and activity toward the designated target. As a consequence of the innate structural regularity of proteins, we show that supramolecular interactions facilitated by stimulus responsive chemistry can be intricately designed as a powerful tool to customize their functions, stability, activity profiles, and transportation capabilities. From another perspective, a protein in its denatured, unfolded form serves as a monodispersed, biodegradable polymer scaffold decorated with functional side

  5. Zwitterionic supramolecular nanoparticles: self-assembly and responsive properties

    NARCIS (Netherlands)

    Stoffelen, C.; Huskens, Jurriaan

    2015-01-01

    Supramolecular nanoparticles (SNPs) are of high interest in both nanoscience and molecular diagnostics and therapeutics, because of their reversible and designable properties. To ensure colloidal stabilization and biocompatibility, most reported strategies require the use of hydrophilic long-chain

  6. Magnetic structure of two- and three-dimensional supramolecular compounds

    Energy Technology Data Exchange (ETDEWEB)

    Decurtins, S.; Schmalle, H.W.; Pellaux, R. [Zurich Univ. (Switzerland); Fischer, P.; Fauth, F. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Ouladdiaf, B. [Institut Max von Laue - Paul Langevin, 75 - Paris (France)

    1997-09-01

    Supramolecular chiral networks of oxalato-bridged transition metals show either two- or three-dimensional structural features. The magnetic structures of such compounds have been investigated by means of elastic neutron powder diffraction. (author) 2 figs., 2 refs.

  7. Host-guest supramolecular nanosystems for cancer diagnostics and therapeutics.

    Science.gov (United States)

    Wang, Lei; Li, Li-li; Fan, Yun-shan; Wang, Hao

    2013-07-26

    Extensive efforts have been devoted to the construction of functional supramolecular nanosystems for applications in catalysis, energy conversion, sensing and biomedicine. The applications of supramolecular nanosystems such as liposomes, micelles, inorganic nanoparticles, carbon materials for cancer diagnostics and therapeutics have been reviewed by other groups. Here, we will focus on the recent momentous advances in the implementation of typical supramolecular hosts (i.e., cyclodextrins, calixarenes, cucurbiturils and metallo-hosts) and their nanosystems in cancer diagnostics and therapeutics. We discuss the evolutive process of supramolecular nanosystems from the structural control and characterization to their diagnostic and therapeutic function exploitation and even the future potentials for clinical translation. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Supramolecular photochemistry of drugs in biomolecular environments.

    Science.gov (United States)

    Monti, Sandra; Manet, Ilse

    2014-06-21

    In this tutorial review we illustrate how the interaction of photoactive drugs/potential drugs with proteins or DNA in supramolecular complexes can determine the course of the reactions initiated by the drug absorbed photons, evidencing the mechanistic differences with respect to the solution conditions. We focus on photoprocesses, independent of oxygen, that lead to chemical modification of the biomolecules, with formation of new covalent bonds or cleavage of existing bonds. Representative systems are mainly selected from the literature of the last decade. The photoreactivity of some aryl propionic acids, (fluoro)quinolones, furocoumarins, metal coordination complexes, quinine-like compounds, naphthaleneimides and pyrenyl-peptides with proteins or DNA is discussed. The use of light for biomolecule photomodification, historically relevant to biological photosensitization processes and some forms of photochemotherapy, is nowadays becoming more and more important in the development of innovative methods in nanomedicine and biotechnology.

  9. Chemistry of supramolecular systems containing porphyrins and metal complexes

    OpenAIRE

    Araki, Koiti; Toma, Henrique Eisi

    2002-01-01

    Supramolecular chemistry is expected to keep a high developing pace in the next years, giving support to the advancement of molecular devices and nanotechnology. In this sense, porphyrins and their analogues should play a significant role as a consequence of their catalytic, electrocatalytic, photochemical and photoelectrochemical properties. In this review we focused on our own strategy based on coordination chemistry for the design and build-up of supermolecules and supramolecular structure...

  10. Supramolecular Complexes Formed in Systems Bile Salt-Bilirubin-Silica

    Science.gov (United States)

    Vlasova, N. N.; Severinovskaya, O. V.; Golovkova, L. P.

    The formation of supramolecular complexes between bilirubin and primary micelles of bile salts has been studied. The association constants of bile salts and binding of bilirubin with these associates have been determined. The adsorption of bilirubin and bile salts from individual and mixed aqueous solutions onto hydrophobic silica surfaces has been investigated. The interaction of bilirubin with primary bile salt micelles and the strong retention in mixed micelles, which are supramolecular complexes, result in the adsorption of bilirubin in free state only.

  11. Construction of Supramolecular Architectures via Self-assembly

    Institute of Scientific and Technical Information of China (English)

    Takeharu; Haino

    2007-01-01

    1 Results In this paper we report supramolecular polymeric nano networks formed by the molecular-recognition-directed self-assembly between a calix[5]arene and C60[1]. Covalently-linked double-calix[5]arenes take up C60 into their cavities[2]. This complementary interaction creates a strong non-covalent bonding; thus,the iterative self-assembly between dumbbell fullerene 1 and ditopic host 2 can produce the supramolecular polymer networks (See Fig.1).

  12. A 200 year sedimentary record of progressive eutrophication in lake Greifen (Switzerland): Implications for the origin of organic-carbon-rich sediments

    Science.gov (United States)

    Hollander, David J.; McKenzie, Judith A.; Lo Ten Haven, H.

    1992-09-01

    Over the past 200 years Lake Greifen, a small lake in northeastern Switzerland, has undergone dramatic changes in primary productivity and eutrophication due to increased nutrient supply from agricultural activity and industrialization. A 40 year historical record of the water-column chemistry indicates that productivity and eutrophication reached a maximum in 1974, after which stricter regulations on the input of nutrients resulted in a progressive decrease. Collected cores show the sedimentary expression of this anthropogenically induced eutrophication by a well-developed annual sedimentation and by enhanced values of total organic carbon, organic-carbon accumulation rates, and hydrogen indices (HI) of the kerogens. Analyses of the carbon isotopic composition of sedimentary carbonates and organic matter reveal that the fractionation between these two phases varies with the HI of kerogens. This observation is explicable in terms of changing productivity and preservation of the organic matter, and the CO2(aq) budget of the water body. We propose that if high primary productivity were primarily responsible for the preservation and accumulation of organic matter, then a negative correlation will occur between Δδ13Ccalcite-organic matter (Δδ13Ccal-om) and HI values. In an environment with relatively low to moderate productivity but with bottom-water anoxia, a positive correlation will exist between Δδ13Ccal-om and HI values. This study of Lake Greifen has implications for understanding paleoenvironmental controls on ancient organic-carbon-rich sediments.

  13. HERSCHEL /HIFI OBSERVATIONS OF IRC+10216: WATER VAPOR IN THE INNER ENVELOPE OF A CARBON-RICH ASYMPTOTIC GIANT BRANCH STAR

    International Nuclear Information System (INIS)

    Neufeld, David A.; Gonzalez-Alfonso, Eduardo; Melnick, Gary J.; Szczerba, Ryszard; Schmidt, Miroslaw; Decin, Leen; De Koter, Alex; Schoeier, Fredrik; Cernicharo, Jose

    2011-01-01

    We report the results of observations of 10 rotational transitions of water vapor toward the carbon-rich asymptotic giant branch (AGB) star IRC+10216 (CW Leonis), carried out with Herschel's HIFI instrument. Each transition was securely detected by means of observations using the dual beam switch mode of HIFI. The measured line ratios imply that water vapor is present in the inner outflow at small distances (≤few x 10 14 cm) from the star, confirming recent results reported by Decin et al. from observations with Herschel's PACS and SPIRE instruments. This finding definitively rules out the hypothesis that the observed water results from the vaporization of small icy objects in circular orbits. The origin of water within the dense C-rich envelope of IRC+10216 remains poorly understood. We derive upper limits on the H 17 2 O/H 16 2 O and H 18 2 O/H 16 2 O isotopic abundance ratios of ∼5 x 10 -3 (3σ), providing additional constraints on models for the origin of the water vapor in IRC+10216.

  14. Constitutional dynamic chemistry: bridge from supramolecular chemistry to adaptive chemistry.

    Science.gov (United States)

    Lehn, Jean-Marie

    2012-01-01

    Supramolecular chemistry aims at implementing highly complex chemical systems from molecular components held together by non-covalent intermolecular forces and effecting molecular recognition, catalysis and transport processes. A further step consists in the investigation of chemical systems undergoing self-organization, i.e. systems capable of spontaneously generating well-defined functional supramolecular architectures by self-assembly from their components, thus behaving as programmed chemical systems. Supramolecular chemistry is intrinsically a dynamic chemistry in view of the lability of the interactions connecting the molecular components of a supramolecular entity and the resulting ability of supramolecular species to exchange their constituents. The same holds for molecular chemistry when the molecular entity contains covalent bonds that may form and break reversibility, so as to allow a continuous change in constitution by reorganization and exchange of building blocks. These features define a Constitutional Dynamic Chemistry (CDC) on both the molecular and supramolecular levels.CDC introduces a paradigm shift with respect to constitutionally static chemistry. The latter relies on design for the generation of a target entity, whereas CDC takes advantage of dynamic diversity to allow variation and selection. The implementation of selection in chemistry introduces a fundamental change in outlook. Whereas self-organization by design strives to achieve full control over the output molecular or supramolecular entity by explicit programming, self-organization with selection operates on dynamic constitutional diversity in response to either internal or external factors to achieve adaptation.The merging of the features: -information and programmability, -dynamics and reversibility, -constitution and structural diversity, points to the emergence of adaptive and evolutive chemistry, towards a chemistry of complex matter.

  15. Solid-phase based synthesis of ureidopyrimidinone-peptide conjugates for supramolecular biomaterials

    NARCIS (Netherlands)

    Feijter, de I.; Goor, O.J.G.M.; Hendrikse, S.I.S.; Comellas Aragones, M.; Sontjens, S.H.M.; Zaccaria, S.; Fransen, P.P.K.H.; Peeters, J.W.; Milroy, L.G.; Dankers, P.Y.W.

    2015-01-01

    Supramolecular polymers have shown to be powerful scaffolds for tissue engineering applications. Supramolecular biomaterials functionalized with ureidopyrimidinone (UPy) moieties, which dimerize via quadruple hydrogen-bond formation, are eminently suitable for this purpose. The conjugation of the

  16. Multifunctional, supramolecular, continuous artificial nacre fibres

    Science.gov (United States)

    Hu, Xiaozhen; Xu, Zhen; Gao, Chao

    2012-10-01

    Nature has created amazing materials during the process of evolution, inspiring scientists to studiously mimic them. Nacre is of particular interest, and it has been studied for more than half-century for its strong, stiff, and tough attributes resulting from the recognized ``brick-and-mortar'' (B&M) layered structure comprised of inorganic aragonite platelets and biomacromolecules. The past two decades have witnessed great advances in nacre-mimetic composites, but they are solely limited in films with finite size (centimetre-scale). To realize the adream target of continuous nacre-mimics with perfect structures is still a great challenge unresolved. Here, we present a simple and scalable strategy to produce bio-mimic continuous fibres with B&M structures of alternating graphene sheets and hyperbranched polyglycerol (HPG) binders via wet-spinning assembly technology. The resulting macroscopic supramolecular fibres exhibit excellent mechanical properties comparable or even superior to nacre and bone, and possess fine electrical conductivity and outstanding corrosion-resistance.

  17. Dual responsive supramolecular hydrogel with electrochemical activity.

    Science.gov (United States)

    Du, Ping; Liu, Jianghua; Chen, Guosong; Jiang, Ming

    2011-08-02

    Supramolecular materials with reversible responsiveness to environmental changes are of particular research interest in recent years. Inclusion complexation between cyclodextrin (CD) and ferrocene (Fc) is well-known and extensively studied because of its reversible association-dissociation controlled by the redox state of Fc. Although there are quite a few reported nanoscale materials incorporating this host-guest pair, polymeric hydrogels with electrochemical activity based on this interactive pair are still rare. Taking advantage of our previous reported hybrid inclusion complex (HIC) hydrogel structure, a new Fc-HIC was designed and obtained with β-CD-modified quantum dots as the core and Fc-ended diblock co-polymer p(DMA-b-NIPAM) as the shell, to achieve an electrochemically active hydrogel at elevated temperatures. Considering the two independent cross-linking strategies in the network structure, i.e., the interchain aggregation of pNIPAM and inclusion complexation between CD and Fc on the surface of the quantum dots, the hydrogel was fully thermo-reversible and its gel-sol transition was achieved after the addition of either an oxidizing agent or a competitive guest to Fc.

  18. Reversible Guest Exchange Mechanisms in Supramolecular Host-GuestAssemblies

    Energy Technology Data Exchange (ETDEWEB)

    Pluth, Michael D.; Raymond, Kenneth N.

    2006-09-01

    Synthetic chemists have provided a wide array of supramolecular assemblies able to encapsulate guest molecules. The scope of this tutorial review focuses on supramolecular host molecules capable of reversibly encapsulating polyatomic guests. Much work has been done to determine the mechanism of guest encapsulation and guest release. This review covers common methods of monitoring and characterizing guest exchange such as NMR, UV-VIS, mass spectroscopy, electrochemistry, and calorimetry and also presents representative examples of guest exchange mechanisms. The guest exchange mechanisms of hemicarcerands, cucurbiturils, hydrogen-bonded assemblies, and metal-ligand assemblies are discussed. Special attention is given to systems which exhibit constrictive binding, a motif common in supramolecular guest exchange systems.

  19. COMPARATIVE SPECTRA OF OXYGEN-RICH VERSUS CARBON-RICH CIRCUMSTELLAR SHELLS: VY CANIS MAJORIS AND IRC +10216 AT 215-285 GHz

    International Nuclear Information System (INIS)

    Tenenbaum, E. D.; Dodd, J. L.; Woolf, N. J.; Ziurys, L. M.; Milam, S. N.

    2010-01-01

    A sensitive (1σ rms at 1 MHz resolution ∼3 mK) 1 mm spectral line survey (214.5-285.5 GHz) of VY Canis Majoris (VY CMa) and IRC +10216 has been conducted to compare the chemistries of oxygen- and carbon-rich circumstellar envelopes. This study was carried out using the Submillimeter Telescope of the Arizona Radio Observatory with a new Atacama Large Millimeter Array type receiver. This survey is the first to chemically characterize an O-rich circumstellar shell at millimeter wavelengths. In VY CMa, 128 emission features were detected arising from 18 different molecules; and in IRC +10216, 720 lines were observed, assigned to 32 different species. The 1 mm spectrum of VY CMa is dominated by SO 2 and SiS; in IRC +10216, C 4 H and SiC 2 are the most recurrent species. Ten molecules were common to both sources: CO, SiS, SiO, CS, CN, HCN, HNC, NaCl, PN, and HCO + . Sulfur plays an important role in VY CMa, but saturated/unsaturated carbon dominates the molecular content of IRC +10216, producing CH 2 NH, for example. Although the molecular complexity of IRC +10216 is greater, VY CMa supports a unique 'inorganic' chemistry leading to the oxides PO, AlO, and AlOH. Only diatomic and triatomic compounds were observed in VY CMa, while species with four or more atoms are common in IRC +10216, reflecting carbon's ability to form multiple strong bonds, unlike oxygen. In VY CMa, a new water maser (v 2 = 2) has been found, as well as vibrationally excited NaCl. Toward IRC +10216, vibrationally excited CCH was detected for the first time.

  20. Comparative Spectra of Oxygen-rich Versus Carbon-rich Circumstellar Shells: VY Canis Majoris and IRC +10216 at 215-285 GHz

    Science.gov (United States)

    Tenenbaum, E. D.; Dodd, J. L.; Milam, S. N.; Woolf, N. J.; Ziurys, L. M.

    2010-09-01

    A sensitive (1σ rms at 1 MHz resolution ~3 mK) 1 mm spectral line survey (214.5-285.5 GHz) of VY Canis Majoris (VY CMa) and IRC +10216 has been conducted to compare the chemistries of oxygen- and carbon-rich circumstellar envelopes. This study was carried out using the Submillimeter Telescope of the Arizona Radio Observatory with a new Atacama Large Millimeter Array type receiver. This survey is the first to chemically characterize an O-rich circumstellar shell at millimeter wavelengths. In VY CMa, 128 emission features were detected arising from 18 different molecules; and in IRC +10216, 720 lines were observed, assigned to 32 different species. The 1 mm spectrum of VY CMa is dominated by SO2 and SiS; in IRC +10216, C4H and SiC2 are the most recurrent species. Ten molecules were common to both sources: CO, SiS, SiO, CS, CN, HCN, HNC, NaCl, PN, and HCO+. Sulfur plays an important role in VY CMa, but saturated/unsaturated carbon dominates the molecular content of IRC +10216, producing CH2NH, for example. Although the molecular complexity of IRC +10216 is greater, VY CMa supports a unique "inorganic" chemistry leading to the oxides PO, AlO, and AlOH. Only diatomic and triatomic compounds were observed in VY CMa, while species with four or more atoms are common in IRC +10216, reflecting carbon's ability to form multiple strong bonds, unlike oxygen. In VY CMa, a new water maser (v 2 = 2) has been found, as well as vibrationally excited NaCl. Toward IRC +10216, vibrationally excited CCH was detected for the first time.

  1. Comparative Spectra of Oxygen-Rich Versus Carbon-Rich Circumstellar Shells: VY Canis Majoris and IRC(plus)10216 at 215-285 GHz

    Science.gov (United States)

    Tenebaum, E. D.; Dodd, J. L.; Milam, S. N.; Woolf, N. J.; Ziurys, L. M.

    2010-01-01

    A sensitive (1sigma rms at 1 MHz resolution approx.3 mK) 1 mm spectral line survey (214.5-285.5 GHz) of VY Canis Majoris (VY CMa) and IRC +10216 has been conducted to compare the chemistries of oxygen- and carbon-rich circumstellar envelopes. This study was carried out using the Submillimeter Telescope of the Arizona Radio Observatory with a new Atacama Large Millimeter Array type receiver. This survey is the first to chemically characterize an O-rich circumstellar shell at millimeter wavelengths. In VY CMa, 128 emission features were detected arising from 18 different molecules; and in IRC +10216, 720 lines were observed, assigned to 32 different species. The 1 mm spectrum of VY CMa is dominated by SO, and SiS; in IRC +10216, C4H and SiC2 are the most recurrent species. Ten molecules were common to both sources: CO, SiS, SiO, CS, CN, HCN, HNC, NaCl, PN, and HCO(+). Sulfur plays an important role in VY CMa, but saturated/ unsaturated carbon dominates the molecular content of IRC +102.16, producing CH2NH, for example. Although the molecular complexity of IRC +10216 is greater, VY CMa supports a unique "inorganic" chemistry leading to the oxides PO, AlO, and AlOH. Only diatomic and triatomic compounds were observed in VY CMa, while species with four or more atoms are common in IRC +10216, reflecting carbon's ability to form multiple strong bonds, unlike oxygen. In VY CMa, a new water maser (v2 = 2) has been found, as well as vibrationally excited NaCl. Toward IRC +10216, vibrationally excited CCH was detected for the first time.

  2. Structural and chemical degradation mechanisms of pure YSZ and its components ZrO2 and Y2O3 in carbon-rich fuel gases.

    Science.gov (United States)

    Köck, Eva-Maria; Kogler, Michaela; Götsch, Thomas; Klötzer, Bernhard; Penner, Simon

    2016-05-25

    Structural and chemical degradation mechanisms of metal-free yttria stabilized zirconia (YSZ-8, 8 mol% Y2O3 in ZrO2) in comparison to its pure oxidic components ZrO2 and Y2O3 have been studied in carbon-rich fuel gases with respect to coking/graphitization and (oxy)carbide formation. By combining operando electrochemical impedance spectroscopy (EIS), operando Fourier-transform infrared (FT-IR) spectroscopy and X-ray photoelectron spectroscopy (XPS), the removal and suppression of CH4- and CO-induced carbon deposits and of those generated in more realistic fuel gas mixtures (syngas, mixtures of CH4 or CO with CO2 and H2O) was examined under SOFC-relevant conditions up to 1273 K and ambient pressures. Surface-near carbidization is a major problem already on the "isolated" (i.e. Nickel-free) cermet components, leading to irreversible changes of the conduction properties. Graphitic carbon deposition takes place already on the "isolated" oxides under sufficiently fuel-rich conditions, most pronounced in the pure gases CH4 and CO, but also significantly in fuel gas mixtures containing H2O and CO2. For YSZ, a comparative quantification of the total amount of deposited carbon in all gases and mixtures is provided and thus yields favorable and detrimental experimental approaches to suppress the carbon formation. In addition, the effectivity and reversibility of removal of the coke/graphite layers was comparably studied in the pure oxidants O2, CO2 and H2O and their effective contribution upon addition to the pure fuel gases CO and CH4 verified.

  3. Supramolecular interactions of oxidative stress biomarker glutathione with fluorone black

    Science.gov (United States)

    Hepel, Maria; Stobiecka, Magdalena

    2018-03-01

    Oxidative stress biomarkers, including glutathione (GSH) and related compounds, are involved in a variety of interactions enabling redox potential maintenance in living cells and protection against radicals. Since the oxidative stress is promoting and, in many cases, inducing serious illnesses, monitoring of GSH levels can aid in diagnostics and disease prevention. Herein, we report on the discovery of the formation of a supramolecular ensemble of GSH with fluorone black (9-phenyl fluorone, FB) which is optically active and enables sensitive determination of GSH by resonance elastic light scattering (RELS). We have found that supramolecular interactions of GSH with FB can be probed with spectroscopic, RELS, and electrochemical methods. Our investigations show that RELS intensity for FB solutions increases with GSH concentration while fluorescence emission of FB is not affected, as quenching begins only above 0.8 mM GSH. The UV-Vis difference spectra show a positive peak at 383 nm and a negative peak at 458 nm, indicating a higher-energy absorbing complex in comparison to the non-bonded FB host. Supramolecular interactions of FB with GSH have also been corroborated by electrochemical measurements involving two configurations of FB-GSH ensembles on electrodes: (i) an inverted orientation on Au-coated quartz crystal piezoelectrode (Au@SG-FB), with strong thiolate bonding to gold, and (ii) a non-inverted orientation on glassy carbon electrode (GCE@FB-GS), with weak π-π stacking attachment and efficient charge mediation through the ensemble. The formation of a supramolecular ensemble with hydrogen bonding has also been confirmed by quantum mechanical calculations. The discovery of supramolecular FB-GSH ensemble formation enables elucidating the mechanisms of strong RELS responses, changes in UV-Vis absorption spectra, and the electrochemical reactivity. Also, it provides new insights to the understanding of the efficient charge-transfer in redox potential homeostasis

  4. Supramolecular architectures constructed using angular bipyridyl ligands

    International Nuclear Information System (INIS)

    Barnett, Sarah Ann

    2003-01-01

    This work details the synthesis and characterization of a series of coordination frameworks that are formed using bidentate angular N-donor ligands. Pyrimidine was reacted with metal(ll) nitrate salts. Reactions using Cd(NO 3 ) 2 receive particular focus and the analogous reactions using the linear ligand, pyrazine, were studied for comparison. In all cases, two-dimensional coordination networks were prepared. Structural diversity is observed for the Cd(ll) centres including metal-nitrate bridging. In contrast, first row transition metal nitrates form isostructural one-dimensional chains with only the bridging N-donor ligands generating polymeric propagation. The angular ligand, 2,4-bis(4-pyridyl)-1,3,5-triazine (dpt), was reacted with Cd(NO 3 ) 2 and Zn(NO 3 ) 2 . Whereas Zn(NO 3 ) 2 compounds exhibit solvent mediated polymorphism, a range of structures were obtained for the reactions with Cd(NO 3 ) 2 , including the first example of a doubly parallel interpenetrated 4.8 2 net. 4,7-phenanthroline, was reacted with various metal(ll) nitrates as well as cobalt(ll) and copper(ll) halides. The ability of 4,7-phenanthroline to act as both a N-donor ligand and a hydrogen bond acceptor has been discussed. Reactions of CuSCN with pyrimidine yield an unusual three-dimensional structure in which polymeric propagation is not a result of ligand bridging. The reaction of CuSCN with dpt yielded structural supramolecular isomers. (author)

  5. Supramolecular structures constructed from three novel rare earth ...

    Indian Academy of Sciences (India)

    Supramolecular structures constructed from three novel rare earth metal complexes. HUAZE DONGa,∗, XIAOJUN FENGb,∗, XIA LIUc, BIN ZHENGa, JIANHONG BIa, YAN XUEa,. SHAOHUA GOUd and YANPING WANGa. aDepartment of Chemistry and Chemical Engineering, Hefei Normal University, Hefei 230061, China.

  6. From steroids to aqueous supramolecular chemistry: an autobiographical career review.

    Science.gov (United States)

    Gibb, Bruce C

    2016-01-01

    The focus of my group's research is aqueous supramolecular chemistry; we try to understand how chemical entities interact with water and consequently how they interact with each other. This personal history recounts my career experiences that led to his involvement with this fascinating area of science.

  7. Fabrication of supramolecular frameworks by tuning the binding site ...

    Indian Academy of Sciences (India)

    Administrator

    Fabrication of supramolecular frameworks by tuning the binding site of a tripodal ligand with d. 10 metal ions 803. Table 1. Crystal data and structure refinement parameters for 1 and 2. 1 .... e-mail: deposit@ccdc.cam.ac.uk web: http://www. ccdc. cam.ac.uk/deposit]. Supplementary figures and tables can be found in website ...

  8. Rotation of a single molecule within a supramolecular bearing

    DEFF Research Database (Denmark)

    Gimzewski, J.K.; Joachim, C.; Schlittler, R.R.

    1998-01-01

    Experimental visualization and verification of a single-molecule rotor operating within a supramolecular bearing is reported. Using a scanning tunneling microscope, single molecules were observed to exist in one of two spatially defined states Laterally separated by 0.26 nanometers. One...

  9. Reversible optical transcription of supramolecular chirality into molecular chirality

    NARCIS (Netherlands)

    Jong, Jaap J.D. de; Lucas, Linda N.; Kellogg, Richard M.; Esch, Jan H. van; Feringa, Bernard

    2004-01-01

    In nature, key molecular processes such as communication, replication, and enzyme catalysis all rely on a delicate balance between molecular and supramolecular chirality. Here we report the design, synthesis, and operation of a reversible, photoresponsive, self-assembling molecular system in which

  10. Autoamplification of molecular chirality through the induction of supramolecular chirality

    NARCIS (Netherlands)

    van Dijken, Derk Jan; Beierle, John M.; Stuart, Marc C. A.; Szymanski, Wiktor; Browne, Wesley R.; Feringa, Ben L.

    2014-01-01

    The novel concept for the autoamplification of molecular chirality, wherein the amplification proceeds through the induction of supramolecular chirality, is presented. A solution of prochiral, ring-open diarylethenes is doped with a small amount of their chiral, ring-closed counterpart. The

  11. Size-controlled and redox-responsive supramolecular nanoparticles

    NARCIS (Netherlands)

    Weinhart-Mejia, R.; Kronig, G.A.; Huskens, Jurriaan

    2015-01-01

    Control over the assembly and disassembly of nanoparticles is pivotal for their use as drug delivery vehicles. Here, we aim to form supramolecular nanoparticles (SNPs) by combining advantages of the reversible assembly properties of SNPs using host–guest interactions and of a stimulus-responsive

  12. Double Dynamic Supramolecular Polymers of Covalent Oligo-Dynamers

    NARCIS (Netherlands)

    Schaeffer, Gaël; Buhler, Eric; Candau, Sauveur Jean; Lehn, Jean-Marie

    2013-01-01

    Double-dynamic polymers, incorporating both molecular and supramolecular dynamic features (“double dynamers”) have been generated, where these functions are present in a nonstoichiometric ratio in the main chain of the polymer. It has been achieved by (1) the formation of covalent oligo-dynamers in

  13. Switchable charge injection barrier in an organic supramolecular semiconductor

    NARCIS (Netherlands)

    Gorbunov, A.V.; Haedler, A.T.; Putzeys, T.; Zha, R.H.; Schmidt, H.W.; Kivala, M.; Urbanavičiutec, I.; Wübbenhorst, M.; Meijer, E.W.; Kemerink, M.

    2016-01-01

    We disclose a supramolecular material that combines semiconducting and dipolar functionalities. The material consists of a discotic semiconducting carbonyl-bridged triarylamine core, which is surrounded by three dipolar amide groups. In thin films, the material self-organizes in a hexagonal columnar

  14. Monosaccharides as Versatile Units for Water-Soluble Supramolecular Polymers.

    Science.gov (United States)

    Leenders, Christianus M A; Jansen, Gijs; Frissen, Martijn M M; Lafleur, René P M; Voets, Ilja K; Palmans, Anja R A; Meijer, E W

    2016-03-18

    We introduce monosaccharides as versatile water-soluble units to compatibilise supramolecular polymers based on the benzene-1,3,5-tricarboxamide (BTA) moiety with water. A library of monosaccharide-based BTAs is evaluated, varying the length of the alkyl chain (hexyl, octyl, decyl and dodecyl) separating the BTA and saccharide units, as well as the saccharide units (α-glucose, β-glucose, α-mannose and α-galactose). In all cases, the monosaccharides impart excellent water compatibility. The length of the alkyl chain is the determining factor to obtain either long, one-dimensional supramolecular polymers (dodecyl spacer), small aggregates (decyl spacer) or molecularly dissolved (octyl and hexyl) BTAs in water. For the BTAs comprising a dodecyl spacer, our results suggest that a cooperative self-assembly process is operative and that the introduction of different monosaccharides does not significantly change the self- assembly behaviour. Finally, we investigate the potential of post-assembly functionalisation of the formed supramolecular polymers by taking advantage of dynamic covalent bond formation between the monosaccharides and benzoxaboroles. We observe that the supramolecular polymers readily react with a fluorescent benzoxaborole derivative permitting imaging of these dynamic complexes by confocal fluorescence microscopy. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Evaporation rate-based selection of supramolecular chirality.

    Science.gov (United States)

    Hattori, Shingo; Vandendriessche, Stefaan; Koeckelberghs, Guy; Verbiest, Thierry; Ishii, Kazuyuki

    2017-03-09

    We demonstrate the evaporation rate-based selection of supramolecular chirality for the first time. P-type aggregates prepared by fast evaporation, and M-type aggregates prepared by slow evaporation are kinetic and thermodynamic products under dynamic reaction conditions, respectively. These findings provide a novel solution reaction chemistry under the dynamic reaction conditions.

  16. A Supramolecular Approach to Medicinal Chemistry: Medicine Beyond the Molecule

    Science.gov (United States)

    Smith, David K.

    2005-03-01

    This article focuses on the essential roles played by intermolecular forces in mediating the interactions between chemical molecules and biological systems. Intermolecular forces constitute a key topic in chemistry programs, yet can sometimes seem disconnected from real-life applications. However, by taking a "supramolecular" view of medicinal chemistry and focusing on interactions between molecules, it is possible to come to a deeper understanding of recent developments in medicine. This allows us to gain a real insight into the interface between biology and chemistry—an interdisciplinary area that is crucial for the development of modern medicinal products. This article emphasizes a conceptual view of medicinal chemistry, which has important implications for the future, as the supramolecular approach to medicinal-chemistry products outlined here is rapidly allowing nanotechnology to converge with medicine. In particular, this article discusses recent developments including the rational design of drugs such as Relenza and Tamiflu, the mode of action of vancomycin, and the mechanism by which bacteria develop resistance, drug delivery using cyclodextrins, and the importance of supramolecular chemistry in understanding protein aggregation diseases such as Alzheimer's and Creutzfield Jacob. The article also indicates how taking a supramolecular approach will enable the development of new nanoscale medicines.

  17. Synthesis and crystal structure of a wheel-shaped supramolecular ...

    Indian Academy of Sciences (India)

    41-218/2012 (SR)), India for financial support. DG and BS thank the Council of Scientific and Indus- trial Research (CSIR) for Senior Research Fellowship. We are grateful to Perkin-Elmer for ESI-Mass analysis. References. 1. (a) Lehn J M 1995 In Supramolecular Chem- istry, Concepts and Perspectives (Weinheim: VCH);.

  18. From supramolecular polymers to multi-component biomaterials.

    Science.gov (United States)

    Goor, Olga J G M; Hendrikse, Simone I S; Dankers, Patricia Y W; Meijer, E W

    2017-10-30

    The most striking and general property of the biological fibrous architectures in the extracellular matrix (ECM) is the strong and directional interaction between biologically active protein subunits. These fibers display rich dynamic behavior without losing their architectural integrity. The complexity of the ECM taking care of many essential properties has inspired synthetic chemists to mimic these properties in artificial one-dimensional fibrous structures with the aim to arrive at multi-component biomaterials. Due to the dynamic character required for interaction with natural tissue, supramolecular biomaterials are promising candidates for regenerative medicine. Depending on the application area, and thereby the design criteria of these multi-component fibrous biomaterials, they are used as elastomeric materials or hydrogel systems. Elastomeric materials are designed to have load bearing properties whereas hydrogels are proposed to support in vitro cell culture. Although the chemical structures and systems designed and studied today are rather simple compared to the complexity of the ECM, the first examples of these functional supramolecular biomaterials reaching the clinic have been reported. The basic concept of many of these supramolecular biomaterials is based on their ability to adapt to cell behavior as a result of dynamic non-covalent interactions. In this review, we show the translation of one-dimensional supramolecular polymers into multi-component functional biomaterials for regenerative medicine applications.

  19. Comparison of Cellulose Supramolecular Structures Between Nanocrystals of Different Origins

    Science.gov (United States)

    Umesh P. Agarwal; Richard S. Reiner; Christopher G. Hunt; Jeffery Catchmark; E. Johan Foster; Akira Isogai

    2015-01-01

    In this study, morphologies and supramolecular structures of CNCs from wood-pulp, cotton, bacteria, tunicate, and cladophora were investigated. TEM was used to study the morphological aspects of the nanocrystals whereas Raman spectroscopy provided information on the cellulose molecular structure and its organization within a CNC. Dimensional differences between the...

  20. Intelligent Chiral Sensing Based on Supramolecular and Interfacial Concepts

    Directory of Open Access Journals (Sweden)

    Hironori Izawa

    2010-07-01

    Full Text Available Of the known intelligently-operating systems, the majority can undoubtedly be classed as being of biological origin. One of the notable differences between biological and artificial systems is the important fact that biological materials consist mostly of chiral molecules. While most biochemical processes routinely discriminate chiral molecules, differentiation between chiral molecules in artificial systems is currently one of the challenging subjects in the field of molecular recognition. Therefore, one of the important challenges for intelligent man-made sensors is to prepare a sensing system that can discriminate chiral molecules. Because intermolecular interactions and detection at surfaces are respectively parts of supramolecular chemistry and interfacial science, chiral sensing based on supramolecular and interfacial concepts is a significant topic. In this review, we briefly summarize recent advances in these fields, including supramolecular hosts for color detection on chiral sensing, indicator-displacement assays, kinetic resolution in supramolecular reactions with analyses by mass spectrometry, use of chiral shape-defined polymers, such as dynamic helical polymers, molecular imprinting, thin films on surfaces of devices such as QCM, functional electrodes, FET, and SPR, the combined technique of magnetic resonance imaging and immunoassay, and chiral detection using scanning tunneling microscopy and cantilever technology. In addition, we will discuss novel concepts in recent research including the use of achiral reagents for chiral sensing with NMR, and mechanical control of chiral sensing. The importance of integration of chiral sensing systems with rapidly developing nanotechnology and nanomaterials is also emphasized.

  1. [Special impact of supramolecular chemistry on Chinese medicine theories].

    Science.gov (United States)

    He, Fu-Yuan; Zhou, Yi-Qun; Deng, Kai-Wen; Deng, Jun-Lin; Shi, Ji-Lian; Liu, Wen-Long; Yang, Yan-Tao; Tang, Yu; Liu, Zhi-Gang

    2014-04-01

    The paper aimed to elucidate the specific impact of supramolecular chemistry on the Chinese medicine theories (CMT) in their modernization, after had summarized up the research status of supramolecular chemistry and analyzed the possible supramolecular forms of Chinese medicine (CM), as well as considered the problems in modernization of CM theories. On comparison of the classical chemistry that delt with chemical bonds among atoms, the supramolecular chemistry was rather concerned with varietes of weak noncovalent bonds intermolecules, and reflected the macro-apparent chemical properties of each molecules, and was the most appropriate chemical theories to explain the CMT and microcosmic materials. The molecules in the human body and Chinese material medica (CMM) formed supramolecules by way of self-assembly, self-organization, self-recognition and self-replication, with themselves or with complexation, composition, chelation, inclusion, neutralization etc. Meridian and Zang-fu viscera in CMT might be a space channel structure continuously consisted of unique molecules cavity that was imprinted with the supramolecularly template inside and outside of cells, through which the molecules in CMM interacted with the meridian and Zang-fu viscera. When small molecules in human body imprinted with macromolecules in meridian and Zang-fu viscera, in other words, they migrated along within imprinting channels of meridian and Zang-fu viscera on behavior of "Qi chromatography" impulsed by the heart beat, finally showed up on macroscopic the anisotropy of tissue and organ, as described namely as visceral manifestation in Chinese medical science. When small molecules in CMM interacted with imprinting channel on meridian and Zang-fu viscera, the natural properties and efficacy regularities of CMM was reflected on macroscopic. Therefore, the special representation forms of basic CMT is based on the macroscopic expression of "Qi chromatography" abided by imprinting effect

  2. Supramolecular interactions of oxidative stress biomarker glutathione with fluorone black.

    Science.gov (United States)

    Hepel, Maria; Stobiecka, Magdalena

    2018-03-05

    Oxidative stress biomarkers, including glutathione (GSH) and related compounds, are involved in a variety of interactions enabling redox potential maintenance in living cells and protection against radicals. Since the oxidative stress is promoting and, in many cases, inducing serious illnesses, monitoring of GSH levels can aid in diagnostics and disease prevention. Herein, we report on the discovery of the formation of a supramolecular ensemble of GSH with fluorone black (9-phenyl fluorone, FB) which is optically active and enables sensitive determination of GSH by resonance elastic light scattering (RELS). We have found that supramolecular interactions of GSH with FB can be probed with spectroscopic, RELS, and electrochemical methods. Our investigations show that RELS intensity for FB solutions increases with GSH concentration while fluorescence emission of FB is not affected, as quenching begins only above 0.8mM GSH. The UV-Vis difference spectra show a positive peak at 383nm and a negative peak at 458nm, indicating a higher-energy absorbing complex in comparison to the non-bonded FB host. Supramolecular interactions of FB with GSH have also been corroborated by electrochemical measurements involving two configurations of FB-GSH ensembles on electrodes: (i) an inverted orientation on Au-coated quartz crystal piezoelectrode (Au@SG-FB), with strong thiolate bonding to gold, and (ii) a non-inverted orientation on glassy carbon electrode (GCE@FB-GS), with weak π-π stacking attachment and efficient charge mediation through the ensemble. The formation of a supramolecular ensemble with hydrogen bonding has also been confirmed by quantum mechanical calculations. The discovery of supramolecular FB-GSH ensemble formation enables elucidating the mechanisms of strong RELS responses, changes in UV-Vis absorption spectra, and the electrochemical reactivity. Also, it provides new insights to the understanding of the efficient charge-transfer in redox potential homeostasis

  3. Application of the principle of supramolecular chemistry in the fields of radiochemistry and radiation chemistry

    International Nuclear Information System (INIS)

    Shen Xinghai; Chen Qingde; Gao Hongcheng

    2008-01-01

    Supramolecular chemistry, one of the front fields in chemistry, is defined as 'chemistry beyond the molecule', bearing on the organized entities of higher complexity that result from the association of two or more chemical species held together by intermolecular forces. This article focuses on the application of the principle of supramolecular chemistry in the fields of radiochemistry and radiation chemistry. The following aspects are concerned: (1) the recent progress of supramolecular chemistry; (2) the application of the principle of supramolecular chemistry and the functions of supramolecular system, i.e., recognition, assembly and translocation, in the extraction of nuclides; (3) the application of microemulsion, ionic imprinted polymers, ionic liquids and cloud point extraction in the enrichment of nuclides; (4) the radiation effect of supramolecular systems. (authors)

  4. Estratégia supramolecular para a nanotecnologia Supramolecular approach to nanotechnology

    Directory of Open Access Journals (Sweden)

    Koiti Araki

    2007-12-01

    Full Text Available Brazilian science is evolving rapidly and steadly in the last 10 years, reaching the 15º place in the international ranking. Research in nanotechnology is following a similar way generating new scientific and technological knowledge in several frontiers but specially in the interfaces of two or more areas, where Chemistry is consolidating itself as a central science. In this context, the supramolecular approach is a very promissing one because it allows the build-up of a chemical inteligence using all the sistematized knowledge for the design and development of new nanomaterials and products. The great challenge of Chemistry is not decrease the dimensionality of the materials but instead find ways to increase the dimensionality and structural complexity keeping strict control on the interactions between the components, in order to generate materials with new properties and functionalities. Unfortunately, the current vigorous advancement of scientific research has not been followed by the transformation of such know-how into patents and produts. Therefore much efforts should be devoted to build a national science and technology program, joining all the segments of the society involved in the technological development (university, institutes of technological research, industry and government in order to promote the furtherance of the Brazilian technological base. Only in this way it is possible to evolve to a technological society capable to transform the scientific knowledge into wealthy, thus sustaining the socioeconomic development of the country.

  5. A polyamidoamine dendrimer-streptavidin supramolecular architecture for biosensor development.

    Science.gov (United States)

    Soda, N; Arotiba, O A

    2017-12-01

    A novel polyamidoamine dendrimer-streptavidin supramolecular architecture suitable as a versatile platform for biosensor development is reported. The dendrimer was electrodeposited on a glassy carbon electrode via cyclic voltammetry. The dendrimer electrode was further modified with streptavidin by electrostatic attraction upon drop coating. The platform i.e. the dendrimer-streptavidin modified electrode was electrochemically interrogated in phosphate buffer, ferrocyanide and H 2 O 2 . The dendrimer-streptavidin platform was used in the preparation of a simple DNA biosensor as a proof of concept. The supramolecular architecture of dendrimer-streptavidin was stable, electroactive and thus lends itself as a versatile immobilisation layer for any biotinylated bioreceptors in biosensor development. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. 3D Printing of Biocompatible Supramolecular Polymers and their Composites.

    Science.gov (United States)

    Hart, Lewis R; Li, Siwei; Sturgess, Craig; Wildman, Ricky; Jones, Julian R; Hayes, Wayne

    2016-02-10

    A series of polymers capable of self-assembling into infinite networks via supramolecular interactions have been designed, synthesized, and characterized for use in 3D printing applications. The biocompatible polymers and their composites with silica nanoparticles were successfully utilized to deposit both simple cubic structures, as well as a more complex twisted pyramidal feature. The polymers were found to be not toxic to a chondrogenic cell line, according to ISO 10993-5 and 10993-12 standard tests and the cells attached to the supramolecular polymers as demonstrated by confocal microscopy. Silica nanoparticles were then dispersed within the polymer matrix, yielding a composite material which was optimized for inkjet printing. The hybrid material showed promise in preliminary tests to facilitate the 3D deposition of a more complex structure.

  7. Supramolecular Derivation of Graphene Nanomaterials for Chemical Sensors

    DEFF Research Database (Denmark)

    Olsen, Gunnar

    With properties such as high surface area, high conductivity, and low production cost with easy up-scaling, graphene-like materials provide a promising support for many applications, one of which is for chemical sensors. By functionalization with molecular receptors such as supramolecular moieties...... of 10−5 M. In the second approach Azido-RGO was prepared as a general platform for post reduction modification. GO was here functionalized with a short linker terminated in an alcohol. The intermediate material was then reduced effectively with NaBH4, followed by chemical transformation of the alcohol...... atoms or slightly more than one azide per nm2 of RGO-sheet. This Azido-RGO was used in successful functionalization with the large supramolecular receptor molecules TTF-calix[4]pyrrole which function as a sensor for Cl− and potentially for TNB. The coverage achieved was one molecule per 50 – 60 carbon...

  8. Supramolecular Ferric Porphyrins as Cyanide Receptors in Aqueous Solution

    Science.gov (United States)

    2011-01-01

    All fundamental data about binding of the cyanide to a supramolecular complex composed of a per-O-methylated β-cyclodextrin dimer having an imidazole linker (Im3CD) and an anionic ferric porphyrin (Fe(III)TPPS) indicate that the Fe(III)TPPS/Im3CD complex is much better as an cyanide receptor in vivo than hydroxocobalamin, whose cyanide binding ability is lowered by its strong binding to serum proteins in the blood. PMID:24900285

  9. PEG-bis phosphonic acid based ionic supramolecular structures

    DEFF Research Database (Denmark)

    Gonzalez, Lidia; Skov, Anne Ladegaard; Hvilsted, Søren

    2014-01-01

    . The resulting ionic assemblies are very comprehensively characterized by ATR-FTIR, proton, and carbon-13 NMR spectroscopy that unequivocally demonstrate the ionic network formation through ammonium phophonates. The resulting salt and ionic networks are additionally analyzed by differential scanning calorimetry...... and thermogravimetric analysis. The conclusion is that mixing the virgin components at room temperature spontaneously form either a salt or ionic supramolecular networks. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim....

  10. Supramolecular Assembly of Complementary Cyanine Salt J-Aggregates

    KAUST Repository

    Li, Zhong’ an; Mukhopadhyay, Sukrit; Jang, Sei-Hum; Bredas, Jean-Luc; Jen, Alex K.-Y.

    2015-01-01

    An understanding of structure–property relationships in cyanine dyes is critical for their design and application. Anionic and cationic cyanines can be organized into complementary cyanine salts, offering potential building blocks to modulate their intra/intermolecular interactions in the solid state. Here, we demonstrate how the structures of these complementary salts can be tuned to achieve highly ordered J-type supramolecular aggregate structures of heptamethine dyes in crystalline solids.

  11. Supramolecular Assembly of Complementary Cyanine Salt J-Aggregates

    KAUST Repository

    Li, Zhong’an

    2015-09-09

    An understanding of structure–property relationships in cyanine dyes is critical for their design and application. Anionic and cationic cyanines can be organized into complementary cyanine salts, offering potential building blocks to modulate their intra/intermolecular interactions in the solid state. Here, we demonstrate how the structures of these complementary salts can be tuned to achieve highly ordered J-type supramolecular aggregate structures of heptamethine dyes in crystalline solids.

  12. Dielectric electroactive polymers comprising an ionic supramolecular structure

    DEFF Research Database (Denmark)

    2014-01-01

    The present invention relates to an ionic interpenetrating polymer network comprising at least one elastomer and an ionic supramolecular structure comprising the reaction product of at least two chemical compounds wherein each of said compounds has at least two functional groups and wherein said ...... compounds are able to undergo Lewis acid-base reactions. The interpenetrating polymer network may be used as dielectric electroactive polymers (DEAPs) having a high dielectric permittivity....

  13. Encoding complexity within supramolecular analogues of frustrated magnets

    Science.gov (United States)

    Cairns, Andrew B.; Cliffe, Matthew J.; Paddison, Joseph A. M.; Daisenberger, Dominik; Tucker, Matthew G.; Coudert, François-Xavier; Goodwin, Andrew L.

    2016-05-01

    The solid phases of gold(I) and/or silver(I) cyanides are supramolecular assemblies of inorganic polymer chains in which the key structural degrees of freedom—namely, the relative vertical shifts of neighbouring chains—are mathematically equivalent to the phase angles of rotating planar (‘XY’) spins. Here, we show how the supramolecular interactions between chains can be tuned to mimic different magnetic interactions. In this way, the structures of gold(I) and/or silver(I) cyanides reflect the phase behaviour of triangular XY magnets. Complex magnetic states predicted for this family of magnets—including collective spin-vortices of relevance to data storage applications—are realized in the structural chemistry of these cyanide polymers. Our results demonstrate how chemically simple inorganic materials can behave as structural analogues of otherwise inaccessible ‘toy’ spin models and also how the theoretical understanding of those models allows control over collective (‘emergent’) phenomena in supramolecular systems.

  14. Supramolecular photocatalyst of RGO-cyclodextrin-TiO2

    International Nuclear Information System (INIS)

    Shen, Jianfeng; Li, Na; Ye, Mingxin

    2013-01-01

    Graphical abstract: Supramolecular photocatalyst of RGO-cyclodextrin-TiO 2 was achieved, which showed high photocatalytic activity and adsorption capacity. Highlights: •Supramolecular photocatalyst of RGO-cyclodextrin-TiO 2 was achieved. •β-CD molecules acted as linkers between RGO and monodisperse TiO 2 nanoparticles. •Reduction of GO and preparation of RGO-cyclodextrin-TiO 2 was simultaneous. •The prepared RGO-cyclodextrin-TiO 2 shows high photocatalytic activity and adsorption capacity. -- Abstract: Reduced graphene oxide (RGO)/β-cyclodextrin (β-CD)/titanium oxide (TiO 2 ) supramolecular photocatalyst was synthesized with a one-pot hydrothermal method. The reducing process was accomplished with the attaching of β-CD and generation of TiO 2 . β-CD acted as a linker between RGO and monodisperse TiO 2 nanoparticles. The structure and composition of the hybrid had been characterized by Fourier transform infrared spectroscopy, Raman spectroscopy, thermal gravimetric analysis, X-ray diffraction and Transmission electron microscopy. The as-prepared RGO-CD-TiO 2 showed significant enhanced performance for phenol and Cr (VI) removal, due to the effective transfer of photo-generated electron from TiO2 to RGO and improved absorbance performance of the hybrid

  15. The use of supramolecular chemistry in dye delivery systems

    International Nuclear Information System (INIS)

    Merckel, Daniel Andrew Sturton

    2002-01-01

    This thesis reports an investigation into supramolecular recognition of the sulfate/ sulfonate oxoanionic group, a moiety present in the majority of reactive dyes. In the first section the problems associated with the use of reactive dyes in dyeing cotton fabrics together with a literature review of supramolecular approaches to anion recognition are discussed. Drawing on the current literature concerning anion recognition (in particular the recognition of phosphates), the main body of the thesis concerns the design and synthesis of several series ofC-shaped (tweezer) and tripodal potential sulfate/ sulfonate receptors. These receptors incorporate the H-bond donor groups guanidine and thiourea and to a lesser extent urea and amide functionalities. In addition the behaviour of potential tweezer-like receptor molecules based on s-triazine (derived from cyanuric chloride) has also been investigated. The sulfate/ sulfonate and related phosphonate association properties of these potential receptors have been studied. Particular emphasis has been placed on the solid-state supramolecular structures formed by these complexes as determined by single crystal X-ray structural studies, and several novel and revealing examples have been analysed in detail. NMR titration binding studies have also been undertaken in order to investigate the complexation behaviour of several receptors with ''model dye'' phosphonates and sulfonates in solution. In addition a number of single crystal X-ray crystallographic studies were undertaken for other members of the Grossel research group during the course of this work, and the results of these structural studies are also reported. (author)

  16. Glucosamine-Based Supramolecular Nanotubes for Human Mesenchymal Cell Therapy.

    Science.gov (United States)

    Talloj, Satish Kumar; Cheng, Bill; Weng, Jen-Po; Lin, Hsin-Chieh

    2018-04-23

    Herein, we demonstrate an example of glucosamine-based supramolecular hydrogels that can be used for human mesenchymal cell therapy. We designed and synthesized a series of amino acid derivatives based on a strategy of capping d-glucosamine moiety at the C-terminus and fluorinated benzyl group at the N-terminus. From a systematic study on chemical structures, we discovered that the glucosamine-based supramolecular hydrogel [pentafluorobenzyl (PFB)-F-Glu] self-assembled with one-dimensional nanotubular structures at physiological pH. The self-assembly of a newly discovered PFB-F-Glu motif is attributed to the synergistic effect of π-π stacking and extensive intermolecular hydrogen bonding network in aqueous medium. Notably, PFB-F-Glu nanotubes are proven to be nontoxic to human mesenchymal stem cells (hMSCs) and have been shown to enhance hMSC proliferation while maintaining their pluripotency. Retaining of pluripotency capabilities provides potentially unlimited source of undifferentiated cells for the treatment of future cell therapies. Furthermore, hMSCs cultured on PFB-F-Glu are able to secrete paracrine factors that downregulate profibrotic gene expression in lipopolysaccharide-treated human skin fibroblasts, which demonstrates that PFB-F-Glu nanotubes have the potential to be used for wound healing applications. Overall, this article addresses the importance of chemical design to generate supramolecular biomaterials for stem cell therapy.

  17. From supramolecular electrochemistry to molecular-level devices

    Energy Technology Data Exchange (ETDEWEB)

    Credi, Alberto; Ferrer Ribera, Belen; Venturi, Margherita

    2004-09-15

    Supramolecular (multi-component) systems can perform complex functions which result from the cooperation of actions performed by suitably selected molecular components. Looking at supramolecular systems, from the viewpoint of the functions, shows that the concept of macroscopic device can be extended to molecular level. Nature exploits very complex molecular-level devices to substain life, and, in the last twenty years, the development of supramolecular chemistry has allowed the construction of simple molecular-level devices, that are of interest not only for basic research, but also for the growth of nanoscience and nanotechnology. Molecular-level devices operate via electronic and/or nuclear rearrangements, and like macroscopic devices, they need energy to operate and signals to communicate with the operator. Electrochemistry can provide the answer to this dual requirement, since electrons/holes, besides supplying the energy needed to make a devices work, can also be useful to 'read' the state of the system and thus to control and monitor the operation of the device. In this article, some examples of molecular-level devices investigated in our laboratory will be reviewed.

  18. A new configurational bias scheme for sampling supramolecular structures

    Energy Technology Data Exchange (ETDEWEB)

    De Gernier, Robin; Mognetti, Bortolo M., E-mail: bmognett@ulb.ac.be [Center for Nonlinear Phenomena and Complex Systems, Université Libre de Bruxelles, Code Postal 231, Campus Plaine, B-1050 Brussels (Belgium); Curk, Tine [Department of Chemistry, University of Cambridge, Cambridge CB2 1EW (United Kingdom); Dubacheva, Galina V. [Biosurfaces Unit, CIC biomaGUNE, Paseo Miramon 182, 20009 Donostia - San Sebastian (Spain); Richter, Ralf P. [Biosurfaces Unit, CIC biomaGUNE, Paseo Miramon 182, 20009 Donostia - San Sebastian (Spain); Université Grenoble Alpes, DCM, 38000 Grenoble (France); CNRS, DCM, 38000 Grenoble (France); Max Planck Institute for Intelligent Systems, 70569 Stuttgart (Germany)

    2014-12-28

    We present a new simulation scheme which allows an efficient sampling of reconfigurable supramolecular structures made of polymeric constructs functionalized by reactive binding sites. The algorithm is based on the configurational bias scheme of Siepmann and Frenkel and is powered by the possibility of changing the topology of the supramolecular network by a non-local Monte Carlo algorithm. Such a plan is accomplished by a multi-scale modelling that merges coarse-grained simulations, describing the typical polymer conformations, with experimental results accounting for free energy terms involved in the reactions of the active sites. We test the new algorithm for a system of DNA coated colloids for which we compute the hybridisation free energy cost associated to the binding of tethered single stranded DNAs terminated by short sequences of complementary nucleotides. In order to demonstrate the versatility of our method, we also consider polymers functionalized by receptors that bind a surface decorated by ligands. In particular, we compute the density of states of adsorbed polymers as a function of the number of ligand–receptor complexes formed. Such a quantity can be used to study the conformational properties of adsorbed polymers useful when engineering adsorption with tailored properties. We successfully compare the results with the predictions of a mean field theory. We believe that the proposed method will be a useful tool to investigate supramolecular structures resulting from direct interactions between functionalized polymers for which efficient numerical methodologies of investigation are still lacking.

  19. Consequences of chirality on the dynamics of a water-soluble supramolecular polymer

    NARCIS (Netherlands)

    Baker, M.B.; Albertazzi, L.; Voets, Ilja K.; Leenders, C.M.A.; Palmans, A.R.A.; Pavan, G.M.; Meijer, E. W.

    2015-01-01

    The rational design of supramolecular polymers in water is imperative for their widespread use, but the design principles for these systems are not well understood. Herein, we employ a multi-scale (spatial and temporal) approach to differentiate two analogous water-soluble supramolecular polymers:

  20. Dynamic and bio-orthogonal protein assembly along a supramolecular polymer

    NARCIS (Netherlands)

    Petkau - Milroy, K.; Uhlenheuer, D.A.; Spiering, A.J.H.; Vekemans, J.A.J.M.; Brunsveld, L.

    2013-01-01

    Dynamic protein assembly along supramolecular columnar polymers has been achieved through the site-specific covalent attachment of different SNAP-tag fusion proteins to self-assembled benzylguanine-decorated discotics. The self-assembly of monovalent discotics into supramolecular polymers creates a

  1. The role of supramolecular chemistry in stimuli responsive and hierarchically structured functional organic materials

    NARCIS (Netherlands)

    Schenning, A.P.H.J.; Bastiaansen, C.W.M.; Broer, D.J.; Debije, M.G.

    2014-01-01

    ABSTRACT: In this review, we show the important role of supramolecular chemistry in the fabrication of stimuli responsive and hierarchically structured liquid crystalline polymer networks. Supramolecular interactions can be used to create three dimensional order or as molecular triggers in materials

  2. Consequences of chirality on the dynamics of a water-soluble supramolecular polymer.

    Science.gov (United States)

    Baker, Matthew B; Albertazzi, Lorenzo; Voets, Ilja K; Leenders, Christianus M A; Palmans, Anja R A; Pavan, Giovanni M; Meijer, E W

    2015-02-20

    The rational design of supramolecular polymers in water is imperative for their widespread use, but the design principles for these systems are not well understood. Herein, we employ a multi-scale (spatial and temporal) approach to differentiate two analogous water-soluble supramolecular polymers: one with and one without a stereogenic methyl. Initially aiming simply to understand the molecular behaviour of these systems in water, we find that while the fibres may look identical, the introduction of homochirality imparts a higher level of internal order to the supramolecular polymer. Although this increased order does not seem to affect the basic dimensions of the supramolecular fibres, the equilibrium dynamics of the polymers differ by almost an order of magnitude. This report represents the first observation of a structure/property relationship with regard to equilibrium dynamics in water-soluble supramolecular polymers.

  3. Consequences of chirality on the dynamics of a water-soluble supramolecular polymer

    Science.gov (United States)

    Baker, Matthew B.; Albertazzi, Lorenzo; Voets, Ilja K.; Leenders, Christianus M. A.; Palmans, Anja R. A.; Pavan, Giovanni M.; Meijer, E. W.

    2015-02-01

    The rational design of supramolecular polymers in water is imperative for their widespread use, but the design principles for these systems are not well understood. Herein, we employ a multi-scale (spatial and temporal) approach to differentiate two analogous water-soluble supramolecular polymers: one with and one without a stereogenic methyl. Initially aiming simply to understand the molecular behaviour of these systems in water, we find that while the fibres may look identical, the introduction of homochirality imparts a higher level of internal order to the supramolecular polymer. Although this increased order does not seem to affect the basic dimensions of the supramolecular fibres, the equilibrium dynamics of the polymers differ by almost an order of magnitude. This report represents the first observation of a structure/property relationship with regard to equilibrium dynamics in water-soluble supramolecular polymers.

  4. Self-Assembly of Supramolecular Aggregates Based on Sector- and Cone-Shaped Dendrons and Bolaamphiphiles

    Science.gov (United States)

    Shcherbina, M. A.; Chvalun, S. N.

    2018-06-01

    Using a number of classes of such sector-shaped macromolecules as derivatives of 2,3,4- and 3,4,5- tri(dodecyloxy)benzenesulfonic acid and dendrimers based on gallic acid as an example, the main stages in the formation of supramolecular ensembles are considered: the formation of individual supramolecular aggregates due to the weak noncovalent interactions of mesogenic groups, and the subsequent ordering within these aggregates, which lowers the free energy of a system. Supramolecular aggregates are in turn organized into two- or three-dimensional supramolecular lattices. It is shown that the shape of the supramolecular aggregates and its change along with temperature are functions of the chemical structure of the mesogenic group (resulting in the controlled design of complex self-organizing systems with a given response to external stimuli).

  5. Dielectric properties of supramolecular ionic structures obtained from multifunctional carboxylic acids and amines

    DEFF Research Database (Denmark)

    Gonzalez, Lidia; Yu, Liyun; Hvilsted, Søren

    2014-01-01

    The dielectric properties of several supramolecular ionic polymers and networks, linked by the ammonium salts of hexamethylene diamine (HMDA), tris(2-aminoethyl)amine (TAEA), poly(propylene imine) (PPI) dendrimers and two short bis carboxymethyl ether-terminated poly(ethylene glycol)s (Di......COOH-PEG), are reported in this paper. All supramolecular ionic polymers and networks exhibit very high relative dielectric permittivities ( 3 0 )( 10 2 – 10 6 ) at low frequencies, and signi fi cantly lower values (from 1 up to 26) at high frequencies. Additionally, the dielectric properties of supramolecular ionic......), are investigated. Here the relative dielectric permittivities of the supramolecular ionic structures formed with the multifunctional carboxylic acids were lower than those from the supramolecular ionic structures formed with the two carboxymethyl ether-terminated poly(ethylene glycol)s....

  6. Self-assembly of heterogeneous supramolecular structures with uniaxial anisotropy.

    Science.gov (United States)

    Ruiz-Osés, M; Gonzalez-Lakunza, N; Silanes, I; Gourdon, A; Arnau, A; Ortega, J E

    2006-12-28

    Uniaxial anisotropy in two-dimensional self-assembled supramolecular structures is achieved by the coadsorption of two different linear molecules with complementary amine and imide functionalization. The two-dimensional monolayer is defined by a one-dimensional stack of binary chains, which can be forced to line up along steps in vicinal surfaces. The competing driving forces in the self-organization process are discussed in light of the structures observed during single molecule adsorption and coadsorption on flat and vicinal surfaces and the corresponding theoretical calculations.

  7. Supramolecular nanofibers of triamcinolone acetonide for uveitis therapy

    Science.gov (United States)

    Li, Xingyi; Wang, Yuqin; Yang, Chengbiao; Shi, Shuai; Jin, Ling; Luo, Zichao; Yu, Jing; Zhang, Zhaoliang; Yang, Zhimou; Chen, Hao

    2014-11-01

    Supramolecular nanofibers of prodrugs hold advantages for drug release due to their high drug payload, sustained and constant drug release behavior, and stimuli responsiveness. In this study, we report on a supramolecular hydrogel mainly formed by a clinically used drug triamcinolone acetonide (TA). Such a hydrogel could only be prepared via an ester bond hydrolysis process from its prodrug of succinated triamcinolone acetonide (STA). The resulting hydrogel could constantly release TA in the in vitro release experiment. The TA hydrogel possessed an excellent transscleral penetration ability, as evaluated by the in vitro transscleral transport study. The developed TA hydrogel also exhibited a great ocular compatibility in rats, as indicated by the optical coherence tomography (OCT) images, HE observation, and glial fibrillary acidic protein (GFAP) and vimentin immuno-staining assays of the retinas. Our TA hydrogel showed a decreased efficacy to inhibit ocular inflammation in the rat's experiment autoimmune uveitis (EAU) model compared to the commercial TA suspension (Transton®), but without causing complications such as high intraocular pressure and cataracts. These promising properties of the hydrogel indicated its great potential for the treatment of eye diseases.Supramolecular nanofibers of prodrugs hold advantages for drug release due to their high drug payload, sustained and constant drug release behavior, and stimuli responsiveness. In this study, we report on a supramolecular hydrogel mainly formed by a clinically used drug triamcinolone acetonide (TA). Such a hydrogel could only be prepared via an ester bond hydrolysis process from its prodrug of succinated triamcinolone acetonide (STA). The resulting hydrogel could constantly release TA in the in vitro release experiment. The TA hydrogel possessed an excellent transscleral penetration ability, as evaluated by the in vitro transscleral transport study. The developed TA hydrogel also exhibited a great ocular

  8. Supramolecular curcumin-barium prodrugs for formulating with ceramic particles.

    Science.gov (United States)

    Kamalasanan, Kaladhar; Anupriya; Deepa, M K; Sharma, Chandra P

    2014-10-01

    A simple and stable curcumin-ceramic combined formulation was developed with an aim to improve curcumin stability and release profile in the presence of reactive ceramic particles for potential dental and orthopedic applications. For that, curcumin was complexed with barium (Ba(2+)) to prepare curcumin-barium (BaCur) complex. Upon removal of the unbound curcumin and Ba(2+) by dialysis, a water-soluble BaCur complex was obtained. The complex was showing [M+1](+) peak at 10,000-20,000 with multiple fractionation peaks of MALDI-TOF-MS studies, showed that the complex was a supramolecular multimer. The (1)H NMR and FTIR studies revealed that, divalent Ba(2+) interacted predominantly through di-phenolic groups of curcumin to form an end-to-end complex resulted in supramolecular multimer. The overall crystallinity of the BaCur was lower than curcumin as per XRD analysis. The complexation of Ba(2+) to curcumin did not degrade curcumin as per HPLC studies. The fluorescence spectrum was blue shifted upon Ba(2+) complexation with curcumin. Monodisperse nanoparticles with size less than 200dnm was formed, out of the supramolecular complex upon dialysis, as per DLS, and upon loading into pluronic micelles the size was remaining in similar order of magnitude as per DLS and AFM studies. Stability of the curcumin was improved greater than 50% after complexation with Ba(2+) as per UV/Vis spectroscopy. Loading of the supramloecular nanoparticles into pluronic micelles had further improved the stability of curcumin to approx. 70% in water. These BaCur supramolecule nanoparticles can be considered as a new class of prodrugs with improved solubility and stability. Subsequently, ceramic nanoparticles with varying chemical composition were prepared for changing the material surface reactivity in terms of the increase in, degradability, surface pH and protein adsorption. Further, these ceramic particles were combined with curcumin prodrug formulations and optimized the curcumin release

  9. Predicting supramolecular self-assembly on reconstructed metal surfaces

    Science.gov (United States)

    Roussel, Thomas J.; Barrena, Esther; Ocal, Carmen; Faraudo, Jordi

    2014-06-01

    The prediction of supramolecular self-assembly onto solid surfaces is still challenging in many situations of interest for nanoscience. In particular, no previous simulation approach has been capable to simulate large self-assembly patterns of organic molecules over reconstructed surfaces (which have periodicities over large distances) due to the large number of surface atoms and adsorbing molecules involved. Using a novel simulation technique, we report here large scale simulations of the self-assembly patterns of an organic molecule (DIP) over different reconstructions of the Au(111) surface. We show that on particular reconstructions, the molecule-molecule interactions are enhanced in a way that long-range order is promoted. Also, the presence of a distortion in a reconstructed surface pattern not only induces the presence of long-range order but also is able to drive the organization of DIP into two coexisting homochiral domains, in quantitative agreement with STM experiments. On the other hand, only short range order is obtained in other reconstructions of the Au(111) surface. The simulation strategy opens interesting perspectives to tune the supramolecular structure by simulation design and surface engineering if choosing the right molecular building blocks and stabilising the chosen reconstruction pattern.The prediction of supramolecular self-assembly onto solid surfaces is still challenging in many situations of interest for nanoscience. In particular, no previous simulation approach has been capable to simulate large self-assembly patterns of organic molecules over reconstructed surfaces (which have periodicities over large distances) due to the large number of surface atoms and adsorbing molecules involved. Using a novel simulation technique, we report here large scale simulations of the self-assembly patterns of an organic molecule (DIP) over different reconstructions of the Au(111) surface. We show that on particular reconstructions, the molecule

  10. Self-Assembled Supramolecular Architectures Lyotropic Liquid Crystals

    CERN Document Server

    Garti, Nissim

    2012-01-01

    This book will describe fundamentals and recent developments in the area of Self-Assembled Supramolecular Architecture and their relevance to the  understanding of the functionality of  membranes  as delivery systems for active ingredients. As the heirarchial architectures determine their performance capabilities, attention will be paid to theoretical and design aspects related to the construction of lyotropic liquid crystals: mesophases such as lamellar, hexagonal, cubic, sponge phase micellosomes. The book will bring to the reader mechanistic aspects, compositional c

  11. Fluorescent supramolecular micelles for imaging-guided cancer therapy

    Science.gov (United States)

    Sun, Mengmeng; Yin, Wenyan; Dong, Xinghua; Yang, Wantai; Zhao, Yuliang; Yin, Meizhen

    2016-02-01

    A novel smart fluorescent drug delivery system composed of a perylene diimide (PDI) core and block copolymer poly(d,l-lactide)-b-poly(ethyl ethylene phosphate) is developed and named as PDI-star-(PLA-b-PEEP)8. The biodegradable PDI-star-(PLA-b-PEEP)8 is a unimolecular micelle and can self-assemble into supramolecular micelles, called as fluorescent supramolecular micelles (FSMs), in aqueous media. An insoluble drug camptothecin (CPT) can be effectively loaded into the FSMs and exhibits pH-responsive release. Moreover, the FSMs with good biocompatibility can also be employed as a remarkable fluorescent probe for cell labelling because the maximum emission of PDI is beneficial for bio-imaging. The flow cytometry and confocal laser scanning microscopy analysis demonstrate that the micelles are easily endocytosed by cancer cells. In vitro and in vivo tumor growth-inhibitory studies reveal a better therapeutic effect of FSMs after CPT encapsulation when compared with the free CPT drug. The multifunctional FSM nanomedicine platform as a nanovehicle has great potential for fluorescence imaging-guided cancer therapy.A novel smart fluorescent drug delivery system composed of a perylene diimide (PDI) core and block copolymer poly(d,l-lactide)-b-poly(ethyl ethylene phosphate) is developed and named as PDI-star-(PLA-b-PEEP)8. The biodegradable PDI-star-(PLA-b-PEEP)8 is a unimolecular micelle and can self-assemble into supramolecular micelles, called as fluorescent supramolecular micelles (FSMs), in aqueous media. An insoluble drug camptothecin (CPT) can be effectively loaded into the FSMs and exhibits pH-responsive release. Moreover, the FSMs with good biocompatibility can also be employed as a remarkable fluorescent probe for cell labelling because the maximum emission of PDI is beneficial for bio-imaging. The flow cytometry and confocal laser scanning microscopy analysis demonstrate that the micelles are easily endocytosed by cancer cells. In vitro and in vivo tumor growth

  12. Supramolecular chemistry-general principles and selected examples from anion recognition and metallosupramolecular chemistry.

    Science.gov (United States)

    Albrecht, Markus

    2007-12-01

    This review gives an introduction into supramolecular chemistry describing in the first part general principles, focusing on terms like noncovalent interaction, molecular recognition, self-assembly, and supramolecular function. In the second part those will be illustrated by simple examples from our laboratories. Supramolecular chemistry is the science that bridges the gap between the world of molecules and nanotechnology. In supramolecular chemistry noncovalent interactions occur between molecular building blocks, which by molecular recognition and self-assembly form (functional) supramolecular entities. It is also termed the "chemistry of the noncovalent bond." Molecular recognition is based on geometrical complementarity based on the "key-and-lock" principle with nonshape-dependent effects, e.g., solvatization, being also highly influential. Self-assembly leads to the formation of well-defined aggregates. Hereby the overall structure of the target ensemble is controlled by the symmetry features of the certain building blocks. Finally, the aggregates can possess special properties or supramolecular functions, which are only found in the ensemble but not in the participating molecules. This review gives an introduction on supramolecular chemistry and illustrates the fundamental principles by recent examples from our group.

  13. Supramolecular Cocrystals of Gliclazide: Synthesis, Characterization and Evaluation.

    Science.gov (United States)

    Chadha, Renu; Rani, Dimpy; Goyal, Parnika

    2017-03-01

    To prepare the supramolecular cocrystals of gliclazide (GL, a BCS class II drug molecule) via mechanochemical route, with the goal of improving physicochemical and biopharmaceutical properties. Two cocrystals of GL with GRAS status coformers, sebacic acid (GL-SB; 1:1) and α-hydroxyacetic acid (GL-HA; 1:1) were screened out using liquid assisted grinding. The prepared cocrystals were characterized using thermal and analytical techniques followed by evaluation of antidiabetic activity and pharmacokinetic parameters. The generation of new, single and pure crystal forms was characterized by DSC and PXRD. The crystal structure determination from PXRD revealed the existence of both cocrystals in triclinic (P-1) crystal system. The hydrogen bonded network, determined by material studio was well supported by shifts in FTIR and SSNMR. Both the new solid forms displayed improved solubility, IDR, antidiabetic activity and pharmacokinetic parameters as compared to GL. The improvement in these physicochemical and biopharmaceutical properties corroborated the fact that the supramolecular cocrystallization may be useful in the development of pharmaceutical crystalline materials with interesting network and properties.

  14. Coherent states field theory in supramolecular polymer physics

    Science.gov (United States)

    Fredrickson, Glenn H.; Delaney, Kris T.

    2018-05-01

    In 1970, Edwards and Freed presented an elegant representation of interacting branched polymers that resembles the coherent states (CS) formulation of second-quantized field theory. This CS polymer field theory has been largely overlooked during the intervening period in favor of more conventional "auxiliary field" (AF) interacting polymer representations that form the basis of modern self-consistent field theory (SCFT) and field-theoretic simulation approaches. Here we argue that the CS representation provides a simpler and computationally more efficient framework than the AF approach for broad classes of reversibly bonding polymers encountered in supramolecular polymer science. The CS formalism is reviewed, initially for a simple homopolymer solution, and then extended to supramolecular polymers capable of forming reversible linkages and networks. In the context of the Edwards model of a non-reacting homopolymer solution and one and two-component models of telechelic reacting polymers, we discuss the structure of CS mean-field theory, including the equivalence to SCFT, and show how weak-amplitude expansions (random phase approximations) can be readily developed without explicit enumeration of all reaction products in a mixture. We further illustrate how to analyze CS field theories beyond SCFT at the level of Gaussian field fluctuations and provide a perspective on direct numerical simulations using a recently developed complex Langevin technique.

  15. Supramolecular nano-sniffers for ultrasensitive detection of formaldehyde.

    Science.gov (United States)

    Akshath, Uchangi Satyaprasad; Bhatt, Praveena

    2018-02-15

    Supramolecular nanoparticle hybrids for biosensing of analytes have been a major focus due to their tunable optical and surface properties. Quantum dots-Gold nanoparticle (QDs-GNP) based FRET probes involving turn on/off principles have gained immense interest due to their specificity and sensitivity. Recent focus is on applying these supramolecular hybrids for enzyme operated biosensors that can specifically turn-on fluorescence induced by co-factor or product formed from enzymatic reaction. The present study focuses on locking and unlocking the interaction between QD-GNP pair leading to differential fluorescent properties. Cationic GNPs efficiently quenched the anionic QD fluorescence by forming nanoparticle hybrid. Quenching interaction between QD-GNP pair was unlocked by NADH leading to QD fluorescence turn-on. This phenomenon was applied for the successful detection of formaldehyde using NAD + dependent formaldehyde dehydrogenase. The proposed nano-sniffer could successfully detect formaldehyde from 0.001 to 100000ng/mL (R 2 = 0.9339) by the turn off-turn on principle. It could also detect formaldehyde in fruit juice and wine samples indicating its stability and sensitivity in real samples. The proposed nanoprobe can have wide applications in developing enzyme biosensors in future. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Enhancing SERS by Means of Supramolecular Charge Transfer

    Science.gov (United States)

    Wong, Eric; Flood, Amar; Morales, Alfredo

    2009-01-01

    In a proposed method of sensing small quantities of molecules of interest, surface enhanced Raman scattering (SERS) spectroscopy would be further enhanced by means of intermolecular or supramolecular charge transfer. There is a very large potential market for sensors based on this method for rapid detection of chemical and biological hazards. In SERS, the Raman signals (vibrational spectra) of target molecules become enhanced by factors of the order of 108 when those molecules are in the vicinities of nanostructured substrate surfaces that have been engineered to have plasmon resonances that enhance local electric fields. SERS, as reported in several prior NASA Tech Briefs articles and elsewhere, has remained a research tool and has not yet been developed into a practical technique for sensing of target molecules: this is because the short range (5 to 20 nm) of the field enhancement necessitates engineering of receptor molecules to attract target molecules to the nanostructured substrate surfaces and to enable reliable identification of the target molecules in the presence of interferants. Intermolecular charge-transfer complexes have been used in fluorescence-, photoluminescence-, and electrochemistry-based techniques for sensing target molecules, but, until now, have not been considered for use in SERS-based sensing. The basic idea of the proposed method is to engineer receptor molecules that would be attached to nanostructured SERS substrates and that would interact with the target molecules to form receptor-target supramolecular charge-transfer complexes wherein the charge transfer could be photoexcited.

  17. Proteins evolve on the edge of supramolecular self-assembly

    Science.gov (United States)

    Garcia-Seisdedos, Hector; Empereur-Mot, Charly; Elad, Nadav; Levy, Emmanuel D.

    2017-08-01

    The self-association of proteins into symmetric complexes is ubiquitous in all kingdoms of life. Symmetric complexes possess unique geometric and functional properties, but their internal symmetry can pose a risk. In sickle-cell disease, the symmetry of haemoglobin exacerbates the effect of a mutation, triggering assembly into harmful fibrils. Here we examine the universality of this mechanism and its relation to protein structure geometry. We introduced point mutations solely designed to increase surface hydrophobicity among 12 distinct symmetric complexes from Escherichia coli. Notably, all responded by forming supramolecular assemblies in vitro, as well as in vivo upon heterologous expression in Saccharomyces cerevisiae. Remarkably, in four cases, micrometre-long fibrils formed in vivo in response to a single point mutation. Biophysical measurements and electron microscopy revealed that mutants self-assembled in their folded states and so were not amyloid-like. Structural examination of 73 mutants identified supramolecular assembly hot spots predictable by geometry. A subsequent structural analysis of 7,471 symmetric complexes showed that geometric hot spots were buffered chemically by hydrophilic residues, suggesting a mechanism preventing mis-assembly of these regions. Thus, point mutations can frequently trigger folded proteins to self-assemble into higher-order structures. This potential is counterbalanced by negative selection and can be exploited to design nanomaterials in living cells.

  18. Supramolecular core-shell nanoparticles for photoconductive device applications

    Science.gov (United States)

    Cheng, Chih-Chia; Chen, Jem-Kun; Shieh, Yeong-Tarng; Lee, Duu-Jong

    2016-08-01

    We report a breakthrough discovery involving supramolecular-based strategies to construct novel core-shell heterojunction nanoparticles with hydrophilic adenine-functionalized polythiophene (PAT) as the core and hydrophobic phenyl-C61-butyric acid methyl ester (PCBM) as the shell, which enables the conception of new functional supramolecular assemblies for constructing functional nanomaterials for applications in optoelectronic devices. The generated nanoparticles exhibit uniform spherical shape, well-controlled tuning of particle size with narrow size distributions, and excellent electrochemical stability in solution and the solid state owing to highly efficient energy transfer from PAT to PCBM. When the PAT/PCBM nanoparticles were fabricated into a photoconducting layer in an electronic device, the resulting device showed excellent electric conduction characteristics, including an electrically-tunable voltage-controlled switch, and high short-circuit current and open-circuit voltage. These observations demonstrate how the self-assembly of PAT/PCBM into specific nanostructures may help to promote efficient charge generation and transport processes, suggesting potential for a wide variety of applications as a promising candidate material for bulk heterojunction polymer devices.

  19. A Supramolecular Approach toward Bioinspired PAMAM-Dendronized Fusion Toxins.

    Science.gov (United States)

    Kuan, Seah Ling; Förtsch, Christina; Ng, David Yuen Wah; Fischer, Stephan; Tokura, Yu; Liu, Weina; Wu, Yuzhou; Koynov, Kaloian; Barth, Holger; Weil, Tanja

    2016-06-01

    Nature has provided a highly optimized toolbox in bacterial endotoxins with precise functions dictated by their clear structural division. Inspired by this streamlined design, a supramolecular approach capitalizing on the strong biomolecular (streptavidin (SA))-biotin interactions is reported herein to prepare two multipartite fusion constructs, which involves the generation 2.0 (D2) or generation 3.0 (D3) polyamidoamine-dendronized transporter proteins (dendronized streptavidin (D3SA) and dendronized human serum albumin (D2HSA)) non-covalently fused to the C3bot1 enzyme from Clostridium botulinum, a potent and specific Rho-inhibitor. The fusion constructs, D3SA-C3 and D2HSA-C3, represent the first examples of dendronized protein transporters that are fused to the C3 enzyme, and it is successfully demonstrated that the C3 Rho-inhibitor is delivered into the cytosol of mammalian cells as determined from the characteristic C3-mediated changes in cell morphology and confocal microscopy. The design circumvents the low uptake of the C3 enzyme by eukaryotic cells and holds great promise for reprogramming the properties of toxin enzymes using a supramolecular approach to broaden their therapeutic applications. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Supramolecular Drug Delivery Systems Based on Water-Soluble Pillar[n]arenes.

    Science.gov (United States)

    Wu, Xuan; Gao, Lei; Hu, Xiao-Yu; Wang, Leyong

    2016-06-01

    Supramolecular drug delivery systems (SDDSs), including various kinds of nanostructures that are assembled by reversible noncovalent interactions, have attracted considerable attention as ideal drug carriers owing to their fascinating ability to undergo dynamic switching of structure, morphology, and function in response to various external stimuli, which provides a flexible and robust platform for designing and developing functional and smart supramolecular nano-drug carriers. Pillar[n]arenes represent a new generation of macrocyclic hosts, which have unique structures and excellent properties in host-guest chemistry. This account describes recent progress in our group to develop pillararene-based stimuli-responsive supramolecular nanostructures constructed by reversible host-guest interactions for controllable anticancer drug delivery. The potential applications of these supramolecular drug carriers in cancer treatment and the fundamental questions facing SDDSs are also discussed. © 2016 The Chemical Society of Japan & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Insight into the chiral induction in supramolecular stacks through preferential chiral salvation

    NARCIS (Netherlands)

    George, S.J.; Tomovic, Z.; Schenning, A.P.H.J.; Meijer, E.W.

    2011-01-01

    Preferred handedness in the supramolecular chirality of self-assembled achiral oligo(p-phenylenevinylene) (OPV) derivatives is induced by chiral solvents and spectroscopic probing provides insight into the mechanistic aspects of this chiral induction through chiral solvation

  2. Solid structures of the stepwise self-assembled copillar[5]arene-based supramolecular polymers

    Energy Technology Data Exchange (ETDEWEB)

    Park, Yeon Sil; Hwang, Seong Min; Shin, Jae Yeon; Paek, Kyung Soo [Dept. of Chemistry, Soongsil University, Seoul (Korea, Republic of)

    2016-10-15

    Development of supramolecular polymer has attracted much interest because of their interesting properties such as stimuli-responsiveness, recycling, self-healing and degradability, and their consequential applications. The essential feature of this class of polymers is the self-assembly of discrete monomeric subunits via non-covalent interactions or dynamic covalent bonds. Among the many monomeric subunits, pillar[n]arenes have been ideal building blocks for the fabrication of polymeric supramolecules because of their intrinsic characteristics. The ring-shaped morphologies in supramolecular polymer P are probably due to the tendency of the end-to-end connection in the solid state of long flexible supramolecular chains. The size increase of nano-rings as the stepwise addition increases might be due to the fact that the linear supramolecular polymer P in solution seems to be maintained until the nano-ring formation by solidification.

  3. From metal-organic squares to porous zeolite-like supramolecular assemblies

    KAUST Repository

    Wang, Shuang; Zhao, Tingting; Li, Guanghua; Wojtas, Łukasz; Huo, Qisheng; Eddaoudi, Mohamed; Liu, Yunling

    2010-01-01

    We report the synthesis, structure, and characterization of two novel porous zeolite-like supramolecular assemblies, ZSA-1 and ZSA-2, having zeolite gis and rho topologies, respectively. The two compounds were assembled from functional metal

  4. Star-shaped tetrathiafulvalene oligomers towards the construction of conducting supramolecular assembly.

    Science.gov (United States)

    Iyoda, Masahiko; Hasegawa, Masashi

    2015-01-01

    The construction of redox-active supramolecular assemblies based on star-shaped and radially expanded tetrathiafulvalene (TTF) oligomers with divergent and extended conjugation is summarized. Star-shaped TTF oligomers easily self-aggregate with a nanophase separation to produce supramolecular structures, and their TTF units stack face-to-face to form columnar structures using the fastener effect. Based on redox-active self-organizing supramolecular structures, conducting nanoobjects are constructed by doping of TTF oligomers with oxidants after the formation of such nanostructures. Although radical cations derived from TTF oligomers strongly interact in solution to produce a mixed-valence dimer and π-dimer, it seems to be difficult to produce nanoobjects of radical cations different from those of neutral TTF oligomers. In some cases, however, radical cations form nanostructured fibers and rods by controlling the supramolecular assembly, oxidation states, and counter anions employed.

  5. Solid structures of the stepwise self-assembled copillar[5]arene-based supramolecular polymers

    International Nuclear Information System (INIS)

    Park, Yeon Sil; Hwang, Seong Min; Shin, Jae Yeon; Paek, Kyung Soo

    2016-01-01

    Development of supramolecular polymer has attracted much interest because of their interesting properties such as stimuli-responsiveness, recycling, self-healing and degradability, and their consequential applications. The essential feature of this class of polymers is the self-assembly of discrete monomeric subunits via non-covalent interactions or dynamic covalent bonds. Among the many monomeric subunits, pillar[n]arenes have been ideal building blocks for the fabrication of polymeric supramolecules because of their intrinsic characteristics. The ring-shaped morphologies in supramolecular polymer P are probably due to the tendency of the end-to-end connection in the solid state of long flexible supramolecular chains. The size increase of nano-rings as the stepwise addition increases might be due to the fact that the linear supramolecular polymer P in solution seems to be maintained until the nano-ring formation by solidification

  6. Molecular printboards as a general platform for protein immobilization: A supramolecular solution to nonspecific adsorption

    NARCIS (Netherlands)

    Ludden, M.J.W.; Mulder, A.; Tampe, Robert; Reinhoudt, David; Huskens, Jurriaan

    2007-01-01

    Be specific: A supramolecular adsorbate consisting of an adamantyl group (red) and an oligo(ethylene glycol) chain has been designed to prevent nonspecific protein adsorption at cyclodextrin molecular printboards. The adamantyl group allows specific and reversible interactions. Specific

  7. Self-Healing Supramolecular Hydrogels Based on Reversible Physical Interactions

    Directory of Open Access Journals (Sweden)

    Satu Strandman

    2016-04-01

    Full Text Available Dynamic and reversible polymer networks capable of self-healing, i.e., restoring their mechanical properties after deformation and failure, are gaining increasing research interest, as there is a continuous need towards extending the lifetime and improving the safety and performance of materials particularly in biomedical applications. Hydrogels are versatile materials that may allow self-healing through a variety of covalent and non-covalent bonding strategies. The structural recovery of physical gels has long been a topic of interest in soft materials physics and various supramolecular interactions can induce this kind of recovery. This review highlights the non-covalent strategies of building self-repairing hydrogels and the characterization of their mechanical properties. Potential applications and future prospects of these materials are also discussed.

  8. From micelle supramolecular assemblies in selective solvents to isoporous membranes

    KAUST Repository

    Nunes, Suzana Pereira

    2011-08-16

    The supramolecular assembly of PS-b-P4VP copolymer micelles induced by selective solvent mixtures was used to manufacture isoporous membranes. Micelle order in solution was confirmed by cryo-scanning electron microscopy in casting solutions, leading to ordered pore morphology. When dioxane, a solvent that interacts poorly with the micelle corona, was added to the solution, polymer-polymer segment contact was preferential, increasing the intermicelle contact. Immersion in water gave rise to asymmetric porous membranes with exceptional pore uniformity and high porosity. The introduction of a small number of carbon nanotubes to the casting solution improved the membrane stability and the reversibility of the gate response in the presence of different pH values. © 2011 American Chemical Society.

  9. Narrowing the diversification of supramolecular assemblies by preorganization.

    Science.gov (United States)

    Wang, Zhongyan; Liang, Chunhui; Shang, Yuna; He, Shuangshuang; Wang, Ling; Yang, Zhimou

    2018-03-13

    We designed and synthesized three phosphorylated peptides as precursors of the same peptide Nap-YYY. We found that different precursors led to different materials with almost identical chemical compositions at the final stages. Only Nap-YpYY could form very uniform nanofibers in a stable supramolecular hydrogel by enzyme-instructed self-assembly (EISA) at the physiological temperature (37 °C). In contrast, de-phosphorylation of the other two precursors (Nap-pYYY and Nap-YYpY) resulted in diverse nanostructures in metastable hydrogels with precipitates. The formation of uniform nanomaterials in the stable hydrogels was due to the preorganization property of the precursor Nap-YpYY, which facilitated rapid folding and accelerated the kinetics of hydrogelation of the resulting peptide Nap-YYY generated by the EISA process. Our study demonstrated the importance of the precursor for the self-assembly of nanomaterials and provided a useful strategy to manipulate them.

  10. Study of optical shuttering action in supramolecular hydrogen bonded nematogens

    Science.gov (United States)

    Kavitha, C.; Pongali Sathya Prabu, N.; Madhu Mohan, M. L. N.

    2012-11-01

    Supramolecular hydrogen bonded mesogens are formed between p-n-undecyloxy benzoic acid (11BAO) and p-n-alkyl benzoic acids (nBA, where n = 2-8). The isolated mesogens are characterized by distinct techniques in order to appreciate the optical, thermal, electrical, and dielectric properties. The optical tilt angle measurement is studied for all the members of this homologous series and is found to concur with the mean field theory predicted value. An interesting factor to notice is the observation of optical shuttering action in nematic phase of the entire series which privilege these materials to be used as light modulators. Dielectric measurements were carried out and the dispersion curves were discussed in terms of relaxation frequency and activation energies.

  11. From micelle supramolecular assemblies in selective solvents to isoporous membranes

    KAUST Repository

    Nunes, Suzana Pereira; Karunakaran, Madhavan; Neelakanda, Pradeep; Behzad, Ali Reza; Hooghan, Bobby; Sougrat, Rachid; He, Haoze; Peinemann, Klaus-Viktor

    2011-01-01

    The supramolecular assembly of PS-b-P4VP copolymer micelles induced by selective solvent mixtures was used to manufacture isoporous membranes. Micelle order in solution was confirmed by cryo-scanning electron microscopy in casting solutions, leading to ordered pore morphology. When dioxane, a solvent that interacts poorly with the micelle corona, was added to the solution, polymer-polymer segment contact was preferential, increasing the intermicelle contact. Immersion in water gave rise to asymmetric porous membranes with exceptional pore uniformity and high porosity. The introduction of a small number of carbon nanotubes to the casting solution improved the membrane stability and the reversibility of the gate response in the presence of different pH values. © 2011 American Chemical Society.

  12. Chiroptical studies on supramolecular chirality of molecular aggregates.

    Science.gov (United States)

    Sato, Hisako; Yajima, Tomoko; Yamagishi, Akihiko

    2015-10-01

    The attempts of applying chiroptical spectroscopy to supramolecular chirality are reviewed with a focus on vibrational circular dichroism (VCD). Examples were taken from gels, solids, and monolayers formed by low-molecular mass weight chiral gelators. Particular attention was paid to a group of gelators with perfluoroalkyl chains. The effects of the helical conformation of the perfluoroalkyl chains on the formation of chiral architectures are reported. It is described how the conformation of a chiral gelator was determined by comparing the experimental and theoretical VCD spectra together with a model proposed for the molecular aggregation in fibrils. The results demonstrate the potential utility of the chiroptical method in analyzing organized chiral aggregates. © 2015 Wiley Periodicals, Inc.

  13. Supramolecular "Trojan Horse" for Nuclear Delivery of Dual Anticancer Drugs.

    Science.gov (United States)

    Cai, Yanbin; Shen, Haosheng; Zhan, Jie; Lin, Mingliang; Dai, Liuhan; Ren, Chunhua; Shi, Yang; Liu, Jianfeng; Gao, Jie; Yang, Zhimou

    2017-03-01

    Nuclear delivery and accumulation are very important for many anticancer drugs that interact with DNA or its associated enzymes in the nucleus. However, it is very difficult for neutrally and negatively charged anticancer drugs such as 10-hydroxycamptothecine (HCPT). Here we report a simple strategy to construct supramolecular nanomedicines for nuclear delivery of dual synergistic anticancer drugs. Our strategy utilizes the coassembly of a negatively charged HCPT-peptide amphiphile and the positively charged cisplatin. The resulting nanomaterials behave as the "Trojan Horse" that transported soldiers (anticancer drugs) across the walls of the castle (cell and nucleus membranes). Therefore, they show improved inhibition capacity to cancer cells including the drug resistant cancer cell and promote the synergistic tumor suppression property in vivo. We envision that our strategy of constructing nanomaterials by metal chelation would offer new opportunities to develop nanomedicines for combination chemotherapy.

  14. Friction mediated by redox-active supramolecular connector molecules.

    Science.gov (United States)

    Bozna, B L; Blass, J; Albrecht, M; Hausen, F; Wenz, G; Bennewitz, R

    2015-10-06

    We report on a friction study at the nanometer scale using atomic force microscopy under electrochemical control. Friction arises from the interaction between two surfaces functionalized with cyclodextrin molecules. The interaction is mediated by connector molecules with (ferrocenylmethyl)ammonium end groups forming supramolecular complexes with the cyclodextrin molecules. With ferrocene connector molecules in solution, the friction increases by a factor of up to 12 compared to control experiments without connector molecules. The electrochemical oxidation of ferrocene to ferrocenium causes a decrease in friction owing to the lower stability of ferrocenium-cyclodextrin complex. Upon switching between oxidative and reduction potentials, a change in friction by a factor of 1.2-1.8 is observed. Isothermal titration calorimetry reveals fast dissociation and rebinding kinetics and thus an equilibrium regime for the friction experiments.

  15. Dynamic peptide libraries for the discovery of supramolecular nanomaterials

    Science.gov (United States)

    Pappas, Charalampos G.; Shafi, Ramim; Sasselli, Ivan R.; Siccardi, Henry; Wang, Tong; Narang, Vishal; Abzalimov, Rinat; Wijerathne, Nadeesha; Ulijn, Rein V.

    2016-11-01

    Sequence-specific polymers, such as oligonucleotides and peptides, can be used as building blocks for functional supramolecular nanomaterials. The design and selection of suitable self-assembling sequences is, however, challenging because of the vast combinatorial space available. Here we report a methodology that allows the peptide sequence space to be searched for self-assembling structures. In this approach, unprotected homo- and heterodipeptides (including aromatic, aliphatic, polar and charged amino acids) are subjected to continuous enzymatic condensation, hydrolysis and sequence exchange to create a dynamic combinatorial peptide library. The free-energy change associated with the assembly process itself gives rise to selective amplification of self-assembling candidates. By changing the environmental conditions during the selection process, different sequences and consequent nanoscale morphologies are selected.

  16. A redox-assisted supramolecular assembly of manganese oxide nanotube

    International Nuclear Information System (INIS)

    Tao Li; Sun Chenggao; Fan Meilian; Huang Caijuan; Wu Hailong; Chao Zisheng; Zhai Hesheng

    2006-01-01

    In this paper, we report the hydrothermal synthesis of manganese oxide nanotube from an aqueous medium of pH 7, using KMnO 4 and MnCl 2 as inorganic precursors, polyoxyethylene (10) nonyl phenyl ether (TX-10) a surfactant and acetaldehyde an additive. The characterization of X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED) and N 2 adsorption at 77 K (BET) reveals that the synthesized manganese oxide nanotube has a mesopore size of ca. 3.65 nm and a wall thickness of ca. 12 nm, with the wall being composed of microporous crystals of monoclinic manganite. The X-ray photoelectron spectroscopy (XPS) result demonstrates a decrease of the binding energy of the Mn 3+ in the manganese oxide nanotube, which may be related to both the nanotubular morphology and the crystalline pore wall. A mechanism of a redox-assisted supramolecular assembly, regulated by acetaldehyde, is postulated

  17. Supramolecular Approaches to Nanoscale Morphological Control in Organic Solar Cells

    Directory of Open Access Journals (Sweden)

    Alexander M. Haruk

    2015-06-01

    Full Text Available Having recently surpassed 10% efficiency, solar cells based on organic molecules are poised to become a viable low-cost clean energy source with the added advantages of mechanical flexibility and light weight. The best-performing organic solar cells rely on a nanostructured active layer morphology consisting of a complex organization of electron donating and electron accepting molecules. Although much progress has been made in designing new donor and acceptor molecules, rational control over active layer morphology remains a central challenge. Long-term device stability is another important consideration that needs to be addressed. This review highlights supramolecular strategies for generating highly stable nanostructured organic photovoltaic active materials by design.

  18. Supramolecular effects in dendritic systems containing photoactive groups

    Directory of Open Access Journals (Sweden)

    GIANLUCA CAMILLO AZZELLINI

    2000-03-01

    Full Text Available In this article are described dendritic structures containing photoactive groups at the surface or in the core. The observed supramolecular effects can be attributed to the nature of the photoactive group and their location in the dendritic architecture. The peripheric azobenzene groups in these dendrimeric compounds can be regarded as single residues that retain the spectroscopic and photochemical properties of free azobenzene moiety. The E and Z forms of higher generation dendrimer, functionalized with azobenzene groups, show different host ability towards eosin dye, suggesting the possibility of using such dendrimer in photocontrolled host-guest systems. The photophysical properties of many dendritic-bipyridine ruthenium complexes have been investigated. Particularly in aerated medium more intense emission and a longer excited-state lifetime are observed as compared to the parent unsubstituted bipyridine ruthenium complexes. These differences can be attributed to a shielding effect towards dioxygen quenching originated by the dendritic branches.

  19. Electrochemical supramolecular recognition of hemin-carbon composites

    Science.gov (United States)

    Le, Hien Thi Ngoc; Jeong, Hae Kyung

    2018-04-01

    Hemin-graphite oxide-carbon nanotube (hemin-GO-CNT) and hemin-thermally reduced graphite oxide-carbon nanotube (hemin-TRGO-CNT) composites are synthesized and investigated for the electrochemical supramolecular recognition by electron transfer between biomolecules (dopamine and hydrogen peroxide) and the composite electrodes. Redox reaction mechanisms of two composites with dopamine and hydrogen peroxide are explained in detail by using cyclic voltammetry and differential pulse voltammetry. Hemin-TRGO-CNT displays higher electrochemical detection for dopamine and hydrogen peroxide than that of hemin-GO-CNT, exhibiting enhancement of the electron transfer due to the effective immobilization of redox couple of hemin (Fe2+/Fe3+) on the TRGO-CNT surface.

  20. Supramolecular polymeric materials via cyclodextrin-guest interactions.

    Science.gov (United States)

    Harada, Akira; Takashima, Yoshinori; Nakahata, Masaki

    2014-07-15

    CONSPECTUS: Cyclodextrins (CDs) have many attractive functions, including molecular recognition, hydrolysis, catalysis, and polymerization. One of the most important uses of CDs is for the molecular recognition of hydrophobic organic guest molecules in aqueous solutions. CDs are desirable host molecules because they are environmentally benign and offer diverse functions. This Account demonstrates some of the great advances in the development of supramolecular materials through host-guest interactions within the last 10 years. In 1990, we developed topological supramolecular complexes with CDs, polyrotaxane, and CD tubes, and these preparation methods take advantage of self-organization between the CDs and the polymers. The combination of polyrotaxane with αCD forms a hydrogel through the interaction of αCDs with the OH groups on poly(ethylene glycol). We categorized these polyrotaxane chemistries within main chain type complexes. At the same time, we studied the interactions of side chain type supramolecular complexes with CDs. In these systems the guest molecules modified the polymers and selectively formed inclusion complexes with CDs. The systems that used low molecular weight compounds did not show such selectivity with CDs. The multivalency available within the complex cooperatively enhances the selective binding of CD with guest molecules via the polymer side chains, a phenomenon that is analogous to binding patterns observed in antigen-antibody complexes. To incorporate the molecular recognition properties of CDs within the polymer side chains, we first prepared stimuli-responsive sol-gel switching materials through host-guest interactions. We chose azobenzene derivatives for their response to light and ferrocene derivatives for their response to redox conditions. The supramolecular materials were both redox-responsive and self-healing, and these properties resulted from host-guest interactions. These sol-gels with built in switches gave us insight for

  1. Supramolecular Gold Metallogelators: The Key Role of Metallophilic Interactions

    Directory of Open Access Journals (Sweden)

    João Carlos Lima

    2014-12-01

    Full Text Available Gold metallogelators is an emerging area of research. The number of results published in the literature is still scarce. The majority of these gels is observed in organic solvents, and the potential applications are still to be explored. In this work, we present an overview about gold metallogelators divided in two different groups depending on the type of solvent used in the gelation process (organogelators and hydrogelators. A careful analysis of the data shows that aurophilic interactions are a common motif directly involved in gelation involving Au(I complexes. There are also some Au(III derivatives able to produce gels but in this case the organic ligands determine the aggregation process. A last section is included about the potential applications that have been reported until now with this new and amazing class of supramolecular assemblies.

  2. Porphyrinic supramolecular daisy chains incorporating pillar[5]arene-viologen host-guest interactions

    KAUST Repository

    Fathalla, Maher; Strutt, Nathan; Srinivasan, Sampath; Katsiev, Khabiboulakh; Hartlieb, Karel J.; Bakr, Osman; Stoddart, J. Fraser

    2015-01-01

    A porphyrin functionalised with pillar[5]arene and a viologen at its 5- and 15-meso positions assembles in a head-to-tail manner, producing linear supramolecular daisy chains in dichloromethane. At high concentrations, it forms an organogel which has been investigated by electron microscopy and rheological measurements, paving the way for the preparation of other functional supramolecular assemblies which harness viologen"⊂" pillararene host-guest interactions.

  3. Side-Chain Supramolecular Polymers Employing Conformer Independent Triple Hydrogen Bonding Arrays

    OpenAIRE

    Gooch, Adam; Murphy, Natasha S.; Thomson, Neil H.; Wilson, Andrew J.

    2013-01-01

    Derivatives of thymine have been extensively used to promote supramolecular materials assembly. Such derivatives can be synthetically challenging to access and may be susceptible to degradation. The current article uses a conformer-independent acceptor-donor-acceptor array (ureidopyrimidine) which forms moderate affinity interactions with diamidopyridine derivatives to effect supramolecular blend formation between polystyrene and poly(methyl methacrylate) polymers obtained by RAFT which have ...

  4. Porphyrinic supramolecular daisy chains incorporating pillar[5]arene-viologen host-guest interactions

    KAUST Repository

    Fathalla, Maher

    2015-05-18

    A porphyrin functionalised with pillar[5]arene and a viologen at its 5- and 15-meso positions assembles in a head-to-tail manner, producing linear supramolecular daisy chains in dichloromethane. At high concentrations, it forms an organogel which has been investigated by electron microscopy and rheological measurements, paving the way for the preparation of other functional supramolecular assemblies which harness viologen"⊂" pillararene host-guest interactions.

  5. Self-Assembly of Coordinative Supramolecular Polygons with Open Binding Sites.

    Science.gov (United States)

    Zheng, Yao-Rong; Wang, Ming; Kobayashi, Shiho; Stang, Peter J

    2011-04-27

    The design and synthesis of coordinative supramolecular polygons with open binding sites is described. Coordination-driven self-assembly of 2,6-bis(pyridin-4-ylethynyl)pyridine with 60° and 120° organoplatinum acceptors results in quantitative formation of a supramolecular rhomboid and hexagon, respectively, both bearing open pyridyl binding sites. The structures were determined by multinuclear ((31)P and (1)H) NMR spectroscopy and electrospray ionization (ESI) mass spectrometry, along with a computational study.

  6. A Dynamic Supramolecular System Exhibiting Substrate Selectivity in the Catalytic Epoxidation of Olefins

    DEFF Research Database (Denmark)

    Jonsson, Stefan; Odille, Fabrice G. J.; Norrby, Per-Ola

    2005-01-01

    A dynamic supramolecular system involving hydrogen bonding between a Mn(III) salen catalyst and a Zn(II) porphyrin receptor exhibits selectivity for pyridine appended cis-beta-substituted styrene derivatives over phenyl appended derivatives in a catalytic epoxidation reaction.......A dynamic supramolecular system involving hydrogen bonding between a Mn(III) salen catalyst and a Zn(II) porphyrin receptor exhibits selectivity for pyridine appended cis-beta-substituted styrene derivatives over phenyl appended derivatives in a catalytic epoxidation reaction....

  7. Molecular and supramolecular speciation of monoamide extractant systems

    International Nuclear Information System (INIS)

    Ferru, G.

    2012-01-01

    DEHiBA (N,N-di-(ethyl-2-hexyl)isobutyramide, a monoamide, was chosen as selective extractant for the recovery of uranium in the first cycle of the GANEX process, which aims to realize the grouped extraction of actinides in the second step of the process. The aim of this work is an improved description of monoamide organic solutions in alkane diluent after solutes extraction: water, nitric acid and uranyl nitrate. A parametric study was undertaken to characterize species at molecular scale (by IR spectroscopy, UV-visible spectroscopy, time-resolved laser-induced fluorescence spectroscopy, and electro-spray ionisation mass spectrometry) and at supramolecular scale (by vapor pressure osmometry and small angle X-ray scattering coupled to molecular dynamic simulations). Extraction isotherms were modelled taking into account the molecular and supramolecular speciation. These works showed that the organization of the organic solution depends on the amide concentration, the nature and the concentration of the extracted solute. Three regimes can be distinguished. 1/For extractant concentration less than 0.5 mol/L, monomers are predominate species. 2/ For extractant concentrations between 0.5 and 1 mol/L, small aggregates are formed containing 2 to 4 molecules of monoamide. 3/ For more concentrated solutions (greater than 1 mol/L), slightly larger species can be formed after water or nitric acid extraction. Concerning uranyl nitrate extraction, an important and strong organization of the organic phase is observed, which no longer allows the formation of well spherical defined aggregates. At molecular scale, complexes are not sensitive to the organization of the solution: the same species are observed, regardless of the solute and extractant concentrations in organic phase. (author) [fr

  8. Information processing in the CNS: a supramolecular chemistry?

    Science.gov (United States)

    Tozzi, Arturo

    2015-10-01

    How does central nervous system process information? Current theories are based on two tenets: (a) information is transmitted by action potentials, the language by which neurons communicate with each other-and (b) homogeneous neuronal assemblies of cortical circuits operate on these neuronal messages where the operations are characterized by the intrinsic connectivity among neuronal populations. In this view, the size and time course of any spike is stereotypic and the information is restricted to the temporal sequence of the spikes; namely, the "neural code". However, an increasing amount of novel data point towards an alternative hypothesis: (a) the role of neural code in information processing is overemphasized. Instead of simply passing messages, action potentials play a role in dynamic coordination at multiple spatial and temporal scales, establishing network interactions across several levels of a hierarchical modular architecture, modulating and regulating the propagation of neuronal messages. (b) Information is processed at all levels of neuronal infrastructure from macromolecules to population dynamics. For example, intra-neuronal (changes in protein conformation, concentration and synthesis) and extra-neuronal factors (extracellular proteolysis, substrate patterning, myelin plasticity, microbes, metabolic status) can have a profound effect on neuronal computations. This means molecular message passing may have cognitive connotations. This essay introduces the concept of "supramolecular chemistry", involving the storage of information at the molecular level and its retrieval, transfer and processing at the supramolecular level, through transitory non-covalent molecular processes that are self-organized, self-assembled and dynamic. Finally, we note that the cortex comprises extremely heterogeneous cells, with distinct regional variations, macromolecular assembly, receptor repertoire and intrinsic microcircuitry. This suggests that every neuron (or group of

  9. Supramolecular polyaniline hydrogel as a support for urease

    International Nuclear Information System (INIS)

    Słoniewska, Anna; Pałys, Barbara

    2014-01-01

    Supramolecular hydrogels of conducting polymers are successfully used in bioelectrochemistry because of their mechanical and swelling properties of gels added to the specific electron transport properties of conducting polymers. We have studied polyaniline-poly(styrene sulfonate) (PANI–PSS) hydrogel as a substrate for the urease. The hydrogels were synthesized at pH = 0 and pH = 5. PANI–PSS hydrogel is a supramolecular self-assembly material consisting of positively-charged PANI chains and negatively-charged PSS chains. The hydrogel was studied by cyclic voltammetry, infrared and Raman spectroscopy and Scanning Electron Microscopy (SEM). Raman spectra revealed presence of phenazine rings in the hydrogel structure. Phenazine rings form covalent cross-linkers contributing to the hydrogel mechanical stability. The covalent cross-linkers influence the cyclic voltammetry responses of the hydrogel in acidic media. We tested the activity of urease immobilized in the PANI–PSS hydrogel by the physical adsorption or by the covalent bonding with the carbodiimide reaction. The enzyme immobilized in hydrogels prepared at higher pH value reveals significantly higher sensitivity. The method of the enzyme immobilization has smaller impact on the sensitivity. All hydrogel sensors reveal largely higher sensitivity to urea comparing to urease immobilized in the typical electrochemically deposited PANI films. The sensitivity of urease covalently bond to the hydrogel obtained at pH = 5 was as high as 1693 μA/(mol dm 3 ). The sensor response was linear in the urea concentration range from 10 −4 to 7 × 10 −2 mol/dm 3

  10. Supramolecular Organocatalysis in Water Mediated by Macrocyclic Compounds

    Directory of Open Access Journals (Sweden)

    Margherita De Rosa

    2018-04-01

    Full Text Available In the last decades many efforts have been devoted to design supramolecular organocatalysts able to work in water as the reaction medium. The use of water as solvent provides promising benefits with respect to environmental impact. In this context, macrocyclic compounds played a role of primary importance thanks to their ease of synthesis and their molecular recognition abilities toward the reactants. The aim of this review is to give an overview of the recent advances in the field of supramolecular organocatalysis in water, focusing the attention on calixarene and cyclodextrins derivatives. Calixarenes and cyclodextrins, thanks to their hydrophobic cavities, are able to host selectively the substrates isolating they from the reaction environment. In addition, the synthetic versatilities of these macrocycles permits to introduce useful functional groups in close proximity of the hydrophobic binding sites. Regarding the cyclodextrins (CDs, we have here reviewed the their most recent uses as organocatalysts for the synthesis of heterocyclic compounds, in multi-component reactions and in carbon-carbon bond forming reactions. Examples have been reported in which CD catalysts are able to drive the regiochemistry of common organic reactions. In addition, cyclodextrins bearing catalytically active chiral groups, have shown excellent enantioselectivity in the catalysis of organic reactions. Recently reported results have shown that calixarene derivatives are able to accelerate organic reaction under “on-water” conditions with a significant selectivity toward the reactants. Under “on-water conditions” the hydrophobic effect, induced by insoluble calixarene derivatives, forces the reactants and the catalyst to aggregate and thus accelerating the reaction between them thanks to an amplification of weak secondary interactions. Regarding the use of water-soluble calixarene organocatalysts, we have here reviewed their role in the acceleration of

  11. Supramolecular Organocatalysis in Water Mediated by Macrocyclic Compounds

    Science.gov (United States)

    De Rosa, Margherita; La Manna, Pellegrino; Talotta, Carmen; Soriente, Annunziata; Gaeta, Carmine; Neri, Placido

    2018-04-01

    In the last decades many efforts have been devoted to design supramolecular organocatalysts able to work in water as the reaction medium. The use of water as solvent provides promising benefits with respect to environmental impact. In this context, macrocyclic compounds played a role of primary importance thanks to their ease of synthesis and their molecular recognition abilities toward the reactants. The aim of this review is to give an overview of the recent advances in the field of supramolecular organocatalysis in water, focusing the attention on calixarene and cyclodextrins derivatives. Calixarenes and cyclodextrins, thanks to their hydrophobic cavities, are able to host selectively the substrates isolating they from the reaction environment. In addition, the synthetic versatilities of these macrocycles permits to introduce useful functional groups in close proximity of the hydrophobic binding sites. Regarding the cyclodextrins (CDs), we have here reviewed the their most recent uses as organocatalysts for the synthesis of heterocyclic compounds, in multi-component reactions and in carbon-carbon bond forming reactions. Examples have been reported in which CD catalysts are able to drive the regiochemistry of common organic reactions. In addition, cyclodextrins bearing catalytically active chiral groups, have shown excellent enantioselectivity in the catalysis of organic reactions. Recently reported results have shown that calixarene derivatives are able to accelerate organic reaction under "on-water" conditions with a significant selectivity toward the reactants. Under "on-water conditions" the hydrophobic effect, induced by insoluble calixarene derivatives, forces the reactants and the catalyst to aggregate and thus accelerating the reaction between them thanks to an amplification of weak secondary interactions. Regarding the use of water-soluble calixarene organocatalysts, we have here reviewed their role in the acceleration of common organic reactions.

  12. Selective Organic and Organometallic Reactions in Water-Soluble Host-Guest Supramolecular Systems

    Energy Technology Data Exchange (ETDEWEB)

    Pluth, Michael D.; Raymond, Kenneth N.; Bergman, Robert G.

    2008-02-16

    Inspired by the efficiency and selectivity of enzymes, synthetic chemists have designed and prepared a wide range of host molecules that can bind smaller molecules with their cavities; this area has become known as 'supramolecular' or 'host-guest' chemistry. Pioneered by Lehn, Cram, Pedersen, and Breslow, and followed up by a large number of more recent investigators, it has been found that the chemical environment in each assembly - defined by the size, shape, charge, and functional group availability - greatly influences the guest-binding characteristics of these compounds. In contrast to the large number of binding studies that have been carried out in this area, the exploration of chemistry - especially catalytic chemistry - that can take place inside supramolecular host cavities is still in its infancy. For example, until the work described here was carried out, very few examples of organometallic reactivity inside supramolecular hosts were known, especially in water solution. For that reason, our group and the group directed by Kenneth Raymond decided to take advantage of our complementary expertise and attempt to carry out metal-mediated C-H bond activation reactions in water-soluble supramolecular systems. This article begins by providing background from the Raymond group in supramolecular coordination chemistry and the Bergman group in C-H bond activation. It goes on to report the results of our combined efforts in supramolecular C-H activation reactions, followed by extensions of this work into a wider range of intracavity transformations.

  13. Quantum-Chemical Insights into the Self-Assembly of Carbon-Based Supramolecular Complexes

    Directory of Open Access Journals (Sweden)

    Joaquín Calbo

    2018-01-01

    Full Text Available Understanding how molecular systems self-assemble to form well-organized superstructures governed by noncovalent interactions is essential in the field of supramolecular chemistry. In the nanoscience context, the self-assembly of different carbon-based nanoforms (fullerenes, carbon nanotubes and graphene with, in general, electron-donor molecular systems, has received increasing attention as a means of generating potential candidates for technological applications. In these carbon-based systems, a deep characterization of the supramolecular organization is crucial to establish an intimate relation between supramolecular structure and functionality. Detailed structural information on the self-assembly of these carbon-based nanoforms is however not always accessible from experimental techniques. In this regard, quantum chemistry has demonstrated to be key to gain a deep insight into the supramolecular organization of molecular systems of high interest. In this review, we intend to highlight the fundamental role that quantum-chemical calculations can play to understand the supramolecular self-assembly of carbon-based nanoforms through a limited selection of supramolecular assemblies involving fullerene, fullerene fragments, nanotubes and graphene with several electron-rich π-conjugated systems.

  14. Revolving supramolecular chiral structures powered by light in nanomotor-doped liquid crystals

    Science.gov (United States)

    Orlova, Tetiana; Lancia, Federico; Loussert, Charles; Iamsaard, Supitchaya; Katsonis, Nathalie; Brasselet, Etienne

    2018-04-01

    Molecular machines operated by light have been recently shown to be able to produce oriented motion at the molecular scale1,2 as well as do macroscopic work when embedded in supramolecular structures3-5. However, any supramolecular movement irremediably ceases as soon as the concentration of the interconverting molecular motors or switches reaches a photo-stationary state6,7. To circumvent this limitation, researchers have typically relied on establishing oscillating illumination conditions—either by modulating the source intensity8,9 or by using bespoke illumination arrangements10-13. In contrast, here we report a supramolecular system in which the emergence of oscillating patterns is encoded at the molecular level. Our system comprises chiral liquid crystal structures that revolve continuously when illuminated, under the action of embedded light-driven molecular motors. The rotation at the supramolecular level is sustained by the diffusion of the motors away from a localized illumination area. Above a critical irradiation power, we observe a spontaneous symmetry breaking that dictates the directionality of the supramolecular rotation. The interplay between the twist of the supramolecular structure and the diffusion14 of the chiral molecular motors creates continuous, regular and unidirectional rotation of the liquid crystal structure under non-equilibrium conditions.

  15. Supramolecular chemistry: from molecular information towards self-organization and complex matter

    International Nuclear Information System (INIS)

    Lehn, Jean-Marie

    2004-01-01

    Molecular chemistry has developed a wide range of very powerful procedures for constructing ever more sophisticated molecules from atoms linked by covalent bonds. Beyond molecular chemistry lies supramolecular chemistry, which aims at developing highly complex chemical systems from components interacting via non-covalent intermolecular forces. By the appropriate manipulation of these interactions, supramolecular chemistry became progressively the chemistry of molecular information, involving the storage of information at the molecular level, in the structural features, and its retrieval, transfer, and processing at the supramolecular level, through molecular recognition processes operating via specific interactional algorithms. This has paved the way towards apprehending chemistry also as an information science. Numerous receptors capable of recognizing, i.e. selectively binding, specific substrates have been developed, based on the molecular information stored in the interacting species. Suitably functionalized receptors may perform supramolecular catalysis and selective transport processes. In combination with polymolecular organization, recognition opens ways towards the design of molecular and supramolecular devices based on functional (photoactive, electroactive, ionoactive, etc) components. A step beyond preorganization consists in the design of systems undergoing self-organization, i.e. systems capable of spontaneously generating well-defined supramolecular architectures by self-assembly from their components. Self-organization processes, directed by the molecular information stored in the components and read out at the supramolecular level through specific interactions, represent the operation of programmed chemical systems. They have been implemented for the generation of a variety of discrete functional architectures of either organic or inorganic nature. Self-organization processes also give access to advanced supramolecular materials, such as

  16. Supramolecular coordination polymer formed from artificial light-harvesting dendrimer.

    Science.gov (United States)

    Lee, Hosoowi; Jeong, Young-Hwan; Kim, Joo-Ho; Kim, Inhye; Lee, Eunji; Jang, Woo-Dong

    2015-09-30

    We report the formation of supramolecular coordination polymers formed from multiporphyrin dendrimers (PZnPM; M = FB or Cu), composed of the focal freebase porphyrin (PFB) or cupper porphyrin (PCu) with eight zinc porphyrin (PZn) wings, and multipyridyl porphyrins (PyPM; M = FB or Cu), PFB or PCu with eight pyridyl groups, through multiple axial coordination interactions of pyridyl groups to PZns. UV-vis absorption spectra were recorded upon titration of PyPFB to PZnPFB. Differential spectra, obtained by subtracting the absorption of PZnPFB without guest addition as well as the absorption of PyPFB, exhibited clear isosbestic points with saturation binding at 1 equiv addition of PyPFB to PZnPFB. Job's plot analysis also indicated 1:1 stoichiometry for the saturation binding. The apparent association constant between PZnPFB and PyPFB (2.91 × 10(6) M(-1)), estimated by isothermal titration calorimetry, was high enough for fibrous assemblies to form at micromolar concentrations. The formation of a fibrous assembly from PZnPFB and PyPFB was visualized by atomic force microscopy and transmission electron microscopy (TEM). When a 1:1 mixture solution of PZnPFB and PyPFB (20 μM) in toluene was cast onto mica, fibrous assemblies with regular height (ca. 2 nm) were observed. TEM images obtained from 1:1 mixture solution of PZnPFB and PyPFB (0.1 wt %) in toluene clearly showed the formation of nanofibers with a regular diameter of ca. 6 nm. Fluorescence emission measurement of PZnPM indicated efficient intramolecular energy transfer from PZn to the focal PFB or PCu. By the formation of supramolecular coordination polymers, the intramolecular energy transfer changed to intermolecular energy transfer from PZnPM to PyPM. When the nonfluorescent PyPCu was titrated to fluorescent PZnPFB, fluorescence emission from the focal PFB was gradually decreased. By the titration of fluorescent PyPFB to nonfluorescent PZnPCu, fluorescence emission from PFB in PyPFB was gradually increased

  17. On the characterization of dynamic supramolecular systems: a general mathematical association model for linear supramolecular copolymers and application on a complex two-component hydrogen-bonding system.

    Science.gov (United States)

    Odille, Fabrice G J; Jónsson, Stefán; Stjernqvist, Susann; Rydén, Tobias; Wärnmark, Kenneth

    2007-01-01

    A general mathematical model for the characterization of the dynamic (kinetically labile) association of supramolecular assemblies in solution is presented. It is an extension of the equal K (EK) model by the stringent use of linear algebra to allow for the simultaneous presence of an unlimited number of different units in the resulting assemblies. It allows for the analysis of highly complex dynamic equilibrium systems in solution, including both supramolecular homo- and copolymers without the recourse to extensive approximations, in a field in which other analytical methods are difficult. The derived mathematical methodology makes it possible to analyze dynamic systems such as supramolecular copolymers regarding for instance the degree of polymerization, the distribution of a given monomer in different copolymers as well as its position in an aggregate. It is to date the only general means to characterize weak supramolecular systems. The model was fitted to NMR dilution titration data by using the program Matlab, and a detailed algorithm for the optimization of the different parameters has been developed. The methodology is applied to a case study, a hydrogen-bonded supramolecular system, salen 4+porphyrin 5. The system is formally a two-component system but in reality a three-component system. This results in a complex dynamic system in which all monomers are associated to each other by hydrogen bonding with different association constants, resulting in homo- and copolymers 4n5m as well as cyclic structures 6 and 7, in addition to free 4 and 5. The system was analyzed by extensive NMR dilution titrations at variable temperatures. All chemical shifts observed at different temperatures were used in the fitting to obtain the DeltaH degrees and DeltaS degrees values producing the best global fit. From the derived general mathematical expressions, system 4+5 could be characterized with respect to above-mentioned parameters.

  18. Self-assembling supramolecular systems of different symmetry formed by wedged macromolecular dendrons

    Energy Technology Data Exchange (ETDEWEB)

    Shcherbina, M. A., E-mail: shcherbina@ispm.ru; Bakirov, A. V. [Russian Academy of Sciences, Institute of Synthetic Polymer Materials (Russian Federation); Yakunin, A. N. [Karpov Institute of Physical Chemistry (Russian Federation); Percec, V. [University of Pennsylvania (United States); Beginn, U. [Universitaet Osnabrueck, Institut fuer Chemie (Germany); Moeller, M. [Institute for Technical and Macromolecular Chemistry (Germany); Chvalun, S. N. [Russian Academy of Sciences, Institute of Synthetic Polymer Materials (Russian Federation)

    2012-03-15

    The main stages of the self-assembling of supramolecular ensembles have been revealed by studying different functional wedged macromolecules: polymethacrylates with tapered side chains based on gallic acid, their macromonomers, and salts of 2,3,4- and 3,4,5-tris(dodecyloxy)benzenesulphonic acid. The first stage is the formation of individual supramolecular aggregates (long cylinders or spherical micelles) due to the weak noncovalent interactions of mesogenic groups and the subsequent ordering in these aggregates, which is accompanied by a decrease in the free energy of the system. Supramolecular aggregates, in turn, form 2D or 3D lattices. The shape of supramolecular aggregates and its change with temperature are delicate functions of the mesogen chemical structure; this circumstance makes it possible to rationally design complex self-assembling systems with the ability to respond smartly to external stimuli. X-ray diffraction analysis allows one to study the structure of supramolecular systems with different degrees of order, determine the type of mesophases formed by these systems, and reveal the phase behavior of the material. Particular attention has been paid to the method for reconstruction of electron density distribution from the relative reflection intensity. The application of a suite of experimental methods, including wide- and small-angle X-ray diffraction, molecular modeling, differential scanning calorimetry, and polarization optical microscopy, allows one to establish the relationship between the shape of the structural unit (molecule or molecular aggregate), the nature of the interaction, and the phase behavior of the material.

  19. Self-assembling supramolecular systems of different symmetry formed by wedged macromolecular dendrons

    International Nuclear Information System (INIS)

    Shcherbina, M. A.; Bakirov, A. V.; Yakunin, A. N.; Percec, V.; Beginn, U.; Möller, M.; Chvalun, S. N.

    2012-01-01

    The main stages of the self-assembling of supramolecular ensembles have been revealed by studying different functional wedged macromolecules: polymethacrylates with tapered side chains based on gallic acid, their macromonomers, and salts of 2,3,4- and 3,4,5-tris(dodecyloxy)benzenesulphonic acid. The first stage is the formation of individual supramolecular aggregates (long cylinders or spherical micelles) due to the weak noncovalent interactions of mesogenic groups and the subsequent ordering in these aggregates, which is accompanied by a decrease in the free energy of the system. Supramolecular aggregates, in turn, form 2D or 3D lattices. The shape of supramolecular aggregates and its change with temperature are delicate functions of the mesogen chemical structure; this circumstance makes it possible to rationally design complex self-assembling systems with the ability to respond smartly to external stimuli. X-ray diffraction analysis allows one to study the structure of supramolecular systems with different degrees of order, determine the type of mesophases formed by these systems, and reveal the phase behavior of the material. Particular attention has been paid to the method for reconstruction of electron density distribution from the relative reflection intensity. The application of a suite of experimental methods, including wide- and small-angle X-ray diffraction, molecular modeling, differential scanning calorimetry, and polarization optical microscopy, allows one to establish the relationship between the shape of the structural unit (molecule or molecular aggregate), the nature of the interaction, and the phase behavior of the material.

  20. [Study on meridian tropism of medicinal property theory for Chines medicines by supramolecular chemistry (I)].

    Science.gov (United States)

    He, Fu-yuan; Deng, Kai-wen; Yang, Yan-tao; Zhou, Yi-qun; Shi, Ji-lian; Liu, Wen-long; Tang, Yu

    2015-04-01

    In this paper, based on the special influence of supramolecular chemistry on the basic theory of Chinese medicines ( CM) , the authors further analyzed the history of meridian tropism and natural origins of CM organisms and explained CM ingredients and the universal regularity of the automatic action of the supramolecular "imprinting templates" hole channel structure. After entering human bodies, CMs, as the aggregation of supramolecular "imprinting templates" , automatically seek supramolecular subjects that are matched with their "imprinting templates" in human meridians and organs for the purpose of self-recognition, self-organization, self-assembly and self-replication, so as to generate specific efficacy in meridians and organs, which is reflected as the meridian tropism phenomena at macro level. This regularity can be studied by in vitro and in vivo experimental studies. In vitro methods are mostly supra molecular structure analysis and kinetic and thermodynamic parameter calculation; Whereas in vivo methods are dominated by the analysis on object component distribution, chromatopharmacodynamic parameters and network chromatopharmacodynamic parameters; Particularly, the acupoint-medicine method can simplify to study the supramolecular subject-object relations. Consequently, CM's'meridian tropism reveals the universal regularity for interactions of macromolecular and micromolecular "imprinting templates" of subjects and objects in natural organisms. As the first barrier for the material base of the CM theory and breakthrough in the modernization of the basic CM theory, meridian tropism plays an important role in studies on basic theories of the basic CM theory.

  1. Supramolecular ribbons from amphiphilic trisamides self-assembly.

    Science.gov (United States)

    García, Fátima; Buendía, Julia; Sánchez, Luis

    2011-08-05

    Two amphiphilic C(3)-symmetric OPE-based trisamides have been synthesized and their self-assembling features investigated in solution and on surface. Variable-temperature UV-vis experiments demonstrate the cooperative supramolecular polymerization of these trisamides that self-assemble by the operation of triple C═O···H-N H-bonding arrays between the amide functional groups and π-π stacking between the aromatic units. The helical organization of the aggregates has been demonstrated by circular dichroism at a concentration as low as 1 × 10(-4) M in acetonitrile. In the reported trisamides, the large hydrophobic aromatic core acts as a solvophobic module impeding the interaction between the polar TEG chains and the amide H-bonds. This strategy makes unnecessary the separation of the amide functional groups to the polar tri(ethylene glycol) chains by paraffinic fragments. Achiral trisamide 1 self-assembles into flat ribbon-like structures that experience an amplification of chirality by the addition of a small amount of chiral 2 that generates twisted stripes.

  2. Conductive Supramolecular Architecture Constructed from Polyoxovanadate Cluster and Heterocyclic Surfactant

    Directory of Open Access Journals (Sweden)

    Toshiyuki Misawa

    2018-01-01

    Full Text Available Proton-conductive solid electrolytes are significant for fuel-cell battery technology. Especially for use in motor vehicles, proton conductors which work at intermediate temperatures (373–673 K under an anhydrous atmosphere are desired to improve the fuel cell stability and efficiency. Inorganic–organic hybrid supramolecular architectures are a promising option for the realization of highly conductive proton conductors. Here, a hybrid layered crystal was synthesized for the first time by using an proton-containing decavanadate (V10 anion and a heterocyclic surfactant cation. A simple ion-exchange reaction led to the formation of an inorganic–organic hybrid of V10 by using dodecylpyridazinium (C12pda as the heterocyclic surfactant. Single crystal X-ray analyses revealed that four C12pda cations were associated with one V10 anion, which was a diprotonated species forming a one-dimensional infinite chain structure through hydrogen bonds. Anhydrous proton conductivity was investigated by alternating current (AC impedance spectroscopy in the range of 313–393 K, exhibiting a maximum value of 1.7 × 10−5 S cm−1 at 373 K.

  3. Synthetic Approach to biomolecular science by cyborg supramolecular chemistry.

    Science.gov (United States)

    Kurihara, Kensuke; Matsuo, Muneyuki; Yamaguchi, Takumi; Sato, Sota

    2018-02-01

    To imitate the essence of living systems via synthetic chemistry approaches has been attempted. With the progress in supramolecular chemistry, it has become possible to synthesize molecules of a size and complexity close to those of biomacromolecules. Recently, the combination of precisely designed supramolecules with biomolecules has generated structural platforms for designing and creating unique molecular systems. Bridging between synthetic chemistry and biomolecular science is also developing methodologies for the creation of artificial cellular systems. This paper provides an overview of the recently expanding interdisciplinary research to fuse artificial molecules with biomolecules, that can deepen our understanding of the dynamical ordering of biomolecules. Using bottom-up approaches based on the precise chemical design, synthesis and hybridization of artificial molecules with biological materials have been realizing the construction of sophisticated platforms having the fundamental functions of living systems. The effective hybrid, molecular cyborg, approaches enable not only the establishment of dynamic systems mimicking nature and thus well-defined models for biophysical understanding, but also the creation of those with highly advanced, integrated functions. This article is part of a Special Issue entitled "Biophysical Exploration of Dynamical Ordering of Biomolecular Systems" edited by Dr. Koichi Kato. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Inversion of Supramolecular Chirality by Sonication-Induced Organogelation

    Science.gov (United States)

    Maity, Sibaprasad; Das, Priyadip; Reches, Meital

    2015-01-01

    Natural helical structures have inspired the formation of well-ordered peptide-based chiral nanostructures in vitro. These structures have drawn much attention owing to their diverse applications in the area of asymmetric catalysts, chiral photonic materials, and nanoplasmonics. The self-assembly of two enantiomeric fluorinated aromatic dipeptides into ordered chiral fibrillar nanostructures upon sonication is described. These fibrils form organogels. Our results clearly indicate that fluorine-fluorine interactions play an important role in self-assembly. Circular dichroism analysis revealed that both peptides (peptides 1 and 2), containing two fluorines, depicted opposite cotton effects in their monomeric form compared with their aggregated form. This shows that supramolecular chirality inversion took place during the stimuli-responsive self-aggregation process. Conversely, peptide 3, containing one fluorine, did not exhibit chirality inversion in sonication-induced organogelation. Therefore, our results clearly indicate that fluorination plays an important role in the organogelation process of these aromatic dipeptides. Our findings may have broad implications regarding the design of chiral nanostructures for possible applications such as chiroptical switches, asymmetric catalysis, and chiral recognitions. PMID:26553508

  5. Electropolymerized supramolecular tetraruthenated porphyrins applied as a voltammetric sensor

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Monize M. da; Ribeiro, Gabriel H.; Faria, Anizio M. de; Bogado, Andre L.; Dinelli, Luis R., E-mail: dinelli@pontal.ufu.br [Universidade Federal de Uberlandia (UFU), Ituiutaba, MG (Brazil). Faculdade de Ciencias Integradas do Pontal; Batista, Alzir A. [Universidade Federal de Sao Carlos (UFSCar), SP (Brazil). Departamento de Quimica

    2013-11-15

    Porphyrin 5,10,15,20-Tetra(4-pyridyl)manganese(III), [Mn-TPyP(H{sub 2}O){sub 2}]PF{sub 6}, and electropolymerized supramolecular porphyrins (ESP), {l_brace}Mn-TPyP(H{sub 2}O){sub 2}[RuCl{sub 3}(dppb)]{sub 4}{r_brace}PF{sub 6} (dppb = 1,4-bis(diphenylphosphine)butane), were synthesized and characterized. A thin solid film of ESP was obtained on a glass carbon electrode surface by a cyclic voltammetry method. The peak current increased with the number of voltammetric cycles, which shows a typical behavior of the species being adsorbed on the surface of the electrode. Cyclic voltammetry was also employed for acetaminophen quantification using an ESP modified electrode. The modified electrode shows a linear relationship between the anodic peak current and the concentration of acetaminophen (in the rage 0.05 to 0.7 mmol L{sup -1}. The performance of the modified electrode was verified by the determination of acetaminophen in a commercial pharmaceutical product and the results were in good agreement with those obtained by a control HPLC method. (author)

  6. Artificial Nacre from Supramolecular Assembly of Graphene Oxide.

    Science.gov (United States)

    Wang, Yang; Li, Ting; Ma, Piming; Zhang, Shengwen; Zhang, Hongji; Du, Mingliang; Xie, Yi; Chen, Mingqing; Dong, Weifu; Ming, Weihua

    2018-06-14

    Inspired by the "brick-and-mortar" structure and remarkable mechanical performance of nacre, many efforts have been devoted to fabricating nacre-mimicking materials. Herein, a class of graphene oxide (GO) based artificial nacre material with quadruple hydrogen-bonding interactions was fabricated by functionalization of polydopamine-capped graphene oxide (PDG) with 2-ureido-4[1 H]-pyrimidinone (UPy) self-complementary quadruple hydrogen-bonding units followed by supramolecular assembly process. The artificial nacre displays a strict "brick-and-mortar" structure, with PDG nanosheets as the brick and UPy units as the mortar. The resultant nanocomposite shows an excellent balance of strength and toughness. Because of the strong strengthening via quadruple hydrogen bonding, the tensile strength and toughness can reach 325.6 ± 17.8 MPa and 11.1 ± 1.3 MJ m -3 , respectively, thus exceeding natural nacre, and reaching 3.6 and 10 times that of a pure GO artificial nacre. Furthermore, after further H 2 O treatment, the resulting H 2 O-treated PDG-UPy actuator displays significant bending actuations when driven by heat. This work provides a pathway for the development of artificial nacre for their potential applications in energy conversion, temperature sensor, and thermo-driven actuator.

  7. Energy Landscapes for the Self-Assembly of Supramolecular Polyhedra

    Science.gov (United States)

    Russell, Emily R.; Menon, Govind

    2016-06-01

    We develop a mathematical model for the energy landscape of polyhedral supramolecular cages recently synthesized by self-assembly (Sun et al. in Science 328:1144-1147, 2010). Our model includes two essential features of the experiment: (1) geometry of the organic ligands and metallic ions; and (2) combinatorics. The molecular geometry is used to introduce an energy that favors square-planar vertices (modeling {Pd}^{2+} ions) and bent edges with one of two preferred opening angles (modeling boomerang-shaped ligands of two types). The combinatorics of the model involve two-colorings of edges of polyhedra with four-valent vertices. The set of such two-colorings, quotiented by the octahedral symmetry group, has a natural graph structure and is called the combinatorial configuration space. The energy landscape of our model is the energy of each state in the combinatorial configuration space. The challenge in the computation of the energy landscape is a combinatorial explosion in the number of two-colorings of edges. We describe sampling methods based on the symmetries of the configurations and connectivity of the configuration graph. When the two preferred opening angles encompass the geometrically ideal angle, the energy landscape exhibits a very low-energy minimum for the most symmetric configuration at equal mixing of the two angles, even when the average opening angle does not match the ideal angle.

  8. Supramolecular Affinity Chromatography for Methylation-Targeted Proteomics.

    Science.gov (United States)

    Garnett, Graham A E; Starke, Melissa J; Shaurya, Alok; Li, Janessa; Hof, Fraser

    2016-04-05

    Proteome-wide studies of post-translationally methylated species using mass spectrometry are complicated by high sample diversity, competition for ionization among peptides, and mass redundancies. Antibody-based enrichment has powered methylation proteomics until now, but the reliability, pan-specificity, polyclonal nature, and stability of the available pan-specific antibodies are problematic and do not provide a standard, reliable platform for investigators. We have invented an anionic supramolecular host that can form host-guest complexes selectively with methyllysine-containing peptides and used it to create a methylysine-affinity column. The column resolves peptides on the basis of methylation-a feat impossible with a comparable commercial cation-exchange column. A proteolyzed nuclear extract was separated on the methyl-affinity column prior to standard proteomics analysis. This experiment demonstrates that such chemical methyl-affinity columns are capable of enriching and improving the analysis of methyllysine residues from complex protein mixtures. We discuss the importance of this advance in the context of biomolecule-driven enrichment methods.

  9. Supra-molecular networks for CO2 capture

    Science.gov (United States)

    Sadowski, Jerzy; Kestell, John

    Utilizing capabilities of low-energy electron microscopy (LEEM) for non-destructive interrogation of the real-time molecular self-assembly, we have investigated supramolecular systems based on carboxylic acid-metal complexes, such as trimesic and mellitic acid, doped with transition metals. Such 2D networks can act as host systems for transition-metal phthalocyanines (MPc; M = Fe, Ti, Sc). The electrostatic interactions of CO2 molecules with transition metal ions can be tuned by controlling the type of TM ion and the size of the pore in the host network. We further applied infrared reflection-absorption spectroscopy (IRRAS) to determine of the molecular orientation of the functional groups and the whole molecule in the 2D monolayers of carboxylic acid. The kinetics and mechanism of the CO2 adsorption/desorption on the 2D molecular network, with and without the TM ion doping, have been also investigated. This research used resources of the Center for Functional Nanomaterials, which is the U.S. DOE Office of Science User Facility, at Brookhaven National Laboratory under Contract No. DE-SC0012704.

  10. Spectro-microscopic study of the formation of supramolecular networks

    Science.gov (United States)

    Sadowski, Jerzy T.

    2015-03-01

    Metal-organic frameworks (MOFs) are emerging as a new class of materials for CO2 capture. There are many fundamental questions, including the optimum pore size and arrangement of the molecules in the structure to achieve highest CO2 uptake. As only the surface is of interest for potential applications such as heterogeneous catalysis, nano-templating, and sensing, 2D analogs of MOFs can serve as good model systems. Utilizing capabilities of LEEM/PEEM for non-destructive interrogation of the real-time molecular self-assembly, we investigated supramolecular systems based on carboxylic acid-metal complexes, such as trimesic and mellitic acid, doped with transition metals. Such 2D networks act as host systems for transition-metal phthalocyanines (MPc; M = Fe, Ti, Sc) and the electrostatic interactions of CO2 molecules with transition metal ions, can be tuned by controlling the type of TM ion and the size of the pore in the host network. The understanding of directed self-assembly by controlling the molecule-substrate interaction can enable us to engineer the pore size and density, and thus tune the host's chemical activity. Research carried out at the Center for Functional Nanomaterials and National Synchrotron Light Source, Brookhaven National Laboratory, which are supported by the U.S. Department of Energy, Office of Basic Energy Sciences, under Contract No. DE-AC02-98CH10.

  11. Strong supramolecular control over protein self-assembly using a polyamine decorated β-cyclodextrin as synthetic recognition element

    NARCIS (Netherlands)

    Uhlenheuer, D.A.; Milroy, L.G.; Neirynck, P.; Brunsveld, L.

    2011-01-01

    The supramolecular host molecule heptakis-[6-deoxy-6-(2-aminoethylsulfanyl)]-ß-cyclodextrin provides strong control over protein self-assembly in synthetic supramolecular protein constructs. Mono-functionalization of this modified ß-cyclodextrin with a cysteine residue allows for site-selective

  12. Nanoparticles functionalized with supramolecular host-guest systems for nanomedicine and healthcare.

    Science.gov (United States)

    Wu, Zilong; Song, Nan; Menz, Ryan; Pingali, Bharadwaj; Yang, Ying-Wei; Zheng, Yuebing

    2015-05-01

    Synthetic macrocyclic host compounds can interact with suitable guest molecules via noncovalent interactions to form functional supramolecular systems. With the synergistic integration of the response of molecules and the unique properties at the nanoscale, nanoparticles functionalized with the host-guest supramolecular systems have shown great potentials for a broad range of applications in the fields of nanoscience and nanotechnology. In this review article, we focus on the applications of the nanoparticles functionalized with supramolecular host-guest systems in nanomedicine and healthcare, including therapeutic delivery, imaging, sensing and removal of harmful substances. A large number of examples are included to elucidate the working mechanisms, advantages, limitations and future developments of the nanoparticle-supramolecule systems in these applications.

  13. Collaborative routes to clarifying the murky waters of aqueous supramolecular chemistry.

    Science.gov (United States)

    Cremer, Paul S; Flood, Amar H; Gibb, Bruce C; Mobley, David L

    2017-12-19

    On planet Earth, water is everywhere: the majority of the surface is covered with it; it is a key component of all life; its vapour and droplets fill the lower atmosphere; and even rocks contain it and undergo geomorphological changes because of it. A community of physical scientists largely drives studies of the chemistry of water and aqueous solutions, with expertise in biochemistry, spectroscopy and computer modelling. More recently, however, supramolecular chemists - with their expertise in macrocyclic synthesis and measuring supramolecular interactions - have renewed their interest in water-mediated non-covalent interactions. These two groups offer complementary expertise that, if harnessed, offer to accelerate our understanding of aqueous supramolecular chemistry and water writ large. This Review summarizes the state-of-the-art of the two fields, and highlights where there is latent chemical space for collaborative exploration by the two groups.

  14. Collaborative routes to clarifying the murky waters of aqueous supramolecular chemistry

    Science.gov (United States)

    Cremer, Paul S.; Flood, Amar H.; Gibb, Bruce C.; Mobley, David L.

    2018-01-01

    On planet Earth, water is everywhere: the majority of the surface is covered with it; it is a key component of all life; its vapour and droplets fill the lower atmosphere; and even rocks contain it and undergo geomorphological changes because of it. A community of physical scientists largely drives studies of the chemistry of water and aqueous solutions, with expertise in biochemistry, spectroscopy and computer modelling. More recently, however, supramolecular chemists -- with their expertise in macrocyclic synthesis and measuring supramolecular interactions -- have renewed their interest in water-mediated non-covalent interactions. These two groups offer complementary expertise that, if harnessed, offer to accelerate our understanding of aqueous supramolecular chemistry and water writ large. This Review summarizes the state-of-the-art of the two fields, and highlights where there is latent chemical space for collaborative exploration by the two groups.

  15. Supramolecular assembly/reassembly processes: molecular motors and dynamers operating at surfaces.

    Science.gov (United States)

    Ciesielski, Artur; Samorì, Paolo

    2011-04-01

    Among the many significant advances within the field of supramolecular chemistry over the past decades, the development of the so-called "dynamers" features a direct relevance to materials science. Defined as "combinatorial dynamic polymers", dynamers are constitutional dynamic systems and materials resulting from the application of the principles of supramolecular chemistry to polymer science. Like supramolecular materials in general, dynamers are reversible dynamic multifunctional architectures, capable of modifying their constitution by exchanging, recombining, incorporating components. They may exhibit a variety of novel properties and behave as adaptive materials. In this review we focus on the design of responsive switchable monolayers, i.e. monolayers capable to undergo significant changes in their physical or chemical properties as a result of external stimuli. Scanning tunneling microscopy studies provide direct evidence with a sub-nanometre resolution, on the formation and dynamic response of these self-assembled systems featuring controlled geometries and properties.

  16. Supra-molecular Association and Polymorphic Behaviour In Systems Containing Bile Acid Salts

    Directory of Open Access Journals (Sweden)

    Camillo La Mesa

    2007-08-01

    Full Text Available A wide number of supra-molecular association modes are observed in mixtures containing water and bile salts, BS, (with, eventually, other components. Molecular or micellar solutions transform into hydrated solids, fibres, lyotropic liquid crystals and/or gels by raising the concentration, the temperature, adding electrolytes, surfactants, lipids and proteins. Amorphous or ordered phases may be formed accordingly. The forces responsible for this very rich polymorphism presumably arise from the unusual combination of electrostatic, hydrophobic and hydrogen-bond contributions to the system stability, with subsequent control of the supra-molecular organisation modes. The stabilising effect due to hydrogen bonds does not occur in almost all surfactants or lipids and is peculiar to bile acids and salts. Some supra-molecular organisation modes, supposed to be related to malfunctions and dis-metabolic diseases in vivo, are briefly reported and discussed.

  17. Visualization of Stereoselective Supramolecular Polymers by Chirality-Controlled Energy Transfer.

    Science.gov (United States)

    Sarkar, Aritra; Dhiman, Shikha; Chalishazar, Aditya; George, Subi J

    2017-10-23

    Chirality-driven self-sorting is envisaged to efficiently control functional properties in supramolecular materials. However, the challenge arises because of a lack of analytical methods to directly monitor the enantioselectivity of the resulting supramolecular assemblies. Presented herein are two fluorescent core-substituted naphthalene-diimide-based donor and acceptor molecules with minimal structural mismatch and they comprise strong self-recognizing chiral motifs to determine the self-sorting process. As a consequence, stereoselective supramolecular polymerization with an unprecedented chirality control over energy transfer has been achieved. This chirality-controlled energy transfer has been further exploited as an efficient probe to visualize microscopically the chirality driven self-sorting. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Stoichiometry-Controlled Inversion of Supramolecular Chirality in Nanostructures Co-assembled with Bipyridines.

    Science.gov (United States)

    Wang, Fang; Feng, Chuan-Liang

    2018-02-01

    To control supramolecular chirality of the co-assembled nanostructures, one of the remaining issues is how stoichiometry of the different molecules involved in co-assembly influence chiral transformation. Through co-assembly of achiral 1,4-bis(pyrid-4-yl)benzene and chiral phenylalanine-glycine derivative hydrogelators, stoichiometry is found to be an effective tool for controlling supramolecular chirality inversion processes. This inversion is mainly mediated by a delicate balance between intermolecular hydrogen bonding interactions and π-π stacking of the two components, which may subtly change the stacking of the molecules, in turn, the self-assembled nanostructures. This study exemplifies a simplistic way to invert the handedness of chiral nanostructures and provide fundamental understanding of the inherent principles of supramolecular chirality. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Supramolecular Rotor and Translator at Work: On-Surface Movement of Single Atoms.

    Science.gov (United States)

    Ohmann, Robin; Meyer, Jörg; Nickel, Anja; Echeverria, Jorge; Grisolia, Maricarmen; Joachim, Christian; Moresco, Francesca; Cuniberti, Gianaurelio

    2015-08-25

    A supramolecular nanostructure composed of four 4-acetylbiphenyl molecules and self-assembled on Au (111) was loaded with single Au adatoms and studied by scanning tunneling microscopy at low temperature. By applying voltage pulses to the supramolecular structure, the loaded Au atoms can be rotated and translated in a controlled manner. The manipulation of the gold adatoms is driven neither by mechanical interaction nor by direct electronic excitation. At the electronic resonance and driven by the tunneling current intensity, the supramolecular nanostructure performs a small amount of work of about 8 × 10(-21) J, while transporting the single Au atom from one adsorption site to the next. Using the measured average excitation time necessary to induce the movement, we determine the mechanical motive power of the device, yielding about 3 × 10(-21) W.

  20. Enzymatic Dissolution of Biocomposite Solids Consisting of Phosphopeptides to Form Supramolecular Hydrogels

    KAUST Repository

    Shi, Junfeng; Yuan, Dan; Haburcak, Richard; Zhang, Qiang; Zhao, Chao; Zhang, Xixiang; Xu, Bing

    2015-01-01

    Enzyme-catalyzed dephosphorylation is essential for biomineralization and bone metabolism. Here we report the exploration of using enzymatic reaction to transform biocomposites of phosphopeptides and calcium (or strontium) ions to supramolecular hydrogels as a mimic of enzymatic dissolution of biominerals. 31P NMR shows that strong affinity between the phosphopeptides and alkaline metal ions (e.g., Ca2+ or Sr2+) induces the formation of biocomposites as precipitates. Electron microscopy reveals that the enzymatic reaction regulates the morphological transition from particles to nanofibers. Rheology confirms the formation of a rigid hydrogel. As the first example of enzyme-instructed dissolution of a solid to form supramolecular nanofibers/hydrogels, this work provides an approach to generate soft materials with desired properties, expands the application of supramolecular hydrogelators, and offers insights to control the demineralization of calcified soft tissues.

  1. Enzymatic Dissolution of Biocomposite Solids Consisting of Phosphopeptides to Form Supramolecular Hydrogels

    KAUST Repository

    Shi, Junfeng

    2015-10-14

    Enzyme-catalyzed dephosphorylation is essential for biomineralization and bone metabolism. Here we report the exploration of using enzymatic reaction to transform biocomposites of phosphopeptides and calcium (or strontium) ions to supramolecular hydrogels as a mimic of enzymatic dissolution of biominerals. 31P NMR shows that strong affinity between the phosphopeptides and alkaline metal ions (e.g., Ca2+ or Sr2+) induces the formation of biocomposites as precipitates. Electron microscopy reveals that the enzymatic reaction regulates the morphological transition from particles to nanofibers. Rheology confirms the formation of a rigid hydrogel. As the first example of enzyme-instructed dissolution of a solid to form supramolecular nanofibers/hydrogels, this work provides an approach to generate soft materials with desired properties, expands the application of supramolecular hydrogelators, and offers insights to control the demineralization of calcified soft tissues.

  2. A supramolecular strategy for self-mobile adsorption sites in affinity membrane.

    Science.gov (United States)

    Lin, Ligang; Dong, Meimei; Liu, Chunyu; Wei, Chenjie; Wang, Yuanyuan; Sun, Hui; Ye, Hui

    2014-09-01

    Disclosed here is the design of a novel supramolecular membrane with self-mobile adsorption sites for biomolecules purification. In the 3D micropore channels of membrane matrix, the ligands are conjugated onto the cyclic compounds in polyrotaxanes for protein adsorption. During membrane filtration, the adsorption sites can rotate and/or slide along the axial chain, which results in the enhanced adsorption capacity. The excellent performance of supra-molecular membrane is related with the dynamic working manner of adsorption sites, which plays a crucial role on avoiding spatial mismatching and short-circuit effect. The supra-molecular strategy described here has general suggestions for the "sites" involved technologies such as catalysis, adsorption, and sensors, which is of broad interest. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Surface-Assisted Self-Assembly Strategies Leading to Supramolecular Hydrogels.

    Science.gov (United States)

    Vigier-Carrière, Cécile; Boulmedais, Fouzia; Schaaf, Pierre; Jierry, Loïc

    2018-02-05

    Localized molecular self-assembly processes leading to the growth of nanostructures exclusively from the surface of a material is one of the great challenges in surface chemistry. In the last decade, several works have been reported on the ability of modified or unmodified surfaces to manage the self-assembly of low-molecular-weight hydrogelators (LMWH) resulting in localized supramolecular hydrogel coatings mainly based on nanofiber architectures. This Minireview highlights all strategies that have emerged recently to initiate and localize LMWH supramolecular hydrogel formation, their related fundamental issues and applications. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Self-assemblage and post-radiation recovery of cell supramolecular structures

    International Nuclear Information System (INIS)

    Grodzinskij, D.M.; Kolomiets, K.D.

    1979-01-01

    The role of the molecular equation and self-assemblage in post-radiation chromatin recovery of meristematic cells of pea rootlets is shown. Found are the two repair types at the chromatin level by fractionating of the radiation dose. The first type comprises transient processes including DNA repair, the second type comprises processes including biosynthesis of the chromatin components and proteins, in the first place. The role of protein biosynthesis in the process of recovery of the chromatin supramolecular structure is shown. The improved radiostability of chromatin self-assemblage is characteristic for the level of its subunits. The supramolecular chromatin structure of the other levels has less radiostability

  5. TOPICAL REVIEW: Metallo-supramolecular modules as a paradigm for materials science

    Directory of Open Access Journals (Sweden)

    Dirk G Kurth

    2008-01-01

    Full Text Available Metal ion coordination in discrete or extended metallo-supramolecular assemblies offers ample opportunity to fabricate and study devices and materials that are equally important for fundamental research and new technologies. Metal ions embedded in a specific ligand field offer diverse thermodynamic, kinetic, chemical, physical and structural properties that make these systems promising candidates for active components in functional materials. A key challenge is to improve and develop methodologies for placing these active modules in suitable device architectures, such as thin films or mesophases. This review highlights recent developments in extended, polymeric metallo-supramolecular systems and discrete polyoxometalates with an emphasis on materials science.

  6. Supramolecular chemistry and chemical warfare agents: from fundamentals of recognition to catalysis and sensing.

    Science.gov (United States)

    Sambrook, M R; Notman, S

    2013-12-21

    Supramolecular chemistry presents many possible avenues for the mitigation of the effects of chemical warfare agents (CWAs), including sensing, catalysis and sequestration. To-date, efforts in this field both to study fundamental interactions between CWAs and to design and exploit host systems remain sporadic. In this tutorial review the non-covalent recognition of CWAs is considered from first principles, including taking inspiration from enzymatic systems, and gaps in fundamental knowledge are indicated. Examples of synthetic systems developed for the recognition of CWAs are discussed with a focus on the supramolecular complexation behaviour and non-covalent approaches rather than on the proposed applications.

  7. Transuranic Hybrid Materials: Crystallographic and Computational Metrics of Supramolecular Assembly

    Energy Technology Data Exchange (ETDEWEB)

    Surbella, Robert G. [Department; Ducati, Lucas C. [Department; Pellegrini, Kristi L. [Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, Washington 99354, United States; McNamara, Bruce K. [Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, Washington 99354, United States; Autschbach, Jochen [Department; Schwantes, Jon M. [Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, Washington 99354, United States; Cahill, Christopher L. [Department

    2017-07-26

    A family of twelve supramolecular [AnO2Cl4]2- (An = U, Np, Pu) containing compounds assembled via hydrogen and halogen bonds donated by substituted 4-X-pyridinium cations (X = H, Cl, Br, I) is reported. These materials were prepared from a room-temperature synthesis wherein crystallization of unhydrolyzed and valence pure [An(VI)O2Cl4]2- (An = U, Np, Pu) tectons are the norm. We present a hierarchy of assembly criteria based on crystallographic observations, and subsequently quantify the strengths of the non-covalent interactions using Kohn-Sham density functional calculations. We provide, for the first time, a detailed description of the electrostatic potentials (ESPs) of the actinyl tetrahalide dianions and reconcile crystallographically observed structural motifs and non-covalent interaction (NCI) acceptor-donor pairings. Our findings indicate that the average electrostatic potential across the halogen ligands (the acceptors) changes by only ~2 kJ mol-1 across the AnO22+ series, indicating the magnitude of the potential is independent of the metal center. The role of the cation is therefore critical in directing structural motifs and dictating the resulting hydrogen and halogen bond strengths, the former being stronger due to the positive charge centralized on the pyridyl nitrogen N-H+. Subsequent analyses using the Quantum theory of atoms in molecules (QTAIM) and natural bond orbital (NBO) approaches support this conclusion and highlight the structure directing role of the cations. Whereas one can infer that the 2 Columbic attraction is the driver for assembly, the contribution of the non-covalent interaction is to direct the molecular-level arrangement (or disposition) of the tectons.

  8. Artificial muscle-like function from hierarchical supramolecular assembly of photoresponsive molecular motors

    NARCIS (Netherlands)

    Chen, Jiawen; Leung, Franco King-Chi; Stuart, Marc C A; Kajitani, Takashi; Fukushima, Takanori; van der Giessen, Erik; Feringa, Ben L

    A striking feature of living systems is their ability to produce motility by amplification of collective molecular motion from the nanoscale up to macroscopic dimensions. Some of nature's protein motors, such as myosin in muscle tissue, consist of a hierarchical supramolecular assembly of very large

  9. Role of supramolecular cellulose structures in enzymatic hydrolysis of plant cell walls

    DEFF Research Database (Denmark)

    Thygesen, Lisbeth Garbrecht; Hidayat, Budi Juliman; Johansen, Katja Salomon

    2011-01-01

    The study of biomass deconstruction by enzymatic hydrolysis has hitherto not focussed on the importance of supramolecular structures of cellulose. In lignocellulose fibres, regions with a different organisation of the microfibrils are present. These regions are called dislocations or slip planes ...... the initial part of enzymatic hydrolysis of cellulose. The implications of this phenomenon have not yet been recognized or explored within cellulosic biofuels....

  10. Supramolecular Control of Oligothienylenevinylene-Fullerene Interactions: Evidence for a Ground-State EDA Complex

    NARCIS (Netherlands)

    McClenaghan, N.D.; Grote, Z.; Darriet, K.; Zimine, M.Y.; Williams, R.M.; De Cola, L.; Bassani, D.M.

    2005-01-01

    Complementary hydrogen-bonding interactions between a barbituric acid-substituted fullerene derivative (1) and corresponding receptor (2) bearing thienylenevinylene units are used to assemble a 1:1 supramolecular complex ( K ) 5500 M-1). Due to the close proximity of the redox-active moieties within

  11. The fifth solvatomorph of gallic acid with a supramolecular channel structure: Structural complexity and phase transitions

    Science.gov (United States)

    Thomas, Sajesh P.; Kaur, Ramanpreet; Kaur, Jassjot; Sankolli, Ravish; Nayak, Susanta K.; Guru Row, Tayur N.

    2013-01-01

    A new solvatomorph of gallic acid was generated using chiral additive technique and characterized by single crystal and powder X-ray diffraction, C-13 NMR, IR spectroscopic techniques and thermal analysis. The supramolecular channels formed by hexameric motifs of gallic acid and solvent molecules contain highly disordered solvent molecules with fractional occupancies.

  12. Analysis of supramolecular surface nanostructures using secondary ion mass spectrometry (poster)

    International Nuclear Information System (INIS)

    Halaszova, S.; Velic, D.

    2013-01-01

    Our system consists of host molecules β-cyclodextrin (C 42 H 70 O 35 ), of implemented Iron nanoparticles (guest). Whole supramolecular complex is placed on a gold substrate. In our project we work with monotiolated β-cyclodextrin (C 42 H 70 O 34 S), consisting of seven α-D-1-4 glucopyranose units. Cyclodextrins have been selected deliberately because of their ability to form inclusion complexes .They are also capable of forming structures similar to self-assembly monolayers. To study the formation of these supramolecular surface nanostructures mass secondary ion spectrometry is used. With this technique fragmentation of monotiolated β-cyclodextrin and the presence of the supramolecular complex on a gold surface can be examined. The observed fragments of monotiolated cyclodextrines films can be divided into three groups: Au X H Y S Z , fragments originating from cyclodextrin molecules associated with Au. Fragments as (C 42 H 70 O 34 S)Na + , (C 42 H 70 O 35 )Na + and (AuC 42 H 69 O 34 S)Na + were identified as well as fragments thereof in cationized form with K + . The main objective of the project is a detailed study and preparation of supramolecular nanostructures consisting of complex guest-host monotiolated β-cyclodextrin host-iron), and a gold substrate. (Authors)

  13. Photoresponsive Molecular Recognition and Adhesion of Vesicles in a Competitive Ternary Supramolecular System

    NARCIS (Netherlands)

    Nalluri, Siva Krishna Mohan; Bultema, Jelle B.; Boekema, Egbert J.; Ravoo, Bart Jan

    A competitive photoresponsive supramolecular system is formed in a dilute aqueous solution of three components: vesicles of amphiphilic alpha-cyclodextrin host 1a, divalent p-methylphenyl guest 2 or divalent p-methylbenzamide guest 3, and photoresponsive azobenzene monovalent guest 5. Guests 2 and 3

  14. Understanding Periodic Dislocations in 2D Supramolecular Crystals: The PFP/Ag(111) Interface

    DEFF Research Database (Denmark)

    Goiri, E.; García Lastra, Juan Maria; Corso, M.

    2012-01-01

    In-plane dislocation networks arise in both inorganic and organic films as a way of relieving the elastic strain that builds up at the substrate interface. In molecule/surface systems, supramolecular interactions are weak and more complex (compared to the atomic bonds in inorganic films), and the...

  15. Linear Viscoelastic and Dielectric Relaxation Response of Unentangled UPy-Based Supramolecular Networks

    DEFF Research Database (Denmark)

    Shabbir, Aamir; Javakhishvili, Irakli; Cerveny, Silvina

    2016-01-01

    Supramolecular polymers possess versatile mechanical properties and a unique ability to respond to external stimuli. Understanding the rich dynamics of such associative polymers is essential for tailoring user-defined properties in many products. Linear copolymers of 2-methoxyethyl acrylate (MEA)...

  16. Growth anomalies in supramolecular networks: 4,4'-biphenyldicarboxylic acid on Cu(001)

    NARCIS (Netherlands)

    Schwarz, Daniel; van Gastel, Raoul; Zandvliet, Henricus J.W.; Poelsema, Bene

    2013-01-01

    We have used low energy electron microscopy to demonstrate how the interaction of 4,4 ′ -biphenyldicarboxylic acid (BDA) molecules with (steps on) the Cu(001) surface determines the structure of supramolecular BDA networks on a mesoscopic length scale. Our in situ real time observations reveal that

  17. Chiral Induction and amplification in supramolecular systems at the liquid-solid interface

    NARCIS (Netherlands)

    Xu, Hong; Ghijsens, E.; George, S.J.; Wolffs, M.; Tomovic, Z.; Schenning, A.P.H.J.; Feyter, de S.

    2013-01-01

    Chiral induction and amplification in surface-confined supramolecular monolayers are investigated at the liquid–solid interface. Scanning tunneling microscopy (STM) proves that achiral molecules can self-assemble into globally chiral patterns through a variety of approaches, including induction by

  18. Functional organic materials based on polymerized liquid-crystal monomers: supramolecular hydrogen-bonded systems

    NARCIS (Netherlands)

    Broer, D.J.; Bastiaansen, C.W.M.; Debije, M.G.; Schenning, A.P.H.J.

    2012-01-01

    Functional organic materials are of great interest for a variety of applications. To obtain precise functional properties, well-defined hierarchically ordered supramolecular materials are crucial. The self-assembly of liquid crystals has proven to be an extremely useful tool in the development of

  19. Minimalistic peptide supramolecular co-assembly: expanding the conformational space for nanotechnology.

    Science.gov (United States)

    Makam, Pandeeswar; Gazit, Ehud

    2018-05-21

    Molecular self-assembly is a ubiquitous process in nature and central to bottom-up nanotechnology. In particular, the organization of peptide building blocks into ordered supramolecular structures has gained much interest due to the unique properties of the products, including biocompatibility, chemical and structural diversity, robustness and ease of large-scale synthesis. In addition, peptides, as short as dipeptides, contain all the molecular information needed to spontaneously form well-ordered structures at both the nano- and the micro-scale. Therefore, peptide supramolecular assembly has been effectively utilized to produce novel materials with tailored properties for various applications in the fields of material science, engineering, medicine, and biology. To further expand the conformational space of peptide assemblies in terms of structural and functional complexity, multicomponent (two or more) peptide supramolecular co-assembly has recently evolved as a promising extended approach, similar to the structural diversity of natural sequence-defined biopolymers (proteins) as well as of synthetic covalent co-polymers. The use of this methodology was recently demonstrated in various applications, such as nanostructure physical dimension control, the creation of non-canonical complex topologies, mechanical strength modulation, the design of light harvesting soft materials, fabrication of electrically conducting devices, induced fluorescence, enzymatic catalysis and tissue engineering. In light of these significant advancements in the field of peptide supramolecular co-assembly in the last few years, in this tutorial review, we provide an updated overview and future prospects of this emerging subject.

  20. Amplification of chirality in helical supramolecular polymers: the majority-rules principle.

    NARCIS (Netherlands)

    Gestel, van J.A.M.

    2004-01-01

    Amplification of chirality, being a strongly nonlinear response of the optical activity of helical polymers to a small (net) amount of optically active material, has recently been discovered in supramolecular copolymers. Apart from the sergeants-and-soldiers type we discussed in earlier work,

  1. Understanding the molecular mechanisms involved in the interfacial self-healing of supramolecular rubbers

    NARCIS (Netherlands)

    Bose, R.K.; Garcia Espallargas, S.J.; Van der Zwaag, S.

    2013-01-01

    Supramolecular rubbers based on 2-aminoethylimidazolidone and fatty acids with epoxy crosslinks have been shown to self-heal via multiple hydrogen bonding sites. In this work, several tools are used to investigate the molecular mechanisms taking place at the interface to understand cohesive healing

  2. Terpyridine modified poly(vinyl chloride) : possibilities for supramolecular grafting and crosslinking

    NARCIS (Netherlands)

    Meier, M.A.R.; Schubert, U.S.

    2003-01-01

    Commercially available poly(vinyl chloride) (PVC) was covalently modified with terpyridine supramolecular binding units in a two-step reaction. First, PVC was modified with aromatic thiols to introduce OH functionalities into the polymer backbone, which were subsequently reacted with an

  3. Utilizing redox-chemistry to elucidate the nature of exciton transitions in supramolecular dye nanotubes

    NARCIS (Netherlands)

    Eisele, D. M.; Cone, C. W.; Bloemsma, E. A.; Vlaming, S. M.; van der Kwaak, C. G. F.; Silbey, R. J.; Bawendi, M. G.; Knoester, J.; Rabe, J. P.; Vanden Bout, D. A.

    Supramolecular assemblies that interact with light have recently garnered much interest as well-defined nanoscale materials for electronic excitation energy collection and transport. However, to control such complex systems it is essential to understand how their various parts interact and whether

  4. Drastic symmetry breaking in supramolecular organization of enantiomerically unbalanced monolayers at surfaces

    NARCIS (Netherlands)

    Haq, S.; Liu, N.; Humblot, V.; Jansen, A.P.J.; Raval, R.

    2009-01-01

    There is considerable interest in skewing the transmission of chirality, or 'handedness', from the molecular to the supramolecular level so that single-handed superstructures are created from mixed enantiomer systems. One approach is to flip the chirality of all the molecular building blocks to the

  5. Bio-inspired supramolecular materials by orthogonal self-assembly of hydrogelators and phospholipids

    NARCIS (Netherlands)

    Boekhoven, J.; Brizard, AMA; Stuart, M. C A; Florusse, L.J.; Raffy, G.; Del Guerzo, A.; van Esch, J.H.

    2016-01-01

    The orthogonal self-assembly of multiple components is a powerful strategy towards the formation of complex biomimetic architectures, but so far the rules for designing such systems are unclear. Here we show how to identify orthogonal self-assembly at the supramolecular level and describe

  6. Photoluminescence Spectra of Self-Assembling Helical Supramolecular Assemblies: A Theoretical Study

    NARCIS (Netherlands)

    van Dijk, Leon; Kersten, Sander P.; Jonkheijm, Pascal; van der Schoot, Paul; Bobbert, Peter A.

    2008-01-01

    The reversible assembly of helical supramolecular polymers of chiral molecular building blocks is known to be governed by the interplay between mass action and the competition between weakly and strongly bound states of these building blocks. The highly co-operative transition from free monomers at

  7. Cucurbit[8]uril templated supramolecular ring structure formation and protein assembly modulation

    NARCIS (Netherlands)

    Ramaekers, M.; Wijnands, S.P.W.; van Dongen, J.L.J.; Brunsveld, L.; Dankers, P.Y.W.

    2015-01-01

    The interplay of Phe-Gly-Gly (FGG)-tagged proteins and bivalent FGG-tagged penta(ethylene glycol) as guest molecules with cucurbit[8]uril (Q8) hosts is studied to modulate the supramolecular assembly process. Ring structure formation of the bivalent guest molecule with Q8 leads to enhanced binding

  8. The Supramolecular Organization of a Peptide-Based Nanocarrier at High Molecular Detail

    NARCIS (Netherlands)

    Rad-Malekshahi, Mazda; Visscher, Koen M.; Rodrigues, João P.G.L.M.; De Vries, Renko; Hennink, Wim E.; Baldus, Marc; Bonvin, Alexandre M.J.J.; Mastrobattista, Enrico; Weingarth, Markus

    2015-01-01

    Nanovesicles self-assembled from amphiphilic peptides are promising candidates for applications in drug delivery. However, complete high-resolution data on the local and supramolecular organization of such materials has been elusive thus far, which is a substantial obstacle to their rational design.

  9. Art, auto-mechanics, and supramolecular chemistry. A merging of hobbies and career.

    Science.gov (United States)

    Anslyn, Eric V

    2016-01-01

    While the strict definition of supramolecular chemistry is "chemistry beyond the molecule", meaning having a focus on non-covalent interactions, the field is primarily associated with the creation of synthetic receptors and self-assembly. For synthetic ease, the receptors and assemblies routinely possess a high degree of symmetry, which lends them an aspect of aesthetic beauty. Pictures of electron orbitals similarly can be seen as akin to works of art. This similarity was an early draw for me to the fields of supramolecular chemistry and molecular orbital theory, because I grew up in a household filled with art. In addition to art, my childhood was filled with repairing and constructing mechanical entities, such as internal combustion motors, where many components work together to achieve a function. Analogously, the field of supramolecular chemistry creates systems of high complexity that achieve functions or perform tasks. Therefore, in retrospect a career in supramolecular chemistry appears to be simply an extension of childhood hobbies involving art and auto-mechanics.

  10. Art, auto-mechanics, and supramolecular chemistry. A merging of hobbies and career

    Directory of Open Access Journals (Sweden)

    Eric V. Anslyn

    2016-02-01

    Full Text Available While the strict definition of supramolecular chemistry is “chemistry beyond the molecule”, meaning having a focus on non-covalent interactions, the field is primarily associated with the creation of synthetic receptors and self-assembly. For synthetic ease, the receptors and assemblies routinely possess a high degree of symmetry, which lends them an aspect of aesthetic beauty. Pictures of electron orbitals similarly can be seen as akin to works of art. This similarity was an early draw for me to the fields of supramolecular chemistry and molecular orbital theory, because I grew up in a household filled with art. In addition to art, my childhood was filled with repairing and constructing mechanical entities, such as internal combustion motors, where many components work together to achieve a function. Analogously, the field of supramolecular chemistry creates systems of high complexity that achieve functions or perform tasks. Therefore, in retrospect a career in supramolecular chemistry appears to be simply an extension of childhood hobbies involving art and auto-mechanics.

  11. Light Responsive Two-Component Supramolecular Hydrogel: A Sensitive Platform for Humidity Sensors

    KAUST Repository

    Samai, Suman

    2016-02-15

    The supramolecular assembly of anionic azobenzene dicarboxylate and cationic cetyltrimethylammonium bromide (CTAB) formed a stimuli responsive hydrogel with a critical gelation concentration (CGC) of 0.33 wt%. This self-sustainable two-component system was able to repair damage upon light irradiation. Moreover, it was successfully employed in the fabrication of highly sensitive humidity sensors for the first time.

  12. From metal-organic squares to porous zeolite-like supramolecular assemblies

    KAUST Repository

    Wang, Shuang

    2010-12-29

    We report the synthesis, structure, and characterization of two novel porous zeolite-like supramolecular assemblies, ZSA-1 and ZSA-2, having zeolite gis and rho topologies, respectively. The two compounds were assembled from functional metal-organic squares (MOSs) via directional hydrogen-bonding interactions and exhibited permanent microporosity and thermal stability up to 300 °C. © 2010 American Chemical Society.

  13. Supramolecular Layer-by-Layer Assembly of 3D Multicomponent Nanostructures via Multivalent Molecular Recognition

    NARCIS (Netherlands)

    Ling, X.Y.; Phang, In Yee; Reinhoudt, David; Vancso, Gyula J.; Huskens, Jurriaan

    2008-01-01

    The supramolecular layer-by-layer assembly of 3D multicomponent nanostructures of nanoparticles is demonstrated. Nanoimprint lithography (NIL) was used as the patterning tool for making patterned β-cyclodextrin (CD) self-assembled monolayers (SAMs) and for the confinement of nanoparticles on the

  14. Supramolecular organization and chiral resolution of p-terphenyl-m-dicarbonitrile on the Ag(111) surface.

    Science.gov (United States)

    Marschall, Matthias; Reichert, Joachim; Seufert, Knud; Auwärter, Willi; Klappenberger, Florian; Weber-Bargioni, Alexander; Klyatskaya, Svetlana; Zoppellaro, Giorgio; Nefedov, Alexei; Strunskus, Thomas; Wöll, Christof; Ruben, Mario; Barth, Johannes V

    2010-05-17

    The supramolecular organization and layer formation of the non-linear, prochiral molecule [1, 1';4',1'']-terphenyl-3,3"-dicarbonitrile adsorbed on the Ag(111) surface is investigated by scanning tunneling microscopy (STM) and near-edge X-ray absorption fine-structure spectroscopy (NEXAFS). Upon two-dimensional confinement the molecules are deconvoluted in three stereoisomers, that is, two mirror-symmetric trans- and one cis-species. STM measurements reveal large and regular islands following room temperature deposition, whereby NEXAFS confirms a flat adsorption geometry with the electronic pi-system parallel to the surface plane. The ordering within the expressed supramolecular arrays reflects a substrate templating effect, steric constraints and the operation of weak lateral interactions mainly originating from the carbonitrile endgroups. High-resolution data at room temperature reveal enantiormorphic characteristics of the molecular packing schemes in different domains of the arrays, indicative of chiral resolution during the 2D molecular self-assembly process. At submonolayer coverage supramolecular islands coexist with a disordered fluid phase of highly mobile molecules. Following thermal quenching (down to 6 K) we find extended supramolecular ribbons stabilised again by attractive and directional noncovalent interactions, the formation of which reflects a chiral resolution of trans-species.

  15. Macromolecules containing bipyridine and terpyridine metal complexes: towards metallo-supramolecular polymers

    NARCIS (Netherlands)

    Schubert, U.S.; Eschbaumer, C.

    2002-01-01

    The ability of a broad range of N-heterocycles to act as very effective and stable complexation agents for several transition metal ions, such as cobalt(II), copper(II), nickel(II), and ruthenium(II), has long been known in analytical chemistry. This behavior was later utilized in supramolecular

  16. Light Responsive Two-Component Supramolecular Hydrogel: A Sensitive Platform for Humidity Sensors

    KAUST Repository

    Samai, Suman; Sapsanis, Christos; Patil, Sachin; Ezzeddine, Alaa; Moosa, Basem; Omran, Hesham; Emwas, Abdul-Hamid M.; Salama, Khaled N.; Khashab, Niveen M.

    2016-01-01

    The supramolecular assembly of anionic azobenzene dicarboxylate and cationic cetyltrimethylammonium bromide (CTAB) formed a stimuli responsive hydrogel with a critical gelation concentration (CGC) of 0.33 wt%. This self-sustainable two-component system was able to repair damage upon light irradiation. Moreover, it was successfully employed in the fabrication of highly sensitive humidity sensors for the first time.

  17. On the kinetics of body versus end evaporation and addition of supramolecular polymers

    NARCIS (Netherlands)

    Tiwari, Nitin S.; van der Schoot, Paul

    2017-01-01

    Abstract.: The kinetics of the self-assembly of supramolecular polymers is dictated by how monomers, dimers, trimers etc., attach to and detach from each other. It is for this reasons that researchers have proposed a plethora of pathways to explain the kinetics of various self-assembling

  18. On the kinetics of body versus end evaporation and addition of supramolecular polymers

    NARCIS (Netherlands)

    Tiwari, N.; van der Schoot, P.P.A.M.

    2017-01-01

    The kinetics of the self-assembly of supramolecular polymers is dictated by how monomers, dimers, trimers etc., attach to and detach from each other. It is for this reasons that researchers have proposed a plethora of pathways to explain the kinetics of various self-assembling supramolecules,

  19. Painting Supramolecular Polymers in Organic Solvents by Super-resolution Microscopy

    Science.gov (United States)

    2018-01-01

    Despite the rapid development of complex functional supramolecular systems, visualization of these architectures under native conditions at high resolution has remained a challenging endeavor. Super-resolution microscopy was recently proposed as an effective tool to unveil one-dimensional nanoscale structures in aqueous media upon chemical functionalization with suitable fluorescent probes. Building upon our previous work, which enabled photoactivation localization microscopy in organic solvents, herein, we present the imaging of one-dimensional supramolecular polymers in their native environment by interface point accumulation for imaging in nanoscale topography (iPAINT). The noncovalent staining, typical of iPAINT, allows the investigation of supramolecular polymers’ structure in situ without any chemical modification. The quasi-permanent adsorption of the dye to the polymer is exploited to identify block-like arrangements within supramolecular fibers, which were obtained upon mixing homopolymers that were prestained with different colors. The staining of the blocks, maintained by the lack of exchange of the dyes, permits the imaging of complex structures for multiple days. This study showcases the potential of PAINT-like strategies such as iPAINT to visualize multicomponent dynamic systems in their native environment with an easy, synthesis-free approach and high spatial resolution. PMID:29697958

  20. Research in the Laboratory of Supramolecular Chemistry: functional nanostructures, sensors, and catalysts.

    Science.gov (United States)

    Severin, Kay

    2011-01-01

    This article summarizes research activities in the Laboratory of Supramolecular Chemistry (LCS) at the EPFL. Three topics will be discussed: a) the construction of functional nanostructures by multicomponent self-assembly processes, b) the development of chemosensors using specific receptors or ensembles of crossreactive sensors, and c) the investigation of novel synthetic procedures with organometallic catalysts.

  1. Supramolecular binding and release of sulfide and hydrosulfide anions in water.

    Science.gov (United States)

    Vázquez, J; Sindelar, V

    2018-06-05

    Hydrogen sulfide (H2S) has become an important target for research due to its physiological properties as well as its potential applications in medicine. In this work, supramolecular binding of sulfide (S2-) and hydrosulfide (HS-) anions in water is presented for the first time. Bambusurils were used to slow down the release of these anions in water.

  2. Diverse Supramolecular Nanofiber Networks Assembled by Functional Low-Complexity Domains.

    Science.gov (United States)

    An, Bolin; Wang, Xinyu; Cui, Mengkui; Gui, Xinrui; Mao, Xiuhai; Liu, Yan; Li, Ke; Chu, Cenfeng; Pu, Jiahua; Ren, Susu; Wang, Yanyi; Zhong, Guisheng; Lu, Timothy K; Liu, Cong; Zhong, Chao

    2017-07-25

    Self-assembling supramolecular nanofibers, common in the natural world, are of fundamental interest and technical importance to both nanotechnology and materials science. Despite important advances, synthetic nanofibers still lack the structural and functional diversity of biological molecules, and the controlled assembly of one type of molecule into a variety of fibrous structures with wide-ranging functional attributes remains challenging. Here, we harness the low-complexity (LC) sequence domain of fused in sarcoma (FUS) protein, an essential cellular nuclear protein with slow kinetics of amyloid fiber assembly, to construct random copolymer-like, multiblock, and self-sorted supramolecular fibrous networks with distinct structural features and fluorescent functionalities. We demonstrate the utilities of these networks in the templated, spatially controlled assembly of ligand-decorated gold nanoparticles, quantum dots, nanorods, DNA origami, and hybrid structures. Owing to the distinguishable nanoarchitectures of these nanofibers, this assembly is structure-dependent. By coupling a modular genetic strategy with kinetically controlled complex supramolecular self-assembly, we demonstrate that a single type of protein molecule can be used to engineer diverse one-dimensional supramolecular nanostructures with distinct functionalities.

  3. Synthesis and characterization of metallo-supramolecular polymers from thiophene-based unimers bearing pybox ligands

    Czech Academy of Sciences Publication Activity Database

    Hladysh, S.; Václavková, D.; Vrbata, D.; Bondarev, D.; Havlíček, D.; Svoboda, Jan; Zedník, J.; Vohlídal, J.

    2017-01-01

    Roč. 7, č. 18 (2017), s. 10718-10728 ISSN 2046-2069 Institutional support: RVO:61389013 Keywords : metallo-supramolecular polymers * XPS Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer science Impact factor: 3.108, year: 2016

  4. Synthesis and Characterization of Calixarene Tetraethers: An Exercise in Supramolecular Chemistry for the Undergraduate Organic Laboratory

    Science.gov (United States)

    Debbert, Stefan L.; Hoh, Bradley D.; Dulak, David J.

    2016-01-01

    In this experiment for an introductory undergraduate organic chemistry lab, students tetraalkylate tertbutylcalix[4]arene, a bowl-shaped macrocyclic oligophenol, and examine the supramolecular chemistry of the tetraether product by proton nuclear magnetic resonance (NMR) spectroscopy. Complexation with a sodium ion reduces the conformational…

  5. Injectable self-healing carboxymethyl chitosan-zinc supramolecular hydrogels and their antibacterial activity.

    Science.gov (United States)

    Wahid, Fazli; Zhou, Ya-Ning; Wang, Hai-Song; Wan, Tong; Zhong, Cheng; Chu, Li-Qiang

    2018-04-07

    Injectable and self-healing hydrogels have found numerous applications in drug delivery, tissue engineering and 3D cell culture. Herein, we report an injectable self-healing carboxymethyl chitosan (CMCh) supramolecular hydrogels cross-linked by zinc ions (Zn 2+ ). Supramolecular hydrogels were obtained by simple addition of metal ions solution to CMCh solution at an appropriate pH value. The mechanical properties of these hydrogels were adjustable by the concentration of Zn 2+ . For example, the hydrogel with the highest concentration of Zn 2+ (CMCh-Zn4) showed strongest mechanical properties (storage modulus~11,000Pa) while hydrogel with the lowest concentration of Zn 2+ (CMCh-Zn1) showed weakest mechanical properties (storage modulus~220Pa). As observed visually and confirmed rheologically, the CMCh-Zn1 hydrogel with the lowest Zn 2+ concentration showed thixotropic property. CMCh-Zn1 hydrogel also presented injectable property. Moreover, the antibacterial properties of the prepared supramolecular hydrogels were studied against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) by agar well diffusion method. The results revealed Zn 2+ dependent antibacterial properties against both kinds of strains. The inhibition zones were ranging from ~11-24mm and ~10-22mm against S. aureus and E. coli, respectively. We believe that the prepared supramolecular hydrogels could be used as a potential candidate in biomedical fields. Copyright © 2018 Elsevier B.V. All rights reserved.

  6. Self-assembling multivalency : supramolecular polymers assembled from monovalent mannose-labelled discotic molecules

    NARCIS (Netherlands)

    Petkau - Milroy, K.; Brunsveld, L.

    2013-01-01

    Supramolecular synthesis, the "bottom-up" construction of higher-order structures from monomeric building blocks, represents a flexible approach for the generation of multivalent materials. Here, monovalent building blocks decorated with a single bioactive ligand were synthesized. In water, these

  7. Influence of the preparation route on the supramolecular organization of lipids in a vesicular system

    DEFF Research Database (Denmark)

    Elizondo, Elisa; Larsen, Jannik; Hatzakis, Nikos

    2012-01-01

    A confocal fluorescence microscopy-based assay was used for studying the influence of the preparation route on the supramolecular organization of lipids in a vesicular system. In this work, vesicles composed of cholesterol and CTAB (1/1 mol %) or cholesterol and DOPC (2/8 mol %) and incorporating...

  8. Facile preparation of luminescent and intelligent gold nanodots based on supramolecular self-assembly

    International Nuclear Information System (INIS)

    Shi Yunfeng; Li Sujuan; Zhou Yahui; Zhai Qingpan; Hu Mengyue; Cai Fensha; Du Jimin; Liang Jiamiao; Zhu Xinyuan

    2012-01-01

    A new strategy for preparing luminescent and intelligent gold nanodots based on supramolecular self-assembly is described in this paper. The supramolecular self-assembly was initiated through electrostatic interactions and ion pairing between palmitic acid and hyperbranched poly(ethylenimine). The resulting structures not only have the dynamic reversible properties of supramolecules but also possess torispherical and highly branched architectures. Thus they can be regarded as a new kind of ideal nanoreactor for preparing intelligent Au nanodots. By preparing Au nanodots within this kind of supramolecular self-assembly, the environmental sensitivity of intelligent polymers and the optical, electrical properties of Au nanodots can be combined, endowing the Au nanodots with intelligence. In this paper, a supramolecular self-assembly process based on dendritic poly(ethylenimine) and palmitic acid was designed and then applied to prepare fluorescent and size-controlled Au nanodots. The pH response of Au nanodots embodied by phase transfer from oil phase to water phase was also investigated. (paper)

  9. Preparation of supramolecular hydrogel-enzyme hybrids exhibiting biomolecule-responsive gel degradation.

    Science.gov (United States)

    Shigemitsu, Hajime; Fujisaku, Takahiro; Onogi, Shoji; Yoshii, Tatsuyuki; Ikeda, Masato; Hamachi, Itaru

    2016-09-01

    Hydrogelators are small, self-assembling molecules that form supramolecular nanofiber networks that exhibit unique dynamic properties. Development of supramolecular hydrogels that degrade in response to various biomolecules could potentially be used for applications in areas such as drug delivery and diagnostics. Here we provide a synthetic procedure for preparing redox-responsive supramolecular hydrogelators that are used to create hydrogels that degrade in response to oxidizing or reducing conditions. The synthesis takes ∼2-4 d, and it can potentially be carried out in parallel to prepare multiple hydrogelator candidates. This described solid-phase peptide synthesis protocol can be used to produce previously described hydrogelators or to construct a focused molecular library to efficiently discover and optimize new hydrogelators. In addition, we describe the preparation of redox-responsive supramolecular hydrogel-enzyme hybrids that are created by mixing aqueous solutions of hydrogelators and enzymes, which requires 2 h for completion. The resultant supramolecular hydrogel-enzyme hybrids exhibit gel degradation in response to various biomolecules, and can be rationally designed by connecting the chemical reactions of the hydrogelators with enzymatic reactions. Gel degradation in response to biomolecules as triggers occurs within a few hours. We also describe the preparation of hydrogel-enzyme hybrids arrayed on flat glass slides, enabling high-throughput analysis of biomolecules such as glucose, uric acid, lactate and so on by gel degradation, which is detectable by the naked eye. The protocol requires ∼6 h to prepare the hydrogel-enzyme hybrid array and to complete the biomolecule assay.

  10. Chiral Binaphthylbis(4,4'-Bipyridin-1-Ium)/Cucurbit[8]Uril Supramolecular System and Its Induced Circularly Polarized Luminescence.

    Science.gov (United States)

    Chen, Xu-Man; Chen, Yong; Liang, Lu; Liu, Qiu-Jun; Liu, Yu

    2018-05-01

    Circularly polarized luminescence (CPL) induced by host-guest complexation remains a challenge in supramolecular chemistry. Herein, a couple of CPL-silent enantiomeric guest binaphthylbis(4,4'-bipyridinium) salts can emit obvious CPL in the presence of cucurbit[8]uril in aqueous media, due to the restriction of molecular rotation limitation effect. Such CPL can be reversibly adjusted by the addition of acid and base. Furthermore, the resultant supramolecular systems can interact with DNA, accompanied by the morphological conversion from branched supramolecular nanowires to exfoliated nanowires, which can enable to the exploration of such supramolecular systems as DNA markers by CPL signals. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Rational design of single-molecule magnets: a supramolecular approach.

    Science.gov (United States)

    Glaser, Thorsten

    2011-01-07

    )Cr(III)](3+), [Mn(III)(6)Fe(III)](3+), and [Mn(III)(6)Co(III)](3+) with [Mn(III)(6)Cr(III)](3+) being a SMM. A detailed analysis and comparison of the magnetic properties of the three heptanuclear complexes and the tetranuclear half-unit [Mn(III)(3)Cr(III)](3+) provides significant insight for further optimization of the SMM properties. The modular assembly of the heptanuclear complexes from three molecular building blocks allows the fine-tuning of the molecular and steric properties of each building block without losing the driving force for the formation of the heptanuclear complexes. This possibility of rational improvements of our isostructural series is the main advantage of our supramolecular approach.

  12. Supramolecular Nanostructures Based on Cyclodextrin and Poly(ethylene oxide: Syntheses, Structural Characterizations and Applications for Drug Delivery

    Directory of Open Access Journals (Sweden)

    Yue Zheng

    2016-05-01

    Full Text Available Cyclodextrins (CDs have been extensively studied as drug delivery carriers through host–guest interactions. CD-based poly(pseudorotaxanes, which are composed of one or more CD rings threading on the polymer chain with or without bulky groups (or stoppers, have attracted great interest in the development of supramolecular biomaterials. Poly(ethylene oxide (PEO is a water-soluble, biocompatible polymer. Depending on the molecular weight, PEO can be used as a plasticizer or as a toughening agent. Moreover, the hydrogels of PEO are also extensively studied because of their outstanding characteristics in biological drug delivery systems. These biomaterials based on CD and PEO for controlled drug delivery have received increasing attention in recent years. In this review, we summarize the recent progress in supramolecular architectures, focusing on poly(pseudorotaxanes, vesicles and supramolecular hydrogels based on CDs and PEO for drug delivery. Particular focus will be devoted to the structures and properties of supramolecular copolymers based on these materials as well as their use for the design and synthesis of supramolecular hydrogels. Moreover, the various applications of drug delivery techniques such as drug absorption, controlled release and drug targeting based CD/PEO supramolecular complexes, are also discussed.

  13. Fabrication of Supramolecular Chirality from Achiral Molecules at the Liquid/Liquid Interface Studied by Second Harmonic Generation.

    Science.gov (United States)

    Lin, Lu; Zhang, Zhen; Guo, Yuan; Liu, Minghua

    2018-01-09

    We present the investigation into the supramolecular chirality of 5-octadecyloxy-2-(2-pyridylazo)phenol (PARC18) at water/1,2-dichloroethane interface by second harmonic generation (SHG). We observe that PARC18 molecules form supramolecular chirality through self-assembly at the liquid/liquid interface although they are achiral molecules. The bulk concentration of PARC18 in the organic phase has profound effects on the supramolecular chirality. By increasing bulk concentration, the enantiomeric excess at the interface first grows and then decreases until it eventually vanishes. Further analysis reveals that the enantiomeric excess is determined by the twist angle of PARC18 molecules at the interface rather than their orientational angle. At lower and higher bulk concentrations, the average twist angle of PARC18 molecules approaches zero, and the assemblies are achiral; whereas at medium bulk concentrations, the average twist angle is nonzero, so that the assemblies show supramolecular chirality. We also estimate the coverage of PARC18 molecules at the interface versus the bulk concentration and fit it to Langmuir adsorption model. The result indicates that PARC18 assemblies show strongest supramolecular chirality in a half-full monolayer. These findings highlight the opportunities for precise control of supramolecular chirality at liquid/liquid interfaces by manipulating the bulk concentration.

  14. Reversible Self-Assembly of Supramolecular Vesicles and Nanofibers Driven by Chalcogen-Bonding Interactions.

    Science.gov (United States)

    Chen, Liang; Xiang, Jun; Zhao, Yue; Yan, Qiang

    2018-05-29

    Chalcogen-bonding interactions have been viewed as new noncovalent forces in supramolecular chemistry. However, harnessing chalcogen bonds to drive molecular self-assembly processes is still unexplored. Here we report for the first time a novel class of supra-amphiphiles formed by Te···O or Se···O chalcogen-bonding interactions, and their self-assembly into supramolecular vesicles and nanofibers. A quasi-calix[4]chalcogenadiazole (C4Ch) as macrocyclic donor and a tailed pyridine N-oxide surfactant as molecular acceptor are designed to construct the donor-acceptor complex via chalcogen-chalcogen connection between the chalcogenadiazole moieties and oxide anion. The affinity of such chalcogen-bonding can dictate the geometry of supra-amphiphiles, driving diverse self-assembled morphologies. Furthermore, the reversible disassembly of these nanostructures can be promoted by introducing competing anions, such as halide ions, or by decreasing the systemic pH value.

  15. A supramolecular miktoarm star polymer based on porphyrin metal complexation in water.

    Science.gov (United States)

    Hou, Zhanyao; Dehaen, Wim; Lyskawa, Joël; Woisel, Patrice; Hoogenboom, Richard

    2017-07-25

    A novel supramolecular miktoarm star polymer was successfully constructed in water from a pyridine end-decorated polymer (Py-PmDEGA) and a metalloporphyrin based star polymer (ZnTPP-(PEG) 4 ) via metal-ligand coordination. The Py-PmDEGA moiety was prepared via a combination of reversible addition-fragmentation chain transfer polymerization (RAFT) and subsequent aminolysis and Michael addition reactions to introduce the pyridine end-group. The ZnTPP(PEG) 4 star-polymer was synthesized by the reaction between tetrakis(p-hydroxyphenyl)porphyrin and toluenesulfonyl-PEG, followed by insertion of a zinc ion into the porphyrin core. The formation of a well-defined supramolecular AB 4 -type miktoarm star polymer was unambiguously demonstrated via UV-Vis spectroscopic titration, isothermal titration calorimetry (ITC) and diffusion ordered NMR spectroscopy (DOSY).

  16. Supramolecular effects as driving force of dipyrrin based functional materials engineering

    Science.gov (United States)

    Banakova, E.; Bobrov, A.; Kazak, A.; Marfin, Yu; Merkushev, D.; Molchanov, E.; Rumyantsev, E.; Shipalova, M.; Usoltsev, S.; Vodyanova, O.

    2018-01-01

    Dipyrrin based luminophores are of major interest in different areas of chemistry, material science and molecular biology. Vast variety of the structures with dipyrrin motif were synthesized and investigated up to date. Modern trend in the dipyrrin chemistry is the aimed functionalization of the ligand or complex structure allowing to gain the mechanism based on supramolecular interactions for controlling spectral and photophysical characteristics of compounds for tuning practically valuable properties for specific tasks. Presented paper summarize the results of our research group, working in the field of dipyrrin complexes with p-elements: synthesis, spectral characteristics evaluation and possibilities of practical application investigation. Discussion is focused on the opportunities of molecules preorganization for achieving the supramolecular interactions causing the tuning of fluorescence of the compounds in solutions, polymeric matrices and thin films.

  17. Macromolecularly crowded in vitro microenvironments accelerate the production of extracellular matrix-rich supramolecular assemblies.

    Science.gov (United States)

    Kumar, Pramod; Satyam, Abhigyan; Fan, Xingliang; Collin, Estelle; Rochev, Yury; Rodriguez, Brian J; Gorelov, Alexander; Dillon, Simon; Joshi, Lokesh; Raghunath, Michael; Pandit, Abhay; Zeugolis, Dimitrios I

    2015-03-04

    Therapeutic strategies based on the principles of tissue engineering by self-assembly put forward the notion that functional regeneration can be achieved by utilising the inherent capacity of cells to create highly sophisticated supramolecular assemblies. However, in dilute ex vivo microenvironments, prolonged culture time is required to develop an extracellular matrix-rich implantable device. Herein, we assessed the influence of macromolecular crowding, a biophysical phenomenon that regulates intra- and extra-cellular activities in multicellular organisms, in human corneal fibroblast culture. In the presence of macromolecules, abundant extracellular matrix deposition was evidenced as fast as 48 h in culture, even at low serum concentration. Temperature responsive copolymers allowed the detachment of dense and cohesive supramolecularly assembled living substitutes within 6 days in culture. Morphological, histological, gene and protein analysis assays demonstrated maintenance of tissue-specific function. Macromolecular crowding opens new avenues for a more rational design in engineering of clinically relevant tissue modules in vitro.

  18. Rapid fabrication of hierarchically structured supramolecular nanocomposite thin films in one minute

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Ting; Kao, Joseph

    2016-11-08

    Functional nanocomposites containing nanoparticles of different chemical compositions may exhibit new properties to meet demands for advanced technology. It is imperative to simultaneously achieve hierarchical structural control and to develop rapid, scalable fabrication to minimize degradation of nanoparticle properties and for compatibility with nanomanufacturing. The assembly kinetics of supramolecular nanocomposite in thin films is governed by the energetic cost arising from defects, the chain mobility, and the activation energy for inter-domain diffusion. By optimizing only one parameter, the solvent fraction in the film, the assembly kinetics can be precisely tailored to produce hierarchically structured thin films of supramolecular nanocomposites in approximately one minute. Moreover, the strong wavelength dependent optical anisotropy in the nanocomposite highlights their potential applications for light manipulation and information transmission. The present invention opens a new avenue in designing manufacture-friendly continuous processing for the fabrication of functional nanocomposite thin films.

  19. Supramolecular Complexation of Carbohydrates for the Bioavailability Enhancement of Poorly Soluble Drugs.

    Science.gov (United States)

    Cho, Eunae; Jung, Seunho

    2015-10-27

    In this review, a comprehensive overview of advances in the supramolecular complexes of carbohydrates and poorly soluble drugs is presented. Through the complexation process, poorly soluble drugs could be efficiently delivered to their desired destinations. Carbohydrates, the most abundant biomolecules, have diverse physicochemical properties owing to their inherent three-dimensional structures, hydrogen bonding, and molecular recognition abilities. In this regard, oligosaccharides and their derivatives have been utilized for the bioavailability enhancement of hydrophobic drugs via increasing the solubility or stability. By extension, polysaccharides and their derivatives can form self-assembled architectures with poorly soluble drugs and have shown increased bioavailability in terms of the sustained or controlled drug release. These supramolecular systems using carbohydrate will be developed consistently in the field of pharmaceutical and medical application.

  20. Metal-Ion-Mediated Supramolecular Chirality of l-Phenylalanine Based Hydrogels.

    Science.gov (United States)

    Wang, Fang; Feng, Chuan-Liang

    2018-05-14

    For chiral hydrogels and related applications, one of the critical issues is how to control the chirality of supramolecular systems in an efficient way, including easy operation, efficient transfer of chirality, and so on. Herein, supramolecular chirality of l-phenylalanine based hydrogels can be effectively controlled by using a broad range of metal ions. The degree of twisting (twist pitch) and the diameter of the chiral nanostructures can also be efficiently regulated. These are ascribed to the synergic effect of hydrogen bonding and metal ion coordination. This study may develop a method to design a new class of electronically, optically, and biologically active materials. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Solvent polarity effects on supramolecular chirality of a polyfluorene-thiophene copolymer.

    Science.gov (United States)

    Hirahara, Takashi; Yoshizawa-Fujita, Masahiro; Takeoka, Yuko; Rikukawa, Masahiro

    2018-06-01

    This study demonstrates the supramolecular chirality control of a conjugated polymer via solvent polarity. We designed and synthesized a chiral polyfluorene-thiophene copolymer having two different chiral side chains at the 9-position of the fluorene unit. Chiral cyclic and alkyl ethers with different polarities were selected as the chiral side chains. The sign of the circular dichroism spectra in the visible wavelength region was affected by the solvent system, resulting from the change of supramolecular structure. The estimation of the solubility parameter revealed that the solubility difference of the side chains contributed to the change of the circular dichroism sign, which was also observed in spin-coated films prepared from good solvents having different polarities. © 2018 Wiley Periodicals, Inc.

  2. Revealing the Supramolecular Nature of Side-Chain Terpyridine-Functionalized Polymer Networks

    Directory of Open Access Journals (Sweden)

    Jérémy Brassinne

    2015-01-01

    Full Text Available Nowadays, finely controlling the mechanical properties of polymeric materials is possible by incorporating supramolecular motifs into their architecture. In this context, the synthesis of a side-chain terpyridine-functionalized poly(2-(dimethylaminoethyl methacrylate is reported via reversible addition-fragmentation chain transfer polymerization. By addition of transition metal ions, concentrated aqueous solutions of this polymer turn into metallo-supramolecular hydrogels whose dynamic mechanical properties are investigated by rotational rheometry. Hence, the possibility for the material to relax mechanical constrains via dissociation of transient cross-links is brought into light. In addition, the complex phenomena occurring under large oscillatory shear are interpreted in the context of transient networks.

  3. Noncovalent assembly. A rational strategy for the realization of chain-growth supramolecular polymerization.

    Science.gov (United States)

    Kang, Jiheong; Miyajima, Daigo; Mori, Tadashi; Inoue, Yoshihisa; Itoh, Yoshimitsu; Aida, Takuzo

    2015-02-06

    Over the past decade, major progress in supramolecular polymerization has had a substantial effect on the design of functional soft materials. However, despite recent advances, most studies are still based on a preconceived notion that supramolecular polymerization follows a step-growth mechanism, which precludes control over chain length, sequence, and stereochemical structure. Here we report the realization of chain-growth polymerization by designing metastable monomers with a shape-promoted intramolecular hydrogen-bonding network. The monomers are conformationally restricted from spontaneous polymerization at ambient temperatures but begin to polymerize with characteristics typical of a living mechanism upon mixing with tailored initiators. The chain growth occurs stereoselectively and therefore enables optical resolution of a racemic monomer. Copyright © 2015, American Association for the Advancement of Science.

  4. Chiral supramolecular organization from a sheet-like achiral gel: a study of chiral photoinduction.

    Science.gov (United States)

    Royes, Jorge; Polo, Víctor; Uriel, Santiago; Oriol, Luis; Piñol, Milagros; Tejedor, Rosa M

    2017-05-31

    Chiral photoinduction in a photoresponsive gel based on an achiral 2D architecture with high geometric anisotropy and low roughness has been investigated. Circularly polarized light (CPL) was used as a chiral source and an azobenzene chromophore was employed as a chiral trigger. The chiral photoinduction was studied by evaluating the preferential excitation of enantiomeric conformers of the azobenzene units. Crystallographic data and density functional theory (DFT) calculations show how chirality is transferred to the achiral azomaterials as a result of the combination of chiral photochemistry and supramolecular interactions. This procedure could be applied to predict and estimate chirality transfer from a chiral physical source to a supramolecular organization using different light-responsive units.

  5. Synthesis and characterization of maltose-based amphiphiles as supramolecular hydrogelators.

    Science.gov (United States)

    Clemente, María J; Fitremann, Juliette; Mauzac, Monique; Serrano, José L; Oriol, Luis

    2011-12-20

    Low molecular mass amphiphilic glycolipids have been prepared by linking a maltose polar head and a hydrophobic linear chain either by amidation or copper(I)-catalyzed azide-alkyne [3 + 2] cycloaddition. The liquid crystalline properties of these amphiphilic materials have been characterized. The influence of the chemical structure of these glycolipids on the gelation properties in water has also been studied. Glycolipids obtained by the click coupling of the two components give rise to stable hydrogels at room temperature. The fibrillar structure of supramolecular hydrogels obtained by the self-assembly of these gelators have been characterized by electron microscopy. Fibers showed some torsion, which could be related with a chiral supramolecular arrangement of amphiphiles, as confirmed by circular dichroism (CD). The sol-gel transition temperature was also determined by differential scanning calorimetry (DSC) and NMR. © 2011 American Chemical Society

  6. Methodology for studying molecular and supramolecular structures of coals and carbonaceous materials

    Energy Technology Data Exchange (ETDEWEB)

    G.B. Skripchenko [Russian Academy of Sciences, Moscow (Russian Federation). Russia Institute for Fossil Fuels - Science and Technology Center for Complex Processing of Solid Fossil Fuels

    2009-07-01

    Those studying coals have to account for petrographic nonuniformity (the optical structural level), different types of chemical bonding between structural fragments, the existence of aromatic clusters in the organic matter, the appearance of a supramolecular order between aromatic clusters, and further orientation ordering of crystallites under the action of the geological pressure. Combinations of conventional chemical strategies with advanced physicochemical methods, such as IR, NMR, EPR, and X-ray spectroscopy; X-ray diffraction; electronic and scanning microscopy; and some others, are pertinent for structure determination. The appearance of supramolecular structures is a manifestation of molecular-level structural rearrangements, which are characteristic of coals, cokes, pitches, and various pyrolytic carbons. This necessitates the use of optical, electronic, and scanning microscopy along with other chemical methods. The occurrence of mineral components in coals can appreciably limit the resolution of IR spectroscopy and X-ray crystallography.

  7. Supramolecular structure of a perylene derivative in thin films deposited by physical vapor deposition

    International Nuclear Information System (INIS)

    Fernandes, Jose D.; Aoki, Pedro H.B.; Constantino, Carlos J.J.; Junior, Wagner D.M.; Teixeira, Silvio R.

    2014-01-01

    Full text: Thin films of a perylene derivative, the bis butylimido perylene (BuPTCD), were produced using thermal evaporation (PVD, physical vapor deposition). The main objective is to investigate the supramolecular structure of the BuPTCD in these PVD films, which implies to control the thickness and to determine the molecular organization, morphology at micro and nanometer scales and crystallinity. This supramolecular structure is a key factor in the optical and electrical properties of the film. The ultraviolet-visible absorption revealed an uniform growth of the PVD films. The optical and atomic force microscopy images showed a homogeneous surface of the film at micro and nanometer scales. A preferential orientation of the molecules in the PVD films was determined via infrared absorption. The X-ray diffraction showed that both powder and PVD film are in the crystalline form. (author)

  8. Supramolecular structure of jackfruit seed starch and its relationship with digestibility and physicochemical properties.

    Science.gov (United States)

    Chen, Jin; Liang, Yi; Li, Xiaoxi; Chen, Ling; Xie, Fengwei

    2016-10-05

    The influence of supramolecular structure on the physicochemical properties and digestibility of jackfruit seed starch (JSS) were investigated. Compared with maize and cassava starches (MS and CS), JSS had smaller granules and higher amylose content (JSS: 24.90%; CS: 16.68%; and MS: 22.42%), which contributed to higher gelatinization temperature (To: 81.11°C) and setback viscosity (548.9mPas). From scanning electron microscopy, the digestion of JSS was observed mainly at the granule surface. Due to its higher crystallinity (JSS: 30.6%; CS: 30.3%; and MS: 27.4%) and more ordered semi-crystalline lamellae, JSS had a high RS content (74.26%) and melting enthalpy (19.61J/g). In other words, the supramolecular structure of JSS extensively determined its digestibility and resistance to heat and mechanical shear treatment. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Self-assembly of cationic multidomain peptide hydrogels: supramolecular nanostructure and rheological properties dictate antimicrobial activity

    Science.gov (United States)

    Jiang, Linhai; Xu, Dawei; Sellati, Timothy J.; Dong, He

    2015-11-01

    Hydrogels are an important class of biomaterials that have been widely utilized for a variety of biomedical/medical applications. The biological performance of hydrogels, particularly those used as wound dressing could be greatly advanced if imbued with inherent antimicrobial activity capable of staving off colonization of the wound site by opportunistic bacterial pathogens. Possessing such antimicrobial properties would also protect the hydrogel itself from being adversely affected by microbial attachment to its surface. We have previously demonstrated the broad-spectrum antimicrobial activity of supramolecular assemblies of cationic multi-domain peptides (MDPs) in solution. Here, we extend the 1-D soluble supramolecular assembly to 3-D hydrogels to investigate the effect of the supramolecular nanostructure and its rheological properties on the antimicrobial activity of self-assembled hydrogels. Among designed MDPs, the bactericidal activity of peptide hydrogels was found to follow an opposite trend to that in solution. Improved antimicrobial activity of self-assembled peptide hydrogels is dictated by the combined effect of supramolecular surface chemistry and storage modulus of the bulk materials, rather than the ability of individual peptides/peptide assemblies to penetrate bacterial cell membrane as observed in solution. The structure-property-activity relationship developed through this study will provide important guidelines for designing biocompatible peptide hydrogels with built-in antimicrobial activity for various biomedical applications.Hydrogels are an important class of biomaterials that have been widely utilized for a variety of biomedical/medical applications. The biological performance of hydrogels, particularly those used as wound dressing could be greatly advanced if imbued with inherent antimicrobial activity capable of staving off colonization of the wound site by opportunistic bacterial pathogens. Possessing such antimicrobial properties would

  10. Integration of molecular machines into supramolecular materials: actuation between equilibrium polymers and crystal-like gels.

    Science.gov (United States)

    Mariani, Giacomo; Goujon, Antoine; Moulin, Emilie; Rawiso, Michel; Giuseppone, Nicolas; Buhler, Eric

    2017-11-30

    In this article, the dynamic structure of complex supramolecular polymers composed of bistable [c2]daisy chain rotaxanes as molecular machines that are linked by ureidopyrimidinones (Upy) as recognition moieties was studied. pH actuation of the integrated mechanically active rotaxanes controls the contraction/extension of the polymer chains as well as their physical reticulation. Small-angle neutron and X-ray scattering were used to study in-depth the nanostructure of the contracted and extended polymer aggregates in toluene solution. The supramolecular polymers comprising contracted nanomachines were found to be equilibrium polymers with a mass that is concentration dependent in dilute and semidilute regimes. Surprisingly, the extended polymers form a gel network with a crystal-like internal structure that is independent of concentration and reminiscent of a pearl-necklace network.

  11. Computation-Guided Design of a Stimulus-Responsive Multienzyme Supramolecular Assembly.

    Science.gov (United States)

    Yang, Lu; Dolan, Elliott M; Tan, Sophia K; Lin, Tianyun; Sontag, Eduardo D; Khare, Sagar D

    2017-10-18

    The construction of stimulus-responsive supramolecular complexes of metabolic pathway enzymes, inspired by natural multienzyme assemblies (metabolons), provides an attractive avenue for efficient and spatiotemporally controllable one-pot biotransformations. We have constructed a phosphorylation- and optically responsive metabolon for the biodegradation of the environmental pollutant 1,2,3-trichloropropane. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Carborane-beta-cyclodextrin complexes as a supramolecular connector for bioactive surfaces

    Czech Academy of Sciences Publication Activity Database

    Neirynck, P.; Schimer, Jiří; Jonkheijm, P.; Milroy, L. G.; Cígler, Petr; Brunsveld, L.

    2015-01-01

    Roč. 3, č. 4 (2015), s. 539-545 ISSN 2050-750X R&D Projects: GA MŠk(CZ) LH11027 Institutional support: RVO:61388963 Keywords : beta-cyclodextrine/carborane host-guest system * supramolecular chemistry * bioactive surfaces Subject RIV: CD - Macromolecular Chemistry Impact factor: 4.872, year: 2015 http://pubs.rsc.org/en/content/articlepdf/2015/tb/c4tb01489h

  13. Photoactive assemblies of organic compounds and biomolecules: drug-protein supramolecular systems

    OpenAIRE

    Vayá Pérez, Ignacio; Lhiaubet-Vallet, Virginie Lyria; Jiménez Molero, María Consuelo; Miranda Alonso, Miguel Ángel

    2014-01-01

    [EN] The properties of singlet and triplet excited states are strongly medium-dependent. Hence, these species constitute valuable tools as reporters to probe compartmentalised microenvironments, including drug@protein supramolecular systems. In the present review, the attention is focused on the photophysical properties of the probe drugs (rather than those of the protein chromophores) using transport proteins (serum albumins and 1-acid glycoproteins) as hosts. Specifically, f...

  14. Activation of ice recrystallization inhibition activity of poly(vinyl alcohol) using a supramolecular trigger

    OpenAIRE

    Phillips, Daniel J.; Congdon, Thomas; Gibson, Matthew I.

    2016-01-01

    Antifreeze (glyco)proteins (AF(G)Ps) have potent ice recrystallisation inhibition (IRI) activity – a desirable phenomenon in applications such as cryopreservation, frozen food and more. In Nature AF(G)P activity is regulated by protein expression levels in response to an environmental stimulus; temperature. However, this level of regulation is not possible in synthetic systems. Here, a synthetic macromolecular mimic is introduced, using supramolecular assembly to regulate activity. Catechol-t...

  15. Activation of Ice Recrystallization Inhibition Activity of Poly(vinyl alcohol) using a Supramolecular Trigger†

    OpenAIRE

    Phillips, Daniel J.; Congdon, Thomas R.; Gibson, Matthew I.

    2016-01-01

    Antifreeze (glyco)proteins (AF(G)Ps) have potent ice recrystallisation inhibition (IRI) activity – a desirable phenomenon in applications such as cryopreservation, frozen food and more. In Nature AF(G)P activity is regulated by protein expression levels in response to an environmental stimulus; temperature. However, this level of regulation is not possible in synthetic systems. Here, a synthetic macromolecular mimic is introduced, using supramolecular assembly to regulate ac...

  16. Progress in the Supramolecular Architecture-directed Synthesis of Perfect Ladder Polysiloxanes

    Institute of Scientific and Technical Information of China (English)

    C; C; Han

    2007-01-01

    1 Introduction Ladder polysiloxanes (LPSs) including organo-bridged ladder polyorganosiloxanes (R-OLPSs, R is side group) and ladder polyorganosilsesquioxanes (R-LPSQs) have intrigued polymer chemists for about 50 years due to their excellent resistance to all kinds of degradations. However, their synthesis has been a great challenge to polymer chemists. Here, we describe a new approach based on supramolecular concerted interactions as follows.2 Results2.1 Synthesis of Perfect R-OLPSsA series of real ...

  17. Is Supramolecular Filament Chirality the Underlying Cause of Major Morphology Differences in Amyloid Fibrils?

    Science.gov (United States)

    2015-01-01

    The unique enhanced sensitivity of vibrational circular dichroism (VCD) to the formation and development of amyloid fibrils in solution is extended to four additional fibril-forming proteins or peptides where it is shown that the sign of the fibril VCD pattern correlates with the sense of supramolecular filament chirality and, without exception, to the dominant fibril morphology as observed in AFM or SEM images. Previously for insulin, it has been demonstrated that the sign of the VCD band pattern from filament chirality can be controlled by adjusting the pH of the incubating solution, above pH 2 for “normal” left-hand-helical filaments and below pH 2 for “reversed” right-hand-helical filaments. From AFM or SEM images, left-helical filaments form multifilament braids of left-twisted fibrils while the right-helical filaments form parallel filament rows of fibrils with a flat tape-like morphology, the two major classes of fibril morphology that from deep UV resonance Raman scattering exhibit the same cross-β-core secondary structure. Here we investigate whether fibril supramolecular chirality is the underlying cause of the major morphology differences in all amyloid fibrils by showing that the morphology (twisted versus flat) of fibrils of lysozyme, apo-α-lactalbumin, HET-s (218–289) prion, and a short polypeptide fragment of transthyretin, TTR (105–115), directly correlates to their supramolecular chirality as revealed by VCD. The result is strong evidence that the chiral supramolecular organization of filaments is the principal underlying cause of the morphological heterogeneity of amyloid fibrils. Because fibril morphology is linked to cell toxicity, the chirality of amyloid aggregates should be explored in the widely used in vitro models of amyloid-associated diseases. PMID:24484302

  18. Vortex-Induced Alignment of a Water Soluble Supramolecular Nanofiber Composed of an Amphiphilic Dendrimer

    Directory of Open Access Journals (Sweden)

    Akihiko Tsuda

    2013-06-01

    Full Text Available We have synthesized a novel amphiphilic naphthalene imide bearing a cationic dendrimer wedge (NID. NID molecules in water self-assemble to form a two-dimensional ribbon, which further coils to give a linear supramolecular nanofiber. The sample solution showed linear dichroism (LD upon stirring of the solution, where NID nanofibers dominantly align at the center of vortex by hydrodynamic interaction with the downward torsional flows.

  19. Is supramolecular filament chirality the underlying cause of major morphology differences in amyloid fibrils?

    Science.gov (United States)

    Kurouski, Dmitry; Lu, Xuefang; Popova, Ludmila; Wan, William; Shanmugasundaram, Maruda; Stubbs, Gerald; Dukor, Rina K; Lednev, Igor K; Nafie, Laurence A

    2014-02-12

    The unique enhanced sensitivity of vibrational circular dichroism (VCD) to the formation and development of amyloid fibrils in solution is extended to four additional fibril-forming proteins or peptides where it is shown that the sign of the fibril VCD pattern correlates with the sense of supramolecular filament chirality and, without exception, to the dominant fibril morphology as observed in AFM or SEM images. Previously for insulin, it has been demonstrated that the sign of the VCD band pattern from filament chirality can be controlled by adjusting the pH of the incubating solution, above pH 2 for "normal" left-hand-helical filaments and below pH 2 for "reversed" right-hand-helical filaments. From AFM or SEM images, left-helical filaments form multifilament braids of left-twisted fibrils while the right-helical filaments form parallel filament rows of fibrils with a flat tape-like morphology, the two major classes of fibril morphology that from deep UV resonance Raman scattering exhibit the same cross-β-core secondary structure. Here we investigate whether fibril supramolecular chirality is the underlying cause of the major morphology differences in all amyloid fibrils by showing that the morphology (twisted versus flat) of fibrils of lysozyme, apo-α-lactalbumin, HET-s (218-289) prion, and a short polypeptide fragment of transthyretin, TTR (105-115), directly correlates to their supramolecular chirality as revealed by VCD. The result is strong evidence that the chiral supramolecular organization of filaments is the principal underlying cause of the morphological heterogeneity of amyloid fibrils. Because fibril morphology is linked to cell toxicity, the chirality of amyloid aggregates should be explored in the widely used in vitro models of amyloid-associated diseases.

  20. Supramolecular Lego assembly towards three-dimensional multi-responsive hydrogels.

    Science.gov (United States)

    Ma, Chunxin; Li, Tiefeng; Zhao, Qian; Yang, Xuxu; Wu, Jingjun; Luo, Yingwu; Xie, Tao

    2014-08-27

    Inspired by the assembly of Lego toys, hydrogel building blocks with heterogeneous responsiveness are assembled utilizing macroscopic supramolecular recognition as the adhesion force. The Lego hydrogel provides 3D transformation upon pH variation. After disassembly of the building blocks by changing the oxidation state, they can be re-assembled into a completely new shape. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. The influence of aquaporin-4 isoform interaction on supramolecular water channel assembly in astrocytoma cells

    OpenAIRE

    Deville, Sarah

    2012-01-01

    Traumatic brain injury (TBI) is often complicated by the development of brain edema. Despite its clinical importance, the underlying pathological mechanisms are poorly understood. Nevertheless, a central role for aquaporin-4 (AQP4) has been suggested. AQP4 is the predominant water channel of the central nervous system, where it forms supramolecular structures named orthogonal arrays of particles (OAP). This organization is essential for channel opening. OAP formation is regulated by the diffe...

  2. Supramolecular solubilization of fullerenes and radio-fullerenes in aqueous media

    International Nuclear Information System (INIS)

    Braun, T.

    1999-01-01

    In this paper we are dealing with the supramolecular complexation of fullerenes C 60 , C 70 , some functionalized fullerenes and of the dumbbell structured C 120 dimer, with two host molecules, namely γ-cyclo-dextrin (GCD), and sulfocalix[8]arene in order to make them soluble in water. Previous investigations by others have shown that the reactions of some mentioned fullerenes and cyclo-dextrins and calixarenes are very slow and tedious in liquid phase as a result of solvatation effects. That we have decided to pursue the supramolecular complexation as solid-solid reactions by using mechanochemical activation in a ball mill. A mechanochemical treatment was used to enhance chemical reactivity in solid-solid reactions in which GCD give a complex with the C 60 as 2:1 host-guest complex. The calix[8]arene complex with C 60 molecule has been prepared. The sulfonated form of the host is well soluble in water. Endohedral radio-fullerenes of the XandC60 type (where * X is a rare gas, e.g. Ar, Xe, Kr, radionuclide) were prepared by nuclear recoil after neutron irradiation, a method developed by the author The endohedrally labelled fullerenes were then mechanochemically complexed into a labelled supramolecular complex with cyclo-dextrin and calixarene hosts. (author)

  3. A chiroptical switch based on supramolecular chirality transfer through alkyl chain entanglement and dynamic covalent bonding.

    Science.gov (United States)

    Lv, Kai; Qin, Long; Wang, Xiufeng; Zhang, Li; Liu, Minghua

    2013-12-14

    Chirality transfer is an interesting phenomenon in Nature, which represents an important step to understand the evolution of chiral bias and the amplification of the chirality. In this paper, we report the chirality transfer via the entanglement of the alkyl chains between chiral gelator molecules and achiral amphiphilic Schiff base. We have found that although an achiral Schiff base amphiphile could not form organogels in any kind of organic solvents, it formed co-organogels when mixed with a chiral gelator molecule. Interestingly, the chirality of the gelator molecules was transferred to the Schiff base chromophore in the mixed co-gels and there was a maximum mixing ratio for the chirality transfer. Furthermore, the supramolecular chirality was also produced based on a dynamic covalent chemistry of an imine formed by the reaction between an aldehyde and an amine. Such a covalent bond of imine was formed reversibly depending on the pH variation. When the covalent bond was formed the chirality transfer occurred, when it was destroyed, the transfer stopped. Thus, a supramolecular chiroptical switch is obtained based on supramolecular chirality transfer and dynamic covalent chemistry.

  4. Supramolecular assembly affording a ratiometric two-photon fluorescent nanoprobe for quantitative detection and bioimaging.

    Science.gov (United States)

    Wang, Peng; Zhang, Cheng; Liu, Hong-Wen; Xiong, Mengyi; Yin, Sheng-Yan; Yang, Yue; Hu, Xiao-Xiao; Yin, Xia; Zhang, Xiao-Bing; Tan, Weihong

    2017-12-01

    Fluorescence quantitative analyses for vital biomolecules are in great demand in biomedical science owing to their unique detection advantages with rapid, sensitive, non-damaging and specific identification. However, available fluorescence strategies for quantitative detection are usually hard to design and achieve. Inspired by supramolecular chemistry, a two-photon-excited fluorescent supramolecular nanoplatform ( TPSNP ) was designed for quantitative analysis with three parts: host molecules (β-CD polymers), a guest fluorophore of sensing probes (Np-Ad) and a guest internal reference (NpRh-Ad). In this strategy, the TPSNP possesses the merits of (i) improved water-solubility and biocompatibility; (ii) increased tissue penetration depth for bioimaging by two-photon excitation; (iii) quantitative and tunable assembly of functional guest molecules to obtain optimized detection conditions; (iv) a common approach to avoid the limitation of complicated design by adjustment of sensing probes; and (v) accurate quantitative analysis by virtue of reference molecules. As a proof-of-concept, we utilized the two-photon fluorescent probe NHS-Ad-based TPSNP-1 to realize accurate quantitative analysis of hydrogen sulfide (H 2 S), with high sensitivity and good selectivity in live cells, deep tissues and ex vivo -dissected organs, suggesting that the TPSNP is an ideal quantitative indicator for clinical samples. What's more, TPSNP will pave the way for designing and preparing advanced supramolecular sensors for biosensing and biomedicine.

  5. Thermo-reversible supramolecular hydrogels of trehalose-type diblock methylcellulose analogues.

    Science.gov (United States)

    Yamagami, Mao; Kamitakahara, Hiroshi; Yoshinaga, Arata; Takano, Toshiyuki

    2018-03-01

    This paper describes the design and synthesis of new trehalose-type diblock methylcellulose analogues with nonionic, cationic, and anionic cellobiosyl segments, namely 1-(tri-O-methyl-cellulosyl)-4-[β-d-glucopyranosyl-(1→4)-β-d-glucopyranosyloxymethyl]-1H-1,2,3-triazole (1), 1-(tri-O-methyl-cellulosyl)-4-[(6-amino-6-deoxy-β-d-glucopyranosyl)-(1→4)- 6-amino-6-deoxy-β-d-glucopyranosyloxymethyl]-1H-1,2,3-triazole (2), and 4-(tri-O-methyl-cellulosyloxymethyl)-1-[β-d-glucopyranuronosyl-(1→4)-β-d-glucopyranuronosyl]-1H-1,2,3-triazole (3), respectively. Aqueous solutions of all of the 1,2,3-triazole-linked diblock methylcellulose analogues possessed higher surface activities than that of industrially produced methylcellulose and exhibited lower critical solution temperatures, that allowed the formation of thermoresponsive supramolecular hydrogels at close to human body temperature. Supramolecular structures of thermo-reversible hydrogels based on compounds 1, 2, and 3 were investigated by means of scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Detailed structure-property-function relationships of compounds 1, 2, and 3 were discussed. Not only nonionic hydrophilic segment but also ionic hydrophilic segments of diblock methylcellulose analogues were valid for the formation of thermo-reversible supramolecular hydrogels based on end-functionalized methylcellulose. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Physical vapor deposited films of a perylene derivative: supramolecular arrangement and thermal stability

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes, Jose Diego; Alessio, Priscila; Silva, Matheus Rodrigues Medeiros; Aroca, Ricardo Flavio; Souza, Agda Eunice de; Constantino, Carlos Jose Leopoldo, E-mail: case@fct.unesp.br [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Presidente Prudente, SP (Brazil). Dept. de Fisica

    2017-07-15

    The analysis of supramolecular arrangement is essential to understand the role of this key factor on the optical and electrical properties of organic thin films. In this work, thin solid films of bis(phenethylimido) perylene (PhPTCD) fabricated using physical vapor deposition (PVD) technique (thermal evaporation), deposited simultaneously onto different substrates (Ag mirror, Ge, and quartz plates) contingent on the characterization technique. The main objective is to study the PhPTCD supramolecular arrangement and the thermal stability of this arrangement in PVD films. The ultraviolet-visible absorption reveals a controlled growth of the PVD films, and the micro-Raman scattering data show that the PhPTCD molecule is not thermally degraded in the conditions of these experiments. The microscopy also shows a homogeneous morphological surface of the PVD film at macro and micro scales, with molecular aggregates at nanoscale. Besides, the PVD film roughness does not follow substrate roughness. The X-ray diffraction indicates a crystalline structure for PhPTCD powder and an amorphous form for PhPTCD PVD film. The infrared absorption spectroscopy points to a preferential flat-on organization of the molecules in the PVD films. In addition, the annealing process (200 deg C for 20 minutes) does not affect the supramolecular arrangement of the PhPTCD PVD films. (author)

  7. A redox responsive, fluorescent supramolecular metallohydrogel consists of nanofibers with single-molecule width

    KAUST Repository

    Zhang, Ye

    2013-04-03

    The integration of a tripeptide derivative, which is a versatile self-assembly motif, with a ruthenium(II)tris(bipyridine) complex affords the first supramolecular metallo-hydrogelator that not only self assembles in water to form a hydrogel but also exhibits gel-sol transition upon oxidation of the metal center. Surprisingly, the incorporation of the metal complex in the hydrogelator results in the nanofibers, formed by the self-assembly of the hydrogelator in water, to have the width of a single molecule of the hydrogelator. These results illustrate that metal complexes, besides being able to impart rich optical, electronic, redox, or magnetic properties to supramolecular hydrogels, also offer a unique geometrical control to prearrange the self-assembly motif prior to self-assembling. The use of metal complexes to modulate the dimensionality of intermolecular interactions may also help elucidate the interactions of the molecular nanofibers with other molecules, thus facilitating the development of supramolecular hydrogel materials for a wide range of applications. © 2013 American Chemical Society.

  8. Self-Healing Natural Rubber with Tailorable Mechanical Properties Based on Ionic Supramolecular Hybrid Network.

    Science.gov (United States)

    Xu, Chuanhui; Cao, Liming; Huang, Xunhui; Chen, Yukun; Lin, Baofeng; Fu, Lihua

    2017-08-30

    In most cases, the strength of self-healing supramolecular rubber based on noncovalent bonds is in the order of KPa, which is a challenge for their further applications. Incorporation of conventional fillers can effectively enhance the strength of rubbers, but usually accompanied by a sacrifice of self-healing capability due to that the filler system is independent of the reversible supramolecular network. In the present work, in situ reaction of methacrylic acid (MAA) and excess zinc oxide (ZnO) was realized in natural rubber (NR). Ionic cross-links in NR matrix were obtained by limiting the covalent cross-linking of NR molecules and allowing the in situ polymerization of MAA/ZnO. Because of the natural affinity between Zn 2+ ion-rich domains and ZnO, the residual nano ZnO participated in formation of a reversible ionic supramolecular hybrid network, thus having little obstructions on the reconstruction of ionic cross-links. Meanwhile, the well dispersed residual ZnO could tailor the mechanical properties of NR by changing the MAA/ZnO molar ratios. The present study thus provides a simple method to fabricate a new self-healing NR with tailorable mechanical properties that may have more potential applications.

  9. Development of a Room Temperature SAW Methane Gas Sensor Incorporating a Supramolecular Cryptophane A Coating

    Directory of Open Access Journals (Sweden)

    Wen Wang

    2016-01-01

    Full Text Available A new room temperature supra-molecular cryptophane A (CrypA-coated surface acoustic wave (SAW sensor for sensing methane gas is presented. The sensor is composed of differential resonator-oscillators, a supra-molecular CrypA coated along the acoustic propagation path, and a frequency signal acquisition module (FSAM. A two-port SAW resonator configuration with low insertion loss, single resonation mode, and high quality factor was designed on a temperature-compensated ST-X quartz substrate, and as the feedback of the differntial oscillators. Prior to development, the coupling of modes (COM simulation was conducted to predict the device performance. The supramolecular CrypA was synthesized from vanillyl alcohol using a double trimerisation method and deposited onto the SAW propagation path of the sensing resonators via different film deposition methods. Experiential results indicate the CrypA-coated sensor made using a dropping method exhibits higher sensor response compared to the unit prepared by the spinning approach because of the obviously larger surface roughness. Fast response and excellent repeatability were observed in gas sensing experiments, and the estimated detection limit and measured sensitivity are ~0.05% and ~204 Hz/%, respectively.

  10. Physical vapor deposited films of a perylene derivative: supramolecular arrangement and thermal stability

    International Nuclear Information System (INIS)

    Fernandes, Jose Diego; Alessio, Priscila; Silva, Matheus Rodrigues Medeiros; Aroca, Ricardo Flavio; Souza, Agda Eunice de; Constantino, Carlos Jose Leopoldo

    2017-01-01

    The analysis of supramolecular arrangement is essential to understand the role of this key factor on the optical and electrical properties of organic thin films. In this work, thin solid films of bis(phenethylimido) perylene (PhPTCD) fabricated using physical vapor deposition (PVD) technique (thermal evaporation), deposited simultaneously onto different substrates (Ag mirror, Ge, and quartz plates) contingent on the characterization technique. The main objective is to study the PhPTCD supramolecular arrangement and the thermal stability of this arrangement in PVD films. The ultraviolet-visible absorption reveals a controlled growth of the PVD films, and the micro-Raman scattering data show that the PhPTCD molecule is not thermally degraded in the conditions of these experiments. The microscopy also shows a homogeneous morphological surface of the PVD film at macro and micro scales, with molecular aggregates at nanoscale. Besides, the PVD film roughness does not follow substrate roughness. The X-ray diffraction indicates a crystalline structure for PhPTCD powder and an amorphous form for PhPTCD PVD film. The infrared absorption spectroscopy points to a preferential flat-on organization of the molecules in the PVD films. In addition, the annealing process (200 deg C for 20 minutes) does not affect the supramolecular arrangement of the PhPTCD PVD films. (author)

  11. Solvent Clathrate Driven Dynamic Stereomutation of a Supramolecular Polymer with Molecular Pockets.

    Science.gov (United States)

    Kulkarni, Chidambar; Korevaar, Peter A; Bejagam, Karteek K; Palmans, Anja R A; Meijer, E W; George, Subi J

    2017-10-04

    Control over the helical organization of synthetic supramolecular systems is intensively pursued to manifest chirality in a wide range of applications ranging from electron spin filters to artificial enzymes. Typically, switching the helicity of supramolecular assemblies involves external stimuli or kinetic traps. However, efforts to achieve helix reversal under thermodynamic control and to understand the phenomena at a molecular level are scarce. Here we present a unique example of helix reversal (stereomutation) under thermodynamic control in the self-assembly of a coronene bisimide that has a 3,5-dialkoxy substitution on the imide phenyl groups (CBI-35CH), leading to "molecular pockets" in the assembly. The stereomutation was observed only if the CBI monomer possesses molecular pockets. Detailed chiroptical studies performed in alkane solvents with different molecular structures reveal that solvent molecules intercalate or form clathrates within the molecular pockets of CBI-35CH at low temperature (263 K), thereby triggering the stereomutation. The interplay among the helical assembly, molecular pockets, and solvent molecules is further unraveled by explicit solvent molecular dynamics simulations. Our results demonstrate how the molecular design of self-assembling building blocks can orchestrate the organization of surrounding solvent molecules, which in turn dictates the helical organization of the resulting supramolecular assembly.

  12. Formation and thermodynamic stability of (polymer + porphyrin) supramolecular structures in aqueous solutions

    International Nuclear Information System (INIS)

    Costa, Viviana C.P. da; Hwang, Barrington J.; Eggen, Spencer E.; Wallace, Megan J.; Annunziata, Onofrio

    2014-01-01

    Highlights: • Thermodynamic stability of a (polymer + porphyrin) supramolecular structure was characterized. • Isothermal titration calorimetry provided two ways to determine reaction enthalpies. • Exothermic (polymer + porphyrin) binding competes with porphyrin self-association. • (Polymer + porphyrin) binding is entropically favored with respect to porphyrin self-association. • Spectral shifts show importance of porphyrin central hydrogens in polymer binding. - Abstract: Optical properties of porphyrins can be tuned through (polymer + porphyrin) (host + guest) binding in solution. This gives rise to the formation of supramolecular structures. In this paper, the formation, thermodynamic stability and spectroscopic properties of (polymer + porphyrin) supramolecular structures and their competition with porphyrin self-association were investigated by both isothermal titration calorimetry (ITC) and absorption spectroscopy. Specifically, reaction enthalpies and equilibrium constants were measured for meso-tetrakis(4-sulfonatophenyl) porphyrin (TPPS) self-association and TPPS binding to the polymer poly(vinylpyrrolidone) (PVP, 40 kg/mol) in aqueous solutions at pH 7 and three different temperatures (12, 25 and 37 °C). ITC, compared to spectroscopic techniques, provides two independent means to determine reaction enthalpies: direct measurements and Van’t Hoff plot. This was used as a criterion to assess that (1) self-association of TPPS is limited to the formation of dimers and (2) TPPS binds to PVP in its monomeric state only. The formation of TPPS dimers and (PVP + TPPS) supramolecular structures are both enthalpically driven. However, (polymer + porphyrin) binding was found to be entropically favored compared to dimerization. Furthermore, the reaction enthalpies of these two processes significantly depend on temperature. This behavior was attributed to hydrophobic interactions. Finally, the limiting absorption spectra of monomeric, dimeric and polymer

  13. Supramolecular Host-Guest System as Ratiometric Fe3+ Ion Sensor Based on Water-Soluble Pillar[5]arene.

    Science.gov (United States)

    Yao, Qianfang; Lü, Baozhong; Ji, Chendong; Cai, Yang; Yin, Meizhen

    2017-10-18

    Developing a specific, ratiometric, and reversible detection method for metal ions is significant to guard against the threat of metal-caused environmental pollution and organisms poisoning. Here a supramolecular host-guest system (WP5⊃G) based on water-soluble pillar[5]arene (WP5) and water-soluble quaternized perylene diimide derivative (G) was constructed. Morphological transformation was achieved during the process of adding WP5 into G aqueous solution, and a fluorescence "turn-off" phenomenon was observed which was caused by supramolecular photoinduced electron transfer (PET). Meanwhile, hydrophobic effect and electrostatic interaction played important roles in this supramolecular process, which was confirmed by isothermal titration calorimeter (ITC) and ζ potential experiments. Furthermore, the supramolecular host-guest system could be a "turn-on" fluorescent probe for Fe 3+ ion detection through the process of interdicting supramolecular PET. Moreover, the Fe 3+ ion detection showed specific, ratiometric, and reversible performances with a detection limit of 2.13 × 10 -7 M, which might have great potentials in biological and environmental monitoring.

  14. Differences in Cellulosic Supramolecular Structure of Compositionally Similar Rice Straw Affect Biomass Metabolism by Paddy Soil Microbiota.

    Directory of Open Access Journals (Sweden)

    Tatsuki Ogura

    Full Text Available Because they are strong and stable, lignocellulosic supramolecular structures in plant cell walls are resistant to decomposition. However, they can be degraded and recycled by soil microbiota. Little is known about the biomass degradation profiles of complex microbiota based on differences in cellulosic supramolecular structures without compositional variations. Here, we characterized and evaluated the cellulosic supramolecular structures and composition of rice straw biomass processed under different milling conditions. We used a range of techniques including solid- and solution-state nuclear magnetic resonance (NMR and Fourier transform infrared spectroscopy followed by thermodynamic and microbial degradability characterization using thermogravimetric analysis, solution-state NMR, and denaturing gradient gel electrophoresis. These measured data were further analyzed using an "ECOMICS" web-based toolkit. From the results, we found that physical pretreatment of rice straw alters the lignocellulosic supramolecular structure by cleaving significant molecular lignocellulose bonds. The transformation from crystalline to amorphous cellulose shifted the thermal degradation profiles to lower temperatures. In addition, pretreated rice straw samples developed different microbiota profiles with different metabolic dynamics during the biomass degradation process. This is the first report to comprehensively characterize the structure, composition, and thermal degradation and microbiota profiles using the ECOMICS toolkit. By revealing differences between lignocellulosic supramolecular structures of biomass processed under different milling conditions, our analysis revealed how the characteristic compositions of microbiota profiles develop in addition to their metabolic profiles and dynamics during biomass degradation.

  15. Water-soluble building blocks for terpyridine-containing supramolecular polymers : synthesis, complexation, and pH stability studies of poly(ethylene oxide) moieties

    NARCIS (Netherlands)

    Lohmeijer, B.G.G.; Schubert, U.S.

    2003-01-01

    Poly(ethylene oxide) of various molecular weights ([bar M ]n = 3 000, 5 200, 10 000, 16 500 g · mol-1) has been modified with terpyridine end groups as building blocks for water-soluble metallo-supramolecular polymers. Metallo-supramolecular A-A homopolymers have been prepared and characterized by

  16. Thermoresponsive Interplay of Water Insoluble Poly(2-alkyl-2-oxazolines Composition and Supramolecular Host–Guest Interactions

    Directory of Open Access Journals (Sweden)

    Victor R. de la Rosa

    2015-04-01

    Full Text Available A series of water insoluble poly[(2-ethyl-2-oxazoline-ran-(2-nonyl-2-oxazoline] amphiphilic copolymers was synthesized and their solubility properties in the presence of different supramolecular host molecules were investigated. The resulting polymer-cavitand assemblies exhibited a thermoresponsive behavior that could be modulated by variation of the copolymer composition and length. Interestingly, the large number of hydrophobic nonyl units across the polymer chain induced the formation of kinetically-trapped nanoparticles in solution. These nanoparticles further agglomerate into larger aggregates at a temperature that is dependent on the polymer composition and the cavitand type and concentration. The present research expands the understanding on the supramolecular interactions between water insoluble copolymers and supramolecular host molecules.

  17. Transfer and Dynamic Inversion of Coassembled Supramolecular Chirality through 2D-Sheet to Rolled-Up Tubular Structure.

    Science.gov (United States)

    Choi, Heekyoung; Cho, Kang Jin; Seo, Hyowon; Ahn, Junho; Liu, Jinying; Lee, Shim Sung; Kim, Hyungjun; Feng, Chuanliang; Jung, Jong Hwa

    2017-12-13

    Transfer and inversion of supramolecular chirality from chiral calix[4]arene analogs (3D and 3L) with an alanine moiety to an achiral bipyridine derivative (1) with glycine moieties in a coassembled hydrogel are demonstrated. Molecular chirality of 3D and 3L could transfer supramolecular chirality to an achiral bipyridine derivative 1. Moreover, addition of 0.6 equiv of 3D or 3L to 1 induced supramolecular chirality inversion of 1. More interestingly, the 2D-sheet structure of the coassembled hydrogels formed with 0.2 equiv of 3D or 3L changed to a rolled-up tubular structure in the presence of 0.6 equiv of 3D or 3L. The chirality inversion and morphology change are mainly mediated by intermolecular hydrogen-bonding interactions between the achiral and chiral molecules, which might be induced by reorientations of the assembled molecules, confirmed by density functional theory calculations.

  18. A Dynamic Combinatorial Approach for Identifying Side Groups that Stabilize DNA-Templated Supramolecular Self-Assemblies

    Directory of Open Access Journals (Sweden)

    Delphine Paolantoni

    2015-02-01

    Full Text Available DNA-templated self-assembly is an emerging strategy for generating functional supramolecular systems, which requires the identification of potent multi-point binding ligands. In this line, we recently showed that bis-functionalized guanidinium compounds can interact with ssDNA and generate a supramolecular complex through the recognition of the phosphodiester backbone of DNA. In order to probe the importance of secondary interactions and to identify side groups that stabilize these DNA-templated self-assemblies, we report herein the implementation of a dynamic combinatorial approach. We used an in situ fragment assembly process based on reductive amination and tested various side groups, including amino acids. The results reveal that aromatic and cationic side groups participate in secondary supramolecular interactions that stabilize the complexes formed with ssDNA.

  19. Self-organization of a self-assembled supramolecular rectangle, square, and three-dimensional cage on Au111 surfaces.

    Science.gov (United States)

    Yuan, Qun-Hui; Wan, Li-Jun; Jude, Hershel; Stang, Peter J

    2005-11-23

    The structure and conformation of three self-assembled supramolecular species, a rectangle, a square, and a three-dimensional cage, on Au111 surfaces were investigated by scanning tunneling microscopy. These supramolecular assemblies adsorb on Au111 surfaces and self-organize to form highly ordered adlayers with distinct conformations that are consistent with their chemical structures. The faces of the supramolecular rectangle and square lie flat on the surface, preserving their rectangle and square conformations, respectively. The three-dimensional cage also forms well-ordered adlayers on the gold surface, forming regular molecular rows of assemblies. When the rectangle and cage were mixed together, the assemblies separated into individual domains, and no mixed adlayers were observed. These results provide direct evidence of the noncrystalline solid-state structures of these assemblies and information about how they self-organize on Au111 surfaces, which is of importance in the potential manufacturing of functional nanostructures and devices.

  20. Self-assembly behavior of a linear-star supramolecular amphiphile based on host-guest complexation.

    Science.gov (United States)

    Wang, Juan; Wang, Xing; Yang, Fei; Shen, Hong; You, Yezi; Wu, Decheng

    2014-11-04

    A star polymer, β-cyclodextrin-poly(l-lactide) (β-CD-PLLA), and a linear polymer, azobenzene-poly(ethylene glycol) (Azo-PEG), could self-assemble into a supramolecular amphiphilic copolymer (β-CD-PLLA@Azo-PEG) based on the host-guest interaction between β-CD and azobenzene moieties. This linear-star supramolecular amphiphilic copolymer further self-assembled into a variety of morphologies, including sphere-like micelle, carambola-like micelle, naan-like micelle, shuttle-like lamellae, tube-like fiber, and random curled-up lamellae, by tuning the length of hydrophilic or hydrophobic chains. The variation of morphology was closely related to the topological structure and block ratio of the supramolecular amphiphiles. These self-assembly structures could disassemble upon an ultraviolet (UV) light irradiation.

  1. Synthesis and Characterization of thermo/pH-responsive Supramolecular G-Quadruplexes for the Construction of Supramolecular Hacky Sacks for Biorelevant Applications

    Science.gov (United States)

    Negron Rios, Luis M.

    The impact of size, shape, and distribution of lipophilic regions on the surfaces of nanoscopic objects that are amphiphilic or patchy (such as proteins) are yet to be fully understood. One of the reasons for this is the lack of an appropriate model systems in which to probe this question. Our group has previously reported 2'-deoxyguanosine (8ArG) derivatives that self-assemble in aqueous media into discrete supramolecular hexadecamers that show the lower critical solution temperature (LCST) phenomenon. The LCST phenomenon is a convenient and rigorous strategy to measure the hydrophobicity of a system. Although these SGQs are potentially attractive for biomedical applications like drug-delivery, the narrow window of physiological temperatures complicates their implementation. This moved us to redesign the constituent 8ArG subunits to incorporate imidazole moieties that would lead to pH-responsive SGQs, working isothermally. Upon reaching a threshold temperature (Lower Critical Solution Temperature, LCST) at pH 7, these dual-responsive SGQs further self-assemble to form nano/micro hydrogel globules that we called them supramolecular hacky sacks (SHS). However, we can isolate kinetically stable versions of these SHS by lowering the ionic strength of the medium (i.e., from the molar to the millimolar range) in a process that we term "fixing the SHS", in which these SHS maintain their integrity (size and shape) and stability without the requirement of crosslinking agents. After structural characterization and in vitro studies of SHS, we performed encapsulation studies of DOX, rhodamine, dsDNA (F26T), thrombin binding aptamer (TBA) and dextran (3 kDa) Texas Red conjugate. Then we performed in vivo studies of cell internalization and drug delivery with neuroblastoma SY-SH5Y. The performed studies will bring new approaches for the development of new biotechnology for fundamental applications and the emerging of novel therapeutic agents for biomedical applications.

  2. Fabrication of supramolecular star-shaped amphiphilic copolymers for ROS-triggered drug release.

    Science.gov (United States)

    Zuo, Cai; Peng, Jinlei; Cong, Yong; Dai, Xianyin; Zhang, Xiaolong; Zhao, Sijie; Zhang, Xianshuo; Ma, Liwei; Wang, Baoyan; Wei, Hua

    2018-03-15

    Star-shaped copolymers with branched structures can form unimolecular micelles with better stability than the micelles self-assembled from conventional linear copolymers. However, the synthesis of star-shaped copolymers with precisely controlled degree of branching (DB) suffers from complicated sequential polymerizations and multi-step purification procedures, as well as repeated optimizations of polymer compositions. The use of a supramolecular host-guest pair as the block junction would significantly simplify the preparation. Moreover, the star-shaped copolymer-based unimolecular micelle provides an elegant solution to the tradeoff between extracellular stability and intracellular high therapeutic efficacy if the association/dissociation of the supramolecular host-guest joint can be triggered by the biologically relevant stimuli. For this purpose, in this study, a panel of supramolecular star-shaped amphiphilic block copolymers with 9, 12, and 18 arms were designed and fabricated by host-guest complexations between the ring-opening polymerization (ROP)-synthesized star-shaped poly(ε-caprolactone) (PCL) with 3, 4, and 6 arms end-capped with ferrocene (Fc) (PCL-Fc) and the atom transfer radical polymerization (ATRP)-produced 3-arm poly(oligo ethylene glycol) methacrylates (POEGMA) with different degrees of polymerization (DPs) of 24, 30, 47 initiated by β-cyclodextrin (β-CD) (3Br-β-CD-POEGMA). The effect of DB and polymer composition on the self-assembled properties of the five star-shaped copolymers was investigated by dynamic light scattering (DLS), transmission electron microscopy (TEM), and fluorescence spectrometery. Interestingly, the micelles self-assembled from 12-arm star-shaped copolymers exhibited greater stability than the 9- and 18-arm formulations. The potential of the resulting supramolecular star-shaped amphiphilic copolymers as drug carriers was evaluated by an in vitro drug release study, which confirmed the ROS-triggered accelerated drug

  3. Cross-Linked Fluorescent Supramolecular Nanoparticles as Finite Tattoo Pigments with Controllable Intradermal Retention Times.

    Science.gov (United States)

    Choi, Jin-Sil; Zhu, Yazhen; Li, Hongsheng; Peyda, Parham; Nguyen, Thuy Tien; Shen, Mo Yuan; Yang, Yang Michael; Zhu, Jingyi; Liu, Mei; Lee, Mandy M; Sun, Shih-Sheng; Yang, Yang; Yu, Hsiao-Hua; Chen, Kai; Chuang, Gary S; Tseng, Hsian-Rong

    2017-01-24

    Tattooing has been utilized by the medical community for precisely demarcating anatomic landmarks. This practice is especially important for identifying biopsy sites of nonmelanoma skin cancer (NMSC) due to the long interval (i.e., up to 3 months) between the initial diagnostic biopsy and surgical treatment. Commercially available tattoo pigments possess several issues, which include causing poor cosmesis, being mistaken for a melanocytic lesion, requiring additional removal procedures when no longer desired, and potentially inducing inflammatory responses. The ideal tattoo pigment for labeling of skin biopsy sites for NMSC requires (i) invisibility under ambient light, (ii) fluorescence under a selective light source, (iii) a finite intradermal retention time (ca. 3 months), and (iv) biocompatibility. Herein, we introduce cross-linked fluorescent supramolecular nanoparticles (c-FSNPs) as a "finite tattoo" pigment, with optimized photophysical properties and intradermal retention time to achieve successful in vivo finite tattooing. Fluorescent supramolecular nanoparticles encapsulate a fluorescent conjugated polymer, poly[5-methoxy-2-(3-sulfopropoxy)-1,4-phenylenevinylene] (MPS-PPV), into a core via a supramolecular synthetic approach. FSNPs which possess fluorescent properties superior to those of the free MPS-PPV are obtained through a combinatorial screening process. Covalent cross-linking of FSNPs results in micrometer-sized c-FSNPs, which exhibit a size-dependent intradermal retention. The 1456 nm sized c-FSNPs display an ideal intradermal retention time (ca. 3 months) for NMSC lesion labeling, as observed in an in vivo tattoo study. In addition, the c-FSNPs induce undetectable inflammatory responses after tattooing. We believe that the c-FSNPs can serve as a "finite tattoo" pigment to label potential malignant NMSC lesions.

  4. Supramolecular packing and polymorph screening of N-isonicotinoyl arylketone hydrazones with phenol and amino modifications

    Science.gov (United States)

    Hean, Duane; Michael, Joseph P.; Lemmerer, Andreas

    2018-04-01

    Thirteen structural variants based on the (E)-N‧-(1-arylethylidene)pyridohydrazide template were prepared, investigated and screened for possible polymorphic behaviour. Four variants showed from Differential Scanning Calorimetry Scans thermal events indicative of new solid-state phases. The thirteen variants included substituents R = sbnd OH or sbnd NH2 placed at ortho, meta and para positions on the phenyl ring; and shifting the pyridyl nitrogen between positions 4-, 3- and 2-. The crystal structures of twelve of the compounds were determined to explore their supramolecular structures. The outcomes of these modifications demonstrated that the pyridyl nitrogen at the 2- position is 'locked' by forming a hydrogen bond with the amide hydrogen; while placing the pyridyl nitrogen at positions 3- and 4- offers a greater opportunity for hydrogen bonding with neighbouring molecules. Such interactions include Osbnd H⋯N, Nsbnd H⋯N, Osbnd H⋯O, Nsbnd H⋯O, Nsbnd H⋯π, π⋯π stacking, as well as other weaker interactions such as Csbnd H⋯N, Csbnd H⋯O, Csbnd H⋯N(pyridyl). When OH or NH2 donors are placed in the ortho position, an intramolecular hydrogen bond is formed between the acceptor hydrazone nitrogen and the respective donor. The meta- and para-positioned donors form an unpredictable array of supramolecular structures by forming hydrogen-bonded chains with the pyridyl nitrogen and carbonyl acceptors respectively. In addition to the intramolecular and chain hydrogen bond formation demonstrated throughout the crystal structures under investigation, larger order hydrogen-bonded rings were also observed in some of the supramolecular aggregations. The extent of the hydrogen-bonded ring formations range from two to six molecular participants depending on the specific crystal structure.

  5. Self assembly of amphiphilic C60 fullerene derivatives into nanoscale supramolecular structures

    Directory of Open Access Journals (Sweden)

    Casscells S Ward

    2007-08-01

    Full Text Available Abstract Background The amphiphilic fullerene monomer (AF-1 consists of a "buckyball" cage to which a Newkome-like dendrimer unit and five lipophilic C12 chains positioned octahedrally to the dendrimer unit are attached. In this study, we report a novel fullerene-based liposome termed 'buckysome' that is water soluble and forms stable spherical nanometer sized vesicles. Cryogenic electron microscopy (Cryo-EM, transmission electron microscopy (TEM, and dynamic light scattering (DLS studies were used to characterize the different supra-molecular structures readily formed from the fullerene monomers under varying pH, aqueous solvents, and preparative conditions. Results Electron microscopy results indicate the formation of bilayer membranes with a width of ~6.5 nm, consistent with previously reported molecular dynamics simulations. Cryo-EM indicates the formation of large (400 nm diameter multilamellar, liposome-like vesicles and unilamellar vesicles in the size range of 50–150 nm diameter. In addition, complex networks of cylindrical, tube-like aggregates with varying lengths and packing densities were observed. Under controlled experimental conditions, high concentrations of spherical vesicles could be formed. In vitro results suggest that these supra-molecular structures impose little to no toxicity. Cytotoxicity of 10–200 μM buckysomes were assessed in various cell lines. Ongoing studies are aimed at understanding cellular internalization of these nanoparticle aggregates. Conclusion In this current study, we have designed a core platform based on a novel amphiphilic fullerene nanostructure, which readily assembles into supra-molecular structures. This delivery vector might provide promising features such as ease of preparation, long-term stability and controlled release.

  6. Molecular self-assembly approaches for supramolecular electronic and organic electronic devices

    Science.gov (United States)

    Yip, Hin-Lap

    Molecular self-assembly represents an efficient bottom-up strategy to generate structurally well-defined aggregates of semiconducting pi-conjugated materials. The capability of tuning the chemical structures, intermolecular interactions and nanostructures through molecular engineering and novel materials processing renders it possible to tailor a large number of unprecedented properties such as charge transport, energy transfer and light harvesting. This approach does not only benefit traditional electronic devices based on bulk materials, but also generate a new research area so called "supramolecular electronics" in which electronic devices are built up with individual supramolecular nanostructures with size in the sub-hundred nanometers range. My work combined molecular self-assembly together with several novel materials processing techniques to control the nucleation and growth of organic semiconducting nanostructures from different type of pi-conjugated materials. By tailoring the interactions between the molecules using hydrogen bonds and pi-pi stacking, semiconducting nanoplatelets and nanowires with tunable sizes can be fabricated in solution. These supramolecular nanostructures were further patterned and aligned on solid substrates through printing and chemical templating methods. The capability to control the different hierarchies of organization on surface provides an important platform to study their structural-induced electronic properties. In addition to using molecular self-assembly to create different organic nanostructures, functional self-assembled monolayer (SAM) formed by spontaneous chemisorption on surfaces was used to tune the interfacial property in organic solar cells. Devices showed dramatically improved performance when appropriate SAMs were applied to optimize the contact property for efficiency charge collection.

  7. Hydrodynamic and Thermophoretic Effects on the Supramolecular Chirality of Pyrene-Derived Nanosheets.

    Science.gov (United States)

    Micali, Norberto; Vybornyi, Mykhailo; Mineo, Placido; Khorev, Oleg; Häner, Robert; Villari, Valentina

    2015-06-22

    Chiroptical properties of two-dimensional (2D) supramolecular assemblies (nanosheets) of achiral, charged pyrene trimers (Py3 ) are rendered chiral by asymmetric physical perturbations. Chiral stimuli in a cuvette can originate either from controlled temperature gradients or by very gentle stirring. The chiroptical activity strongly depends on the degree of supramolecular order of the nanosheets, which is easily controlled by the method of preparation. The high degree of structural order ensures strong cooperative effects within the aggregates, rendering them more susceptible to external stimuli. The samples prepared by using slow thermal annealing protocols are both CD and LD active (in stagnant and stirred solutions), whereas for isothermally aged samples chiroptical activity was in all cases undetectable. In the case of temperature gradients, the optical activity of 2D assemblies could be recorded for a stagnant solution due to migration of the aggregates from the hottest to the coldest regions of the system. However, a considerably stronger exciton coupling, coinciding with the J-band of the interacting pyrenes, is developed upon subtle vortexing (0.5 Hz, 30 rpm) of the aqueous solution of the nanosheets. The sign of the exciton coupling is inverted upon switching between clockwise and counter-clockwise rotation. The supramolecular chirality is evidenced by the appearance of CD activity. To exclude artefacts from proper CD spectra, the contribution from LD to the observed CD was determined. The data suggest that the aggregates experience asymmetrical deformation and alignment effects because of the presence of chiral flows. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Two new hydrogen bond-supported supramolecular compounds assembly from polyoxovanadate and organoamines

    International Nuclear Information System (INIS)

    Duan Weijie; Cui Xiaobing; Xu Yan; Xu Jiqing; Yu Haihui; Yi Zhihui; Cui Jiwen; Wang Tiegang

    2007-01-01

    Two novel organic-inorganic hybrid compounds based on organoamines and polyoxovanadates formulated as (H 2 dien) 4 [H 10 V 18 O 42 (PO 4 )](PO 4 ).2H 2 O (1) (dien=diethylenetriamine) and (Him) 8 [HV 18 O 42 (PO 4 )] (2) (im=imidazole) have been prepared under hydrothermal conditions by using different starting materials, and characterized by elemental analyses, IR, ESR, XPS, TGA and single-crystal X-ray diffraction analyses. Crystal data for compound 1: C 16 H 74 N 12 O 52 V 18 P 2 , Monoclinic, space group C2/c, a=23.9593(4) A, b=13.0098(2) A, c=20.1703(4) A, β=105.566(3) o , V=6056.6(19) A 3 , Z=4; for compound 2, C 24 H 41 N 16 O 46 V 18 P, Tetragonal, space group I4/mmm, a=13.5154(8) A, b=13.5154(8) A, c=19.1136 A, β=90 o , V=3491.4(3) A 3 , Z=2. Compound 1 consists of protonated diens together with polyoxovanadates [H 10 V 18 O 42 (PO 4 )] 5- . Compound 2 is composed of protonated ims and polyoxovanadates [HV 18 O 42 (PO 4 )] 8- . There are hydrogen-bonding interactions between polyoxovanadates and different organoamines in 1 and 2. Polyoxovanadates are linked through H 2 dien into a three-dimensional network via hydrogen bonds in 1, while polyoxovanadates are linked by Him into a two-dimensional layer network via hydrogen bonds in 2. The crystal packing patterns of the two compounds reveal various supramolecular frameworks. - Graphical abstract: Two new organic-inorganic hybrid compounds based on [V 18 O 42 (PO 4 )] building blocks have been hydrothermally synthesized. 1 is the first 3-D supramolecular network structure consisting of [V 18 O 42 (PO 4 )] unit, while 2 possesses 2-D layered supramolecular structure

  9. Supramolecular nanoparticles generated by the self-assembly of polyrotaxanes for antitumor drug delivery

    Directory of Open Access Journals (Sweden)

    Liu R

    2012-10-01

    Full Text Available Rong Liu,1,2,* Yusi Lai,1,* Bin He,1 Yuan Li,1 Gang Wang,1 Shuang Chang,1 Zhongwei Gu1 1National Engineering Research Center for Biomaterials, Sichuan University, Chengdu, China; 2Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China*These authors contributed equally to this paperAbstract: A new approach of fabricating supramolecular nanoparticles generated by self-assembly polyrotaxanes for antitumor drug delivery has been reported. Cinnamic-acid-modified poly(ethylene glycol chains were threaded in a-cyclodextrins to form polyrotaxanes. The polyrotaxanes self-assembled supramolecular nanoparticles. The morphology of the nanoparticles was changed from nanovesicle to micelle after the antitumor drug, doxorubicin, was loaded. The release profile of the drug-loaded nanoparticles was investigated, and it was found that the sustaining release time could last for 32 hours. The drug-loaded nanoparticles were co-cultured with mouse 4T1 breast cancer cells with a drug concentration of 10 µg/mL; the cell survival rate was 3.3% after a 72-hour incubation. In an in vivo study of breast cancer in a mouse model, the drug-loaded nanoparticles were injected in the tail veins of mice with a dose of 5 mg/kg body weight. The tumor inhibition rate of drug-loaded nanoparticles was 53%, which was better than that of doxorubicin hydrochloride. The cardiac toxicity of doxorubicin was decreased greatly after the encapsulation into supramolecular polyrotaxane nanoparticles.Keywords: polyrotaxane, self-assembly, nanoparticle, doxorubicin, supermolecular

  10. Graphene controlled H- and J-stacking of perylene dyes into highly stable supramolecular nanostructures for enhanced photocurrent generation

    DEFF Research Database (Denmark)

    Gan, Shiyu; Zhong, Lijie; Engelbrekt, Christian

    2014-01-01

    We report a new method for controlling H- and J-stacking in supramolecular self-assembly. Graphene nanosheets act as structure inducers to direct the self-assembly of a versatile organic dye, perylene into two distinct types of functional nanostructures, i.e. one-dimensional nanotubes via J......-stacking and two-dimensional branched nanobuds through H-stacking. Graphene integrated supramolecular nanocomposites are highly stable and show significant enhancement of photocurrent generation in these two configurations of photosensing devices, i.e. solid-state optoelectronic constructs and liquid...

  11. Metal-driven and covalent synthesis of supramolecular grids from racks: a convergent approach to heterometallic and heteroleptic nanostructures.

    Science.gov (United States)

    Schmittel, Michael; Kalsani, Venkateshwarlu; Bats, Jan W

    2005-06-13

    Supramolecular nanogrids were prepared from dynamic supramolecular racks through the coupling of terminal alkynes using either a covalent (with CuCl/O(2)) or a coordinative (with [trans-(PEt(3))(2)PtCl(2)]) approach. Because of the rapid equilibration of the racks (as tested by exchange reactions), oligomeric adducts potentially formed in the coupling process will selectively furnish the nanogrids through an entropically driven self-repair mechanism. To ascertain the structural assignment, the nanogrids were also synthesized by an independent strategy.

  12. Supramolecular chemistry at interfaces: host-guest interactions for fabricating multifunctional biointerfaces.

    Science.gov (United States)

    Yang, Hui; Yuan, Bin; Zhang, Xi; Scherman, Oren A

    2014-07-15

    CONSPECTUS: Host-guest chemistry can greatly improve the selectivity of biomolecule-ligand binding on account of recognition-directed interactions. In addition, functional structures and the actuation of supramolecular assemblies in molecular systems can be controlled efficiently through various host-guest chemistry. Together, these highly selective, strong yet dynamic interactions can be exploited as an alternative methodology for applications in the field of programmable and controllable engineering of supramolecular soft materials through the reversible binding between complementary components. Many processes in living systems such as biotransformation, transportation of matter, and energy transduction begin with interfacial molecular recognition, which is greatly influenced by various external stimuli at biointerfaces. Detailed investigations about the molecular recognition at interfaces can result in a better understanding of life science, and further guide us in developing new biomaterials and medicines. In order to mimic complicated molecular-recognition systems observed in nature that adapt to changes in their environment, combining host-guest chemistry and surface science is critical for fabricating the next generation of multifunctional biointerfaces with efficient stimuli-responsiveness and good biocompatibility. In this Account, we will summarize some recent progress on multifunctional stimuli-responsive biointerfaces and biosurfaces fabricated by cyclodextrin- or cucurbituril-based host-guest chemistry and highlight their potential applications including drug delivery, bioelectrocatalysis, and reversible adsorption and resistance of peptides, proteins, and cells. In addition, these biointerfaces and biosurfaces demonstrate efficient response toward various external stimuli, such as UV light, pH, redox chemistry, and competitive guests. All of these external stimuli can aid in mimicking the biological stimuli evident in complex biological environments

  13. A new supramolecular route for using Rod-Coil block copolymers in photovoltaic applications

    Energy Technology Data Exchange (ETDEWEB)

    Sary, Nicolas [Department of Physics and FRIMAT Center for Nanomaterials, University of Fribourg (Switzerland); Richard, Fanny; Brochon, Cyril; Leclerc, Nicolas; Hadziioannou, Georges [Laboratoire d' Ingenierie des Polymeres pour les Hautes Technologies Universite de Strasbourg, Ecole Europeenne de Chimie Polymeres et Materiaux (France); Leveque, Patrick; Heiser, Thomas [Institut d' Electronique du Solide et des Systemes Centre National de la Recherche Scientifique, Universite de Strasbourg (France); Audinot, Jean-Nicolas [Science and Analysis of Materials Department Public Research Centre Gabriel Lippmann, Belvaux (Luxembourg); Berson, Solenn [Laboratoire des Composants Solaires, Institut de l' Energie Solaire Commissariat a l' energie atomique, Le Bourget Du Lac (France); Mezzenga, Raffaele [Department of Physics and FRIMAT Center for Nanomaterials, University of Fribourg (Switzerland); Nestle Research Center, Lausanne (Switzerland)

    2010-02-09

    A new polymer blend formed by poly(3-hexylthiophene)-poly(4-vinylpyridine) (P3HT- P4VP) block copolymers and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) is reported. The P4VP and PCBM are mixed together by weak supramolecular interactions, and the resulting materials exhibit microphase separated morphologies of electron-donor and electron-acceptor rich domains. The properties of the blend, used in photovoltaic devices as active layers, are also discussed. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  14. Two-photon absorption of a supramolecular pseudoisocyanine J-aggregate assembly

    International Nuclear Information System (INIS)

    Belfield, Kevin D.; Bondar, Mykhailo V.; Hernandez, Florencio E.; Przhonska, Olga V.; Yao, Sheng

    2006-01-01

    Linear spectral properties, including excitation anisotropy, of pseudoisocyanine or 1,1'-diethyl-2,2'-cyanine iodide (PIC) J-aggregates in aqueous solutions with J-band position at 573 nm were investigated. Two-photon absorption of PIC J-aggregates and monomer molecules was studied using an open aperture Z-scan technique. A strong enhancement of the two-photon absorption cross-section of PIC in the supramolecular J-aggregate assembly was observed in aqueous solution. This enhancement is attributed to a strong coupling of the molecular transition dipoles. No two-photon absorption at the peak of the J-band was detected

  15. Supramolecular architectures of iron phthalocyanine Langmuir-Blodgett films: The role played by the solution solvents

    Science.gov (United States)

    Rubira, Rafael Jesus Gonçalves; Aoki, Pedro Henrique Benites; Constantino, Carlos José Leopoldo; Alessio, Priscila

    2017-09-01

    The developing of organic-based devices has been widely explored using ultrathin films as the transducer element, whose supramolecular architecture plays a central role in the device performance. Here, Langmuir and Langmuir-Blodgett (LB) ultrathin films were fabricated from iron phthalocyanine (FePc) solutions in chloroform (CHCl3), dichloromethane (CH2Cl2), dimethylformamide (DMF), and tetrahydrofuran (THF) to determine the influence of different solvents on the supramolecular architecture of the ultrathin films. The UV-vis absorption spectroscopy shows a strong dependence of the FePc aggregation on these solvents. As a consequence, the surface pressure vs. mean molecular area (π-A) isotherms and Brewster angle microscopy (BAM) reveal a more homogeneous (surface morphology) Langmuir film at the air/water interface for FePc in DMF. The same morphological pattern observed for the Langmuir films is preserved upon LB deposition onto solid substrates. The Raman and FTIR analyses indicate the DMF-FePc interaction relies on coordination bonds between N atom (from DMF) and Fe atom (from FePc). Besides, the FePc molecular organization was also found to be affected by the DMF-FePc chemical interaction. It is interesting to note that, if the DMF-FePc leads to less aggregated FePc either in solution or ultrathin films (Langmuir and LB), with time (one week) the opposite trend is found. Taking into account the N-Fe interaction, the performance of the FePc ultrathin films with distinct supramolecular architectures composing sensing units was explored as proof-of-principle in the detection of trace amounts of atrazine herbicide in water using impedance spectroscopy. Further statistical and computational analysis reveal not only the role played by FePc supramolecular architecture but also the sensitivity of the system to detect atrazine solutions down to 10-10 mol/L, which is sufficient to monitor the quality of drinking water even according to the most stringent international

  16. Hierarchical assembly of branched supramolecular polymers from (cyclic Peptide)-polymer conjugates.

    Science.gov (United States)

    Koh, Ming Liang; Jolliffe, Katrina A; Perrier, Sébastien

    2014-11-10

    We report the synthesis and assembly of (N-methylated cyclic peptide)-polymer conjugates for which the cyclic peptide is attached to either the α- or both α- and ω- end groups of a polymer. A combination of chromatographic, spectroscopic, and scattering techniques reveals that the assembly of the conjugates follows a two-level hierarchy, initially driven by H-bond formation between two N-methylated cyclic peptides, followed by unspecific, noncovalent aggregation of this peptide into small domains that behave as branching points and lead to the formation of branched supramolecular polymers.

  17. Artificial muscle-like function from hierarchical supramolecular assembly of photoresponsive molecular motors.

    Science.gov (United States)

    Chen, Jiawen; Leung, Franco King-Chi; Stuart, Marc C A; Kajitani, Takashi; Fukushima, Takanori; van der Giessen, Erik; Feringa, Ben L

    2018-02-01

    A striking feature of living systems is their ability to produce motility by amplification of collective molecular motion from the nanoscale up to macroscopic dimensions. Some of nature's protein motors, such as myosin in muscle tissue, consist of a hierarchical supramolecular assembly of very large proteins, in which mechanical stress induces a coordinated movement. However, artificial molecular muscles have often relied on covalent polymer-based actuators. Here, we describe the macroscopic contractile muscle-like motion of a supramolecular system (comprising 95% water) formed by the hierarchical self-assembly of a photoresponsive amphiphilic molecular motor. The molecular motor first assembles into nanofibres, which further assemble into aligned bundles that make up centimetre-long strings. Irradiation induces rotary motion of the molecular motors, and propagation and accumulation of this motion lead to contraction of the fibres towards the light source. This system supports large-amplitude motion, fast response, precise control over shape, as well as weight-lifting experiments in water and air.

  18. Artificial muscle-like function from hierarchical supramolecular assembly of photoresponsive molecular motors

    Science.gov (United States)

    Chen, Jiawen; Leung, Franco King-Chi; Stuart, Marc C. A.; Kajitani, Takashi; Fukushima, Takanori; van der Giessen, Erik; Feringa, Ben L.

    2018-02-01

    A striking feature of living systems is their ability to produce motility by amplification of collective molecular motion from the nanoscale up to macroscopic dimensions. Some of nature's protein motors, such as myosin in muscle tissue, consist of a hierarchical supramolecular assembly of very large proteins, in which mechanical stress induces a coordinated movement. However, artificial molecular muscles have often relied on covalent polymer-based actuators. Here, we describe the macroscopic contractile muscle-like motion of a supramolecular system (comprising 95% water) formed by the hierarchical self-assembly of a photoresponsive amphiphilic molecular motor. The molecular motor first assembles into nanofibres, which further assemble into aligned bundles that make up centimetre-long strings. Irradiation induces rotary motion of the molecular motors, and propagation and accumulation of this motion lead to contraction of the fibres towards the light source. This system supports large-amplitude motion, fast response, precise control over shape, as well as weight-lifting experiments in water and air.

  19. Multivalency at Interfaces: Supramolecular Carbohydrate-Functionalized Graphene Derivatives for Bacterial Capture, Release, and Disinfection.

    Science.gov (United States)

    Qi, Zhenhui; Bharate, Priya; Lai, Chian-Hui; Ziem, Benjamin; Böttcher, Christoph; Schulz, Andrea; Beckert, Fabian; Hatting, Benjamin; Mülhaupt, Rolf; Seeberger, Peter H; Haag, Rainer

    2015-09-09

    A supramolecular carbohydrate-functionalized two-dimensional (2D) surface was designed and synthesized by decorating thermally reduced graphene sheets with multivalent sugar ligands. The formation of host-guest inclusions on the carbon surface provides a versatile strategy, not only to increase the intrinsic water solubility of graphene-based materials, but more importantly to let the desired biofunctional binding groups bind to the surface. Combining the vital recognition role of carbohydrates and the unique 2D large flexible surface area of the graphene sheets, the addition of multivalent sugar ligands makes the resulting carbon material an excellent platform for selectively wrapping and agglutinating Escherichia coli (E. coli). By taking advantage of the responsive property of supramolecular interactions, the captured bacteria can then be partially released by adding a competitive guest. Compared to previously reported scaffolds, the unique thermal IR-absorption properties of graphene derivatives provide a facile method to kill the captured bacteria by IR-laser irradiation of the captured graphene-sugar-E. coli complex.

  20. A Glycyrrhetinic Acid-Modified Curcumin Supramolecular Hydrogel for liver tumor targeting therapy

    Science.gov (United States)

    Chen, Guoqin; Li, Jinliang; Cai, Yanbin; Zhan, Jie; Gao, Jie; Song, Mingcai; Shi, Yang; Yang, Zhimou

    2017-03-01

    Curcumin (Cur), a phenolic anti-oxidant compound obtained from Curcuma longa plant, possesses a variety of therapeutic properties. However, it is suffered from its low water solubility and low bioavailability property, which seriously restricts its clinical application. In this study, we developed a glycyrrhetinic acid (GA) modified curcumin supramolecular pro-gelator (GA-Cur) and a control compound Nap-Cur by replacing GA with the naphthylacetic acid (Nap). Both compounds showed good water solubility and could form supramolecular gels by disulfide bond reduction triggered by glutathione (GSH) in vitro. Both formed gels could sustainedly release Cur in buffer solutions. We also investigated the cytotoxicity of pro-gelators to HepG2 cells by a MTT assay and determined the cellular uptake behaviours of them by fluorescence microscopy and LC-MS. Due to the over expression of GA receptor in liver cancer cells, our pro-gelator of GA-Cur showed an enhanced cellular uptake and better inhibition capacity to liver tumor cells than Nap-Cur. Therefore, the GA-Cur could significantly inhibit HepG2 cell growth. Our study provides a novel nanomaterial for liver tumor chemotherapy.

  1. Strong and Robust Polyaniline-Based Supramolecular Hydrogels for Flexible Supercapacitors.

    Science.gov (United States)

    Li, Wanwan; Gao, Fengxian; Wang, Xiaoqian; Zhang, Ning; Ma, Mingming

    2016-08-01

    We report a supramolecular strategy to prepare conductive hydrogels with outstanding mechanical and electrochemical properties, which are utilized for flexible solid-state supercapacitors (SCs) with high performance. The supramolecular assembly of polyaniline and polyvinyl alcohol through dynamic boronate bond yields the polyaniline-polyvinyl alcohol hydrogel (PPH), which shows remarkable tensile strength (5.3 MPa) and electrochemical capacitance (928 F g(-1) ). The flexible solid-state supercapacitor based on PPH provides a large capacitance (306 mF cm(-2) and 153 F g(-1) ) and a high energy density of 13.6 Wh kg(-1) , superior to other flexible supercapacitors. The robustness of the PPH-based supercapacitor is demonstrated by the 100 % capacitance retention after 1000 mechanical folding cycles, and the 90 % capacitance retention after 1000 galvanostatic charge-discharge cycles. The high activity and robustness enable the PPH-based supercapacitor as a promising power device for flexible electronics. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Automatic Assignment of Methyl-NMR Spectra of Supramolecular Machines Using Graph Theory.

    Science.gov (United States)

    Pritišanac, Iva; Degiacomi, Matteo T; Alderson, T Reid; Carneiro, Marta G; Ab, Eiso; Siegal, Gregg; Baldwin, Andrew J

    2017-07-19

    Methyl groups are powerful probes for the analysis of structure, dynamics and function of supramolecular assemblies, using both solution- and solid-state NMR. Widespread application of the methodology has been limited due to the challenges associated with assigning spectral resonances to specific locations within a biomolecule. Here, we present Methyl Assignment by Graph Matching (MAGMA), for the automatic assignment of methyl resonances. A graph matching protocol examines all possibilities for each resonance in order to determine an exact assignment that includes a complete description of any ambiguity. MAGMA gives 100% accuracy in confident assignments when tested against both synthetic data, and 9 cross-validated examples using both solution- and solid-state NMR data. We show that this remarkable accuracy enables a user to distinguish between alternative protein structures. In a drug discovery application on HSP90, we show the method can rapidly and efficiently distinguish between possible ligand binding modes. By providing an exact and robust solution to methyl resonance assignment, MAGMA can facilitate significantly accelerated studies of supramolecular machines using methyl-based NMR spectroscopy.

  3. Supramolecular Chirality: Solvent Chirality Transfer in Molecular Chemistry and Polymer Chemistry

    Directory of Open Access Journals (Sweden)

    Michiya Fujiki

    2014-08-01

    Full Text Available Controlled mirror symmetry breaking arising from chemical and physical origin is currently one of the hottest issues in the field of supramolecular chirality. The dynamic twisting abilities of solvent molecules are often ignored and unknown, although the targeted molecules and polymers in a fluid solution are surrounded by solvent molecules. We should pay more attention to the facts that mostly all of the chemical and physical properties of these molecules and polymers in the ground and photoexcited states are significantly influenced by the surrounding solvent molecules with much conformational freedom through non-covalent supramolecular interactions between these substances and solvent molecules. This review highlights a series of studies that include: (i historical background, covering chiral NaClO3 crystallization in the presence of d-sugars in the late 19th century; (ii early solvent chirality effects for optically inactive chromophores/fluorophores in the 1960s–1980s; and (iii the recent development of mirror symmetry breaking from the corresponding achiral or optically inactive molecules and polymers with the help of molecular chirality as the solvent use quantity.

  4. Enzyme-Like Catalysis of the Nazarov Cyclization by Supramolecular Encapsulation

    Energy Technology Data Exchange (ETDEWEB)

    Hastings, Courtney; Pluth, Michael; Bergman, Robert; Raymond, Kenneth

    2010-03-29

    A primary goal in the design and synthesis of molecular hosts has been the selective recognition and binding of a variety of guests using non-covalent interactions. Supramolecular catalysis, which is the application of such hosts towards catalysis, has much in common with many enzymatic reactions, chiefly the use of both spatially appropriate binding pockets and precisely oriented functional groups to recognize and activate specific substrate molecules. Although there are now many examples which demonstrate how selective encapsulation in a host cavity can enhance the reactivity of a bound guest, all have failed to reach the degree of increased reactivity typical of enzymes. We now report the catalysis of the Nazarov cyclization by a self-assembled coordination cage, a carbon-carbon bond-forming reaction which proceeds under mild, aqueous conditions. The acceleration in this system is over a million-fold, and represents the first example of supramolecular catalysis that achieves the level of rate enhancement comparable to that observed in several enzymes. We explain the unprecedented degree of rate increase as due to the combination of (a) preorganization of the encapsulated substrate molecule, (b) stabilization of the transition state of the cyclization by constrictive binding, and (c) increase in the basicity of the complexed alcohol functionality.

  5. The dominant role of side chains in supramolecular double helical organisation in synthetic tripeptides

    Science.gov (United States)

    Sharma, Ankita; Tiwari, Priyanka; Dutt Konar, Anita

    2018-06-01

    Peptide self-assembled nanostructures have attracted attention recently owing to their promising applications in diversified avenues. To validate the importance of sidechains in supramolecular architectural stabilization, herein this report describes the self-assembly propensities involving weak interactions in a series of model tripeptides Boc-Xaa-Aib-Yaa-OMe I-IV, (where Xaa = 4-F-Phe/NMeSer/Ile & Yaa = Tyr in peptide I-III respectively and Xaa = 4-F-Phe & Yaa = Ile in peptide IV) differing in terminal side chains. The solid state structural analysis reveals that tripeptide (I) displays supramolecular preference for double helical architecture. However, when slight modification has been introduced in the N-terminal side chains disfavour the double helical organisation (Peptide II and III). Indeed the peptides display sheet like ensemble within the framework. Besides replacement of C-terminal Tyr by Ile in peptide I even do not promote the architecture, emphasizing the dominant role of balance of side chains in stabilizing double helical organisation. The CD measurements, concentration dependant studies, NMR titrations and ROESY spectra are well in agreement with the solid state conformational investigation. Moreover the morphological experiments utilizing FE-SEM, support the heterogeneity present in the peptides. Thus this work may not only hold future promise in understanding the structure and function of neurodegenerative diseases but also assist in rational design of protein modification in biologically active peptides.

  6. D-amino acid-containing supramolecular nanofibers for potential cancer therapeutics.

    Science.gov (United States)

    Wang, Huaimin; Feng, Zhaoqianqi; Xu, Bing

    2017-02-01

    Nanostructures formed by peptides that self-assemble in water through non-covalent interactions have attracted considerable attention because peptides possess several unique advantages, such as modular design and easiness of synthesis, convenient modification with known functional motifs, good biocompatibility, low immunogenicity and toxicity, inherent biodegradability, and fast responses to a wide range of external stimuli. After about two decades of development, peptide-based supramolecular nanostructures have already shown great potentials in the fields of biomedicine. Among a range of biomedical applications, using such nanostructures for cancer therapy has attracted increased interests since cancer remains the major threat for human health. Comparing with L-peptides, nanostructures containing peptides made of D-amino acid (i.e., D-peptides) bear a unique advantage, biostability (i.e., resistance towards most of endogenous enzymes). The exploration of nanostructures containing D-amino acids, especially their biomedical applications, is still in its infancy. Herein we review the recent progress of D-amino acid-containing supramolecular nanofibers as an emerging class of biomaterials that exhibit unique features for the development of cancer therapeutics. In addition, we give a brief perspective about the challenges and promises in this research direction. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. A Supramolecular Sensing Platform for Phosphate Anions and an Anthrax Biomarker in a Microfluidic Device

    Directory of Open Access Journals (Sweden)

    Jurriaan Huskens

    2011-10-01

    Full Text Available A supramolecular platform based on self-assembled monolayers (SAMs has been implemented in a microfluidic device. The system has been applied for the sensing of two different analyte types: biologically relevant phosphate anions and aromatic carboxylic acids, which are important for anthrax detection. A Eu(III-EDTA complex was bound to β-cyclodextrin monolayers via orthogonal supramolecular host-guest interactions. The self-assembly of the Eu(III-EDTA conjugate and naphthalene β-diketone as an antenna resulted in the formation of a highly luminescent lanthanide complex on the microchannel surface. Detection of different phosphate anions and aromatic carboxylic acids was demonstrated by monitoring the decrease in red emission following displacement of the antenna by the analyte. Among these analytes, adenosine triphosphate (ATP and pyrophosphate, as well as dipicolinic acid (DPA which is a biomarker for anthrax, showed a strong response. Parallel fabrication of five sensing SAMs in a single multichannel chip was performed, as a first demonstration of phosphate and carboxylic acid screening in a multiplexed format that allows a general detection platform for both analyte systems in a single test run with µM and nM detection sensitivity for ATP and DPA, respectively.

  8. Supramolecular helical stacking of metallomesogens derived from enantiopure and racemic polycatenar oxazolines.

    Science.gov (United States)

    Barberá, Joaquín; Cavero, Emma; Lehmann, Matthias; Serrano, José-Luis; Sierra, Teresa; Vázquez, Jesús T

    2003-04-16

    The present report undertakes a challenge of general interest in supramolecular chemistry: the achievement of helical organizations with controlled structure. To achieve this target we considered the possibility of inducing supramolecular chirality using molecules that were designed to organize into columnar mesophases. The use of oxazoline-derived ligands and metal coordination served as tools to prepare molecules with a phasmidic-like structure, which show columnar organization in the liquid crystalline state. To ensure the formation of chiral mesophases, these complexes bear stereogenic centers in the rigid coordination environment of the metal. X-ray and circular dichroism experiments have revealed that chirality transfer does indeed take place from the chiral molecule to the columnar liquid crystal organization. This chiral columnar organization appears as a helix consisting of stacks of molecules that rotate with respect to one another along the column while maintaining their mean planes parallel to each other. In fact, it has been concluded that packing of these polycatenar molecules must be more efficient upon rotation of a molecule with respect to the adjacent one along the column. Furthermore, the same type of helical supraorganization has been found to be present in the mesophase of the racemic mixture and the mixture of diastereomers prepared from the racemic ligand. In this case, segregation of the optical isomers is proposed to occur to give rise to both types of helix (right-handed and left-handed).

  9. Elasticity-dependent fast underwater adhesion demonstrated by macroscopic supramolecular assembly.

    Science.gov (United States)

    Ju, Guannan; Cheng, Mengjiao; Guo, Fengli; Zhang, Qian; Shi, Feng

    2018-05-30

    Macroscopic supramolecular assembly (MSA) is a recent progress in supramolecular chemistry to associate visible building blocks through non-covalent interactions in a multivalent manner. Although various substrates (e. g. hydrogels, rigid materials) have been used, a general design rule of building blocks in MSA systems and interpretation of the assembly mechanism are still lacking and urgently in demand. Here we design three model systems with varied modulus and correlated the MSA probability with the elasticity. Based on the effects of substrate deformability on multivalency, we have proposed an elastic-modulus-dependent rule that building blocks below a critical modulus of 2.5 MPa can achieve MSA for the used host/guest system. Moreover, this MSA rule applies well to the design of materials applicable for fast underwater adhesion: Soft substrates (0.5 MPa) can achieve underwater adhesion within 10 s with one magnitude higher strength than that of rigid substrates (2.5 MPa). © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. A systematic structural study of halogen bonding versus hydrogen bonding within competitive supramolecular systems

    Directory of Open Access Journals (Sweden)

    Christer B. Aakeröy

    2015-09-01

    Full Text Available As halogen bonds gain prevalence in supramolecular synthesis and materials chemistry, it has become necessary to examine more closely how such interactions compete with or complement hydrogen bonds whenever both are present within the same system. As hydrogen and halogen bonds have several fundamental features in common, it is often difficult to predict which will be the primary interaction in a supramolecular system, especially as they have comparable strength and geometric requirements. To address this challenge, a series of molecules containing both hydrogen- and halogen-bond donors were co-crystallized with various monotopic, ditopic symmetric and ditopic asymmetric acceptor molecules. The outcome of each reaction was examined using IR spectroscopy and, whenever possible, single-crystal X-ray diffraction. 24 crystal structures were obtained and subsequently analyzed, and the synthon preferences of the competing hydrogen- and halogen-bond donors were rationalized against a background of calculated molecular electrostatic potential values. It has been shown that readily accessible electrostatic potentials can offer useful practical guidelines for predicting the most likely primary synthons in these co-crystals as long as the potential differences are weighted appropriately.

  11. Supramolecular order and structural dynamics: A STM study of 2H-tetraphenylporphycene on Cu(111)

    Energy Technology Data Exchange (ETDEWEB)

    Stark, Michael; Träg, Johannes; Ditze, Stefanie; Steinrück, Hans-Peter; Marbach, Hubertus, E-mail: hubertus.marbach@fau.de [Lehrstuhl für Physikalische Chemie II, Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058 Erlangen (Germany); Interdisciplinary Center for Molecular Materials (ICMM), Universität Erlangen-Nürnberg, Henkestr. 42, 91054 Erlangen (Germany); Brenner, Wolfgang; Jux, Norbert [Lehrstuhl für Organische Chemie II, Universität Erlangen-Nürnberg, Henkestr. 42, 91054 Erlangen (Germany)

    2015-03-14

    The adsorption of 2H-tetraphenylporphycene (2HTPPc) on Cu(111) was investigated by scanning tunneling microscopy (STM). At medium coverages, supramolecular ordered islands are observed. The individual 2HTPPc molecules appear as two pairs of intense protrusions which are separated by an elongated depression. In the islands, the molecules are organized in rows oriented along one of the close packed Cu(111) substrate rows; the structure is stabilized by T-type interactions of the phenyl substituents of neighboring molecules. Two types of rows are observed, namely, highly ordered rows in which all molecules exhibit the same orientation, and less ordered rows in which the molecules exhibit two perpendicular orientations. Altogether, three different azimuthal orientations of 2HTPPc are observed within one domain, all of them rotated by 15° ± 1° relative to one closed packed Cu direction. The highly ordered rows are always separated by either one or two less ordered rows, with the latter structure being the thermodynamically more stable one. The situation in the islands is highly dynamic, such that molecules in the less ordered rows occasionally change orientation, also complete highly ordered rows can move. The supramolecular order and structural dynamics are discussed on the basis of the specific molecule-substrate and molecule-molecule interactions.

  12. p/n-Polarity of thiophene oligomers in photovoltaic cells: role of molecular vs. supramolecular properties.

    Science.gov (United States)

    Ghosh, Tanwistha; Gopal, Anesh; Saeki, Akinori; Seki, Shu; Nair, Vijayakumar C

    2015-04-28

    Molecular and supramolecular properties play key roles in the optoelectronic properties and photovoltaic performances of organic materials. In the present work, we show how small changes in the molecular structure affect such properties, which in turn control the intrinsic and fundamental properties such as the p/n-polarity of organic semiconductors in bulk-heterojunction solar cells. Herein, we designed and synthesized two acceptor-donor-acceptor type semiconducting thiophene oligomers end-functionalized with oxazolone/isoxazolone derivatives (OT1 and OT2 respectively). The HOMO-LUMO energy levels of both derivatives were found to be positioned in such a way that they can act as electron acceptors to P3HT and electron donors to PCBM. However, OT1 functions as a donor (with PCBM) and OT2 as an acceptor (with P3HT) in BHJ photovoltaic cells, and their reverse roles results in either no or poor performance of the cells. Detailed studies using UV-vis absorption and fluorescence spectroscopy, time-correlated single photon counting, UV-photoelectron spectroscopy, density functional theory calculations, X-ray diffraction, and thermal gravimetric analysis proved that both molecular and supramolecular properties contributed equally but in a contrasting manner to the abovementioned observation. The obtained results were further validated by flash-photolysis time-resolved microwave conductivity studies which showed an excellent correlation between the structure, property, and device performances of the materials.

  13. Electrochemical aptasensor for highly sensitive determination of cocaine using a supramolecular aptamer and rolling circle amplification

    International Nuclear Information System (INIS)

    Shen, Bo; Yan, Yurong; Tang, Renkuan; Li, Yongguo; Li, Jianbo; Cheng, Wei; Ju, Huangxian; Ding, Shijia

    2015-01-01

    We report on a novel strategy for the electrochemical detection of cocaine. It is based on the use of a supramolecular aptamer, rolling circle amplification (RCA), and multiplex binding of a biotin-strepavidin system. The aptamer fragments were assembled to a supramolecular aptamer which, in the presence of cocaine, conjugates to streptavidin for anchoring of biotinylated circular DNA. This initiates RCA and enables sensitive electrochemical-enzymatic readout. A significant signal amplification was obtained by using streptavidin linked to alkaline phosphatase that binds to the remaining biotinylated detection probes and catalyzes the hydrolysis of the synthetic enzyme substrate α-naphthylphosphate. This dual amplification strategy tremendously increases the detection limit of the aptasensor. Under optimal conditions and using differential pulse voltammetry, cocaine can be detected in the concentration range between 2 and 500 nM with a detection limit as low as 1.3 nM (at S/N = 3). The method is specific and acceptably reproducible. It was successfully applied to the detection of cocaine in (spiked) urine samples. The data were in good agreement with those obtained by the GC-MS reference method. (author)

  14. Supramolecular Systems and Chemical Reactions in Single-Molecule Break Junctions.

    Science.gov (United States)

    Li, Xiaohui; Hu, Duan; Tan, Zhibing; Bai, Jie; Xiao, Zongyuan; Yang, Yang; Shi, Jia; Hong, Wenjing

    2017-04-01

    The major challenges of molecular electronics are the understanding and manipulation of the electron transport through the single-molecule junction. With the single-molecule break junction techniques, including scanning tunneling microscope break junction technique and mechanically controllable break junction technique, the charge transport through various single-molecule and supramolecular junctions has been studied during the dynamic fabrication and continuous characterization of molecular junctions. This review starts from the charge transport characterization of supramolecular junctions through a variety of noncovalent interactions, such as hydrogen bond, π-π interaction, and electrostatic force. We further review the recent progress in constructing highly conductive molecular junctions via chemical reactions, the response of molecular junctions to external stimuli, as well as the application of break junction techniques in controlling and monitoring chemical reactions in situ. We suggest that beyond the measurement of single molecular conductance, the single-molecule break junction techniques provide a promising access to study molecular assembly and chemical reactions at the single-molecule scale.

  15. A New Supramolecular Route for Using Rod-Coil Block Copolymers in Photovoltaic Applications

    Science.gov (United States)

    Mezzenga, Raffaele; Sary, Nicolas; Richard, Fanny; Brochon, Cyril; Leclerc, Nicolas; Leveque, Patrick; Audinot, Jean Nicolas; Heiser, Thomas; Hadziioannou, Georges; Berson, Solenn

    2010-03-01

    We propose a new supramolecular strategy to blend together rod-coil poly(3-hexylthiophene)-poly(4-vinylpyridine) (P3HTP4VP) block copolymers and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM). The P4VP and PCBM are mixed together by weak supramolecular interactions, and the resulting materials exhibit microphase separated morphologies of electron-donor and electron-acceptor rich domains. The microphase segregated P3HT-rod domains act as electron-donating species and the homogeneous P4VP block:PCBM blend acts as the electron-acceptor domain. We describe the photovoltaic performance of standard and inverted devices whose active layer is composed thereof and show the effect of finely engineering the interfacial properties of the active layer to obtain competitive photovoltaic performance with superior thermal stability. (1) N. Sary, F. Richard, C. Brochon, N. Leclerc, P. Leveque, JN Audinot, S. Berson, T. Heiser, G. Hadziioannou, R. Mezzenga, Adv. Mater. in Press (2010)

  16. Viscoelastic and fractal characteristics of a supramolecular hydrogel hybridized with clay nanoparticles.

    Science.gov (United States)

    Song, Fei; Zhang, Li-Ming; Shi, Jun-Feng; Li, Nan-Nan

    2010-12-01

    The supramolecular hydrogels derived from low-molecular-mass gelators represent a unique class of soft matters and have important potential applications in biomedical fields, separation technology and cosmetic science. However, they suffer usually from weak mechanical and viscoelastic properties. In this work, we carry out the in situ hybridization of clay nanoparticles (Laponite RD) into the supramolecular hydrogel formed from a low-molecular-mass hydrogelator, 2,6-di[N-(carboxyethyl carbonyl)amino]pyridine (DAP), and investigate the viscoelastic and structural characteristics of resultant hybrid hydrogel. It was found that a small concentration of Laponite RD could lead to a significant increase in the storage modulus, loss modulus or complex viscosity. Compared with neat DAP hydrogel, the hybrid hydrogel has a greater hydrogel strength and a lower relaxation exponent. In particular, the enhancement of the clay nanoparticles to the viscoelastic properties of the DAP hydrogel is more effective in the case of higher DAP concentration. By relating its macroscopic elastic properties to a scaling fractal model, such a hybrid hydrogel was confirmed to be in the strong-link regime and to have a more complex network structure with a higher fractal dimension when compared with neat DAP hydrogel. Copyright © 2010 Elsevier B.V. All rights reserved.

  17. An intelligent anticorrosion coating based on pH-responsive supramolecular nanocontainers

    International Nuclear Information System (INIS)

    Chen Tao; Fu Jiajun

    2012-01-01

    The hollow mesoporous silica nanoparticles (HMSNs), which have been used as the nanocontainers for the corrosion inhibitor, benzotriazole, were fabricated using the hard-template method. Alkaline-responsive HMSNs based on cucurbit[6]uril (CB[6])/bisammonium supramolecular complex and acid-responsive HMSNs based on α-cyclodextrin (α-CD)/aniline supramolecular complex, which operate in water, have been achieved and characterized by solid-state NMR, thermogravimetry analysis, scanning electron microscopy, transmission electron microscopy and N 2 adsorption-desorption analysis. The two elaborately designed nanocontainers show the pH-controlled encapsulation/release behaviors for benzotriazole molecules. Equal amounts of the alkaline- and acid-responsive nanocontainers were uniformly distributed in the hybrid zirconia-silica sol–gel coating and thus formed the intelligent anticorrosion coating. The self-healing property of AA2024 alloy coated with the intelligent anticorrosion coating is evaluated by electrochemical impedance spectroscopy (EIS). The sol–gel coating doped with the pH-responsive nanocontainers clearly demonstrates long-term corrosion protection performances when compared to the undoped sol–gel coating, which is attributed to the release of corrosion inhibitor from the nanocontainers after feeling the changes of environmental pH values near the corroded areas. (paper)

  18. Protein-based polymers that bond to DNA : design of virus-like particles and supramolecular nanostructures

    NARCIS (Netherlands)

    Hernandez Garcia, A.

    2014-01-01

    In this thesis it is demonstrated that it is possible to use Protein-based Polymers (PbPs) as synthetic binders of DNA (or any other negatively charged polyelectrolyte). The PbPs co-assemble with their DNA templates to form highly organized virus-like particles and supramolecular structures. A

  19. An eco-friendly in situ activatable antibiotic via cucurbit[8]uril-mediated supramolecular crosslinking of branched polyethylenimine.

    Science.gov (United States)

    Li, Shengke; Jiang, Nan; Zhao, Wenxuan; Ding, Yuan-Fu; Zheng, Ying; Wang, Lian-Hui; Zheng, Jun; Wang, Ruibing

    2017-05-30

    We report an unprecedented, eco-friendly, in situ activatable model antibiotic, phenylalanyl-polyethylenimine (PhePEI), to potentially diminish antibiotic pollution of the environment and associated antibiotic resistance. The inactive PhePEI can be reversibly activated upon supramolecular crosslinking by cucurbit[8]uril, conferring potent antibacterial activity.

  20. Self-assembly of a supramolecular square between [Ni(dppe(TOF2] and 4,4'-Bipyridine

    Directory of Open Access Journals (Sweden)

    Paulo Torres

    2013-08-01

    Full Text Available The main interest of this research is to contribute to the development and understanding of supramolecular chemistry and molecular architectures, which are constructed by the self-assembly of supramolecular entities. Therefore, the synthesis and characterization (IR, UV, 1H NMR, 31P, 19F, 1H-1H COSY of a nickel (II supramolecular square [7] was performed through the synthesis between nickel chloride [1] and diphenylphosphinoethane (dppe [2] to form the precursor complex [Ni(dppeCl2] [3]. This was followed by the synthesis of the complex of interest, [Ni(dppe(TOF2] [5], using the precursor and silver trifluoromethanesulfonate (Ag-TOF. Finally, the self-assembly was performed between the complex [1,2-bis(diphenylphosphinoethanebistriflatonickel(II] [Ni(dppe(OSO2CF32] [5] and the organic ligand 4,4'-bipyridine [6], which act as vertex and edge, respectively.According to various analyses, it was found that the self-assembly generated only one supramolecular species; a square is the most probable thermodynamic structure.

  1. Effect of H-bonding on order amplification in the growth of a supramolecular polymer in water

    NARCIS (Netherlands)

    Garzoni, M.; Baker, M.B.; Leenders, C.M.A.; Voets, I.K.; Albertazzi, Lorenzo; Palmans, A.R.A.; Meijer, E.W.; Pavan, G.M.

    2016-01-01

    While a great deal of knowledge on the roles of hydrogen bonding and hydrophobicity in proteins has resulted in the creation of rationally designed and functional peptidic structures, the roles of these forces on purely synthetic supramolecular architectures in water have proven difficult to

  2. Asymmetric noncovalent synthesis of self-assembled one-dimensional stacks by a chiral supramolecular auxiliary approach

    NARCIS (Netherlands)

    George, S.J.; Tomovic, Z.; Averbeke, Van B.; Beljonne, D.; Lazzaroni, R.; Schenning, A.P.H.J.; Meijer, E.W.

    2012-01-01

    Stereoselective noncovalent synthesis of one-dimensional helical self-assembled stacks of achiral oligo(p-phenylenevinylene) ureidotriazine (AOPV3) monomers is obtained by a chiral supramolecular auxiliary approach. The racemic mixture of helical stacks of achiral AOPV3 molecules is converted into

  3. Thermoresponsive Supramolecular Chemotherapy by "V"-Shaped Armed β-Cyclodextrin Star Polymer to Overcome Drug Resistance.

    Science.gov (United States)

    Fan, Xiaoshan; Cheng, Hongwei; Wang, Xiaoyuan; Ye, Enyi; Loh, Xian Jun; Wu, Yun-Long; Li, Zibiao

    2018-04-01

    Pump mediated drug efflux is the key reason to result in the failure of chemotherapy. Herein, a novel star polymer β-CD-v-(PEG-β-PNIPAAm) 7 consisting of a β-CD core, grafted with thermo-responsive poly(N-isopropylacrylamide) (PNIPAAm) and biocompatible poly(ethylene glycol) (PEG) in the multiple "V"-shaped arms is designed and further fabricated into supramolecular nanocarriers for drug resistant cancer therapy. The star polymer could encapsulate chemotherapeutics between β-cyclodextrin and anti-cancer drug via inclusion complex (IC). Furthermore, the temperature induced chain association of PNIPAAm segments facilitated the IC to form supramolecular nanoparticles at 37 °C, whereas the presence of PEG impart great stability to the self-assemblies. When incubated with MDR-1 membrane pump regulated drug resistant tumor cells, much higher and faster cellular uptake of the supramolecular nanoparticles were detected, and the enhanced intracellular retention of drugs could lead to significant inhibition of cell growth. Further in vivo evaluation showed high therapeutic efficacy in suppressing drug resistant tumor growth without a significant impact on the normal functions of main organs. This work signifies thermo-responsive supramolecular chemotherapy is promising in combating pump mediated drug resistance in both in vitro and in vivo models, which may be encouraging for the advanced drug delivery platform design to overcome drug resistant cancer. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Supramolecular architectures in layer-by-layer films of single-walled carbon nanotubes, chitosan and cobalt (II) phthalocyanine

    International Nuclear Information System (INIS)

    Sousa Luz, Roberto A. de; Martins, Marccus Victor A.; Magalhaes, Janildo L.; Siqueira, Jose R.; Zucolotto, Valtencir; Oliveira, Osvaldo N.; Crespilho, Frank N.; Cantanhede da Silva, Welter

    2011-01-01

    Highlights: → Platforms were assembled from cobalt phthalocyanine, chitosan and carbon nanotubes. → Supramolecular organization of multilayer films was investigated. → Increase of the supramolecular charge transfer after carbon nanotube incorporation. → Functional modulation based on constitutional dynamic chemistry was achieved. - Abstract: The building of supramolecular structures in nanostructured films has been exploited for a number of applications, with the film properties being controlled at the molecular level. In this study, we report on the layer-by-layer (LbL) films combining cobalt (II) tetrasulfonated phthalocyanine (CoTsPc), chitosan (Chit) and single-walled carbon nanotubes (SWCNTs) in two architectures, {Chit/CoTsPc} n and {Chit-SWCNTs/CoTsPc} n (n = 1-10). The physicochemical properties of the films were evaluated and the multilayer formation was monitored with microgravimetry measurements using a quartz microbalance crystal and an electrochemical technique. According to atomic force microscopy (AFM) results, the incorporation of SWCNTs caused the films to be thicker, with a thickness ca. 3 fold that of a 2-bilayer LbL film with no SWCNTs. Cyclic voltammetry revealed a quasi-reversible, one electron process with E 1/2 at -0.65 V (vs SCE) and an irreversible oxidation process at 0.80 V in a physiological medium for both systems, which can be attributed to [CoTsPc(I)] 5- /[CoTsPc(II)] 4- and CoTsPc(II) to CoTsPc(III), respectively. The {Chit-SWCNTs/CoTsPc} 5 multilayer film exhibited an increased faradaic current, probably associated with the supramolecular charge transfer interaction between cobalt phthalocyanine and SWCNTs. The results demonstrate that an intimate contact at the supramolecular level between functional SWCNTs immobilized into biocompatible chitosan polymer and CoTsPc improves the electron flow from CoTsPc redox sites to the electrode surface.

  5. Control over Structure and Function of Peptide Amphiphile Supramolecular Assemblies through Molecular Design and Energy Landscapes

    Science.gov (United States)

    Tantakitti, Faifan

    Supramolecular chemistry is a powerful tool to create a material of a defined structure with tunable properties. This strategy has led to catalytically active, bioactive, and environment-responsive materials, among others, that are valuable in applications ranging from sensor technology to energy and medicine. Supramolecular polymers formed by peptide amphiphiles (PAs) have been especially relevant in tissue regeneration due to their ability to form biocompatible structures and mimic many important signaling molecules in biology. These supramolecular polymers can form nanofibers that create networks which mimic natural extracellular matrices. PA materials have been shown to induce growth of blood vessels, bone, cartilage, and nervous tissue, among others. The work described in this thesis not only studied the relationship between molecular structure and functions of PA assemblies, but also uncovered a powerful link between the energy landscape of their supramolecular self-assembly and the ability of PA materials to interact with cells. In chapter 2, it is argued that fabricating fibrous nanostructures with defined mechanical properties and decoration with bioactive molecules is not sufficient to create a material that can effectively communicate with cells. By systemically placing the fibronectin-derived RGDS epitope at increasing distances from the surface of PA nanofibers through a linker of one to five glycine residues, integrin-mediated RGDS signaling was enhanced. The results suggested that the spatial presentation of an epitope on PA nanofibers strongly influences the bioactivity of the PA substrates. In further improving functionality of a PA-based scaffold to effectively direct cell growth and differentiation, chapter 3 explored the use of a cell microcarrier to compartmentalize and simultaneously tune insoluble and soluble signals in a single matrix. PA nanofibers were incorporated at the surface of the microcarrier in order to promote cell adhesion, while

  6. The crystal structures of three pyrazine-2,5-dicarboxamides: three-dimensional supramolecular structures

    Directory of Open Access Journals (Sweden)

    Dilovan S. Cati

    2017-05-01

    Full Text Available The complete molecules of the title compounds, N2,N5-bis(pyridin-2-ylmethylpyrazine-2,5-dicarboxamide, C18H16N6O2 (I, 3,6-dimethyl-N2,N5-bis(pyridin-2-ylmethylpyrazine-2,5-dicarboxamide, C20H20N6O2 (II, and N2,N5-bis(pyridin-4-ylmethylpyrazine-2,5-dicarboxamide, C18H16N6O2 (III, are generated by inversion symmetry, with the pyrazine rings being located about centres of inversion. Each molecule has an extended conformation with the pyridine rings inclined to the pyrazine ring by 89.17 (7° in (I, 75.83 (8° in (II and by 82.71 (6° in (III. In the crystal of (I, molecules are linked by N—H...N hydrogen bonds, forming layers lying parallel to the bc plane. The layers are linked by C—H...O hydrogen bonds, forming a three-dimensional supramolecular structure. In the crystal of (II, molecules are also linked by N—H...N hydrogen bonds, forming layers lying parallel to the (10-1 plane. As in (I, the layers are linked by C—H...O hydrogen bonds, forming a three-dimensional supramolecular structure. In the crystal of (III, molecules are again linked by N—H...N hydrogen bonds, but here form corrugated sheets lying parallel to the bc plane. Within the sheets, neighbouring pyridine rings are linked by offset π–π interactions [intercentroid distance = 3.739 (1 Å]. The sheets are linked by C—H...O hydrogen bonds, forming a three-dimensional supramolecular structure. Compound (I crystallizes in the monoclinic space group P21/c. Another monoclinic polymorph, space group C2/c, has been reported on by Cockriel et al. [Inorg. Chem. Commun. (2008, 11, 1–4]. The molecular structures of the two polymorphs are compared.

  7. Supramolecular structure of a perylene derivative in thin films made by vacuum thermal evaporation

    International Nuclear Information System (INIS)

    Fernandes, Jose Diego

    2015-01-01

    The supramolecular arrangement of organic thin films is a factor that influences both optical and electrical properties of these films and, consequently, the technological applications involving organic electronics. In this dissertation, thin films of a perylene derivative (bis butylimido perylene, acronym BuPTCD) were produced by physical vapor deposition (PVD) using vacuum thermal evaporation. The aim of this work was to investigate the supramolecular arrangement of BuPTCD films, which implies to control the thickness at nanometer scale and to determine the molecular organization, the morphology (at nano and micrometer scales) and the crystallinity, besides the stability of this arrangement as a function of the temperature. Optical properties (such as absorption and emission) and electrical properties (such as conductivity and photoconductivity) were also determined. The UV-Vis absorption spectra revealed a controlled growth (uniform) of the BuPTCD films. Atomic force and optical microscopy images showed a homogeneous surface of the film at nano and micrometer scales, respectively. The X-ray diffraction showed that the BuPTCD powder and PVD film have different crystalline structures, with the BuPTCD molecules head-on oriented in the PVD films, supported on the substrate surface by the side group (FTIR). This structure favors the light emission (photoluminescence) by the formation of excimers. The thermal treatment (200°C for 10 min) does not affect the molecular organization of the PVD films, showing a thermal stability of the BuPTCD supramolecular arrangement under these circumstances. The electrical measurements (DC) showed a linear increase of the current as a function of the tension, which is characteristic of ohmic behavior. Also, the films exhibited an increase of current by 2 orders of magnitude when exposed to light (photoconductive properties). Finally, BuPTCD films were exposed to vapor of trifluoroacetic acid (TFA) to verify the sensitivity of the Bu

  8. Supramolecular assembled three-dimensional graphene hybrids: Synthesis and applications in supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Ni, Lubin [College of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002, Jiangsu (China); Zhang, Wang [College of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002, Jiangsu (China); Graduate School of Convergence Science and Technology, Seoul National University, Seoul, 151-742 (Korea, Republic of); Wu, Zhen; Sun, Chunyu; Cai, Yin; Yang, Guang; Chen, Ming [College of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002, Jiangsu (China); Piao, Yuanzhe, E-mail: parkat9@snu.ac.kr [Graduate School of Convergence Science and Technology, Seoul National University, Seoul, 151-742 (Korea, Republic of); Diao, Guowang, E-mail: gwdiao@yzu.edu.cn [College of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002, Jiangsu (China)

    2017-02-28

    Graphical abstract: Supramolecular assembled three-dimensdional graphene-based architectures were built by host-guest interactions of β-cyclodextrin polymers(β-CDPs) with adamantine end-capped poly(ethylene oxide) polymer linker (PEG-AD), exhibit significantly improved electrochemical performances of supercapacitor in terms of high specific capacitance, remarkable rate capability, and excellent cycling stability compared to pristine reduced graphene oxide. - Highlights: • Supramolecular assembled three-Dimensional (3D) graphene was first fabricated by host-guest interactions of β-CDPs with PEG-AD linkers. • The incorporation of PEG-AD linker into rGO sheets can provide efficient 3D electron transfer pathways and ion diffusion channels. • The 3D self-assembled graphene exhibits high specific capacitance, remarkable rate capability, and excellent cycling stability. • This study shed new lights to design 3D self-assembled graphene materials and their urgent applications in energy storage. - Abstract: Graphene-based materials have received worldwide attention in the focus of forefront energy storage investigations. Currently, the design of novel three-dimensional (3D) graphene structures with high energy capability, superior electron and ion conductivity, and robust mechanical flexibility is still a great challenge. Herein, we have successfully demonstrated a novel approach to fabricate 3D assembled graphene through the supramolecular interactions of β-cyclodextrin polymers (β-CDP) with an adamantine end-capped poly(ethylene oxide) polymer linker (PEG-AD). The incorporation of PEG-AD linker into rGO sheets increased the interlayer spacing of rGO sheets to form 3D graphene materials, which can provide efficient 3D electron transfer pathways and ion diffusion channels, and facilitate the infiltration of gel electrolyte. The as-prepared 3D self-assembled graphene materials exhibit significantly improved electrochemical performances of supercapacitor in terms

  9. Investigation of supramolecular synthons and structural characterisation of aminopyridine-carboxylic acid derivatives.

    Science.gov (United States)

    Hemamalini, Madhukar; Loh, Wan-Sin; Quah, Ching Kheng; Fun, Hoong-Kun

    2014-01-01

    Co-crystal is a structurally homogeneous crystalline material that contains two or more neutral building blocks that are present in definite stoichiometric amounts. The main advantage of co-crystals is their ability to generate a variety of solid forms of a drug that have distinct physicochemical properties from the solid co-crystal components. In the present investigation, five co-crystals containing 2-amino-6-chloropyridine (AMPY) moiety were synthesized and characterized. The crystal structure of 2-amino-6-chloropyridine (AMPY) (I), and the robustness of pyridine-acid supramolecular synthon were discussed in four stoichiometry co-crystals of AMPY…BA (II), AMPY…2ABA (III), AMPY…3CLBA (IV) and AMPY…4NBA (V). The abbreviated designations used are benzoic acid (BA), 2-aminobenzoic acid (2ABA), 3-chlorobenzoic acid (3CLBA) and 4-nitrobenzoic acid (4NBA). All the crystalline materials have been characterized by (1)HNMR, (13)CNMR, IR, photoluminescence, TEM analysis and X-ray diffraction. The supramolecular assembly of each co-crystal is analyzed and discussed. Extensive N---H · · · N/N---H · · · O/O---H · · · N hydrogen bonds are found in (I-V), featuring different supramolecular synthons. In the crystal structure, for compound (I), the 2-amino-6-chloropyridine molecules are linked together into centrosymmetric dimers by hydrogen bonds to form homosynthon, whereas for compounds (II-V), the carboxylic group of the respective acids (benzoic acid, 2-aminobenzoic acid, 3-chlorobenzoic acid and 4-nitrobenzoic acid) interacts with pyridine molecule in a linear fashion through a pair of N---H · · · O and O---H · · · N hydrogen bonds, generating cyclic hydrogen-bonded motifs with the graph-set notation [Formula: see text] , to form heterosynthon. In compound (II), another intermolecular N---H · · · O hydrogen bonds further link these heterosynthons into zig-zag chains. Whereas in compounds (IV) and (V

  10. Supramolecular assembled three-dimensional graphene hybrids: Synthesis and applications in supercapacitors

    International Nuclear Information System (INIS)

    Ni, Lubin; Zhang, Wang; Wu, Zhen; Sun, Chunyu; Cai, Yin; Yang, Guang; Chen, Ming; Piao, Yuanzhe; Diao, Guowang

    2017-01-01

    Graphical abstract: Supramolecular assembled three-dimensdional graphene-based architectures were built by host-guest interactions of β-cyclodextrin polymers(β-CDPs) with adamantine end-capped poly(ethylene oxide) polymer linker (PEG-AD), exhibit significantly improved electrochemical performances of supercapacitor in terms of high specific capacitance, remarkable rate capability, and excellent cycling stability compared to pristine reduced graphene oxide. - Highlights: • Supramolecular assembled three-Dimensional (3D) graphene was first fabricated by host-guest interactions of β-CDPs with PEG-AD linkers. • The incorporation of PEG-AD linker into rGO sheets can provide efficient 3D electron transfer pathways and ion diffusion channels. • The 3D self-assembled graphene exhibits high specific capacitance, remarkable rate capability, and excellent cycling stability. • This study shed new lights to design 3D self-assembled graphene materials and their urgent applications in energy storage. - Abstract: Graphene-based materials have received worldwide attention in the focus of forefront energy storage investigations. Currently, the design of novel three-dimensional (3D) graphene structures with high energy capability, superior electron and ion conductivity, and robust mechanical flexibility is still a great challenge. Herein, we have successfully demonstrated a novel approach to fabricate 3D assembled graphene through the supramolecular interactions of β-cyclodextrin polymers (β-CDP) with an adamantine end-capped poly(ethylene oxide) polymer linker (PEG-AD). The incorporation of PEG-AD linker into rGO sheets increased the interlayer spacing of rGO sheets to form 3D graphene materials, which can provide efficient 3D electron transfer pathways and ion diffusion channels, and facilitate the infiltration of gel electrolyte. The as-prepared 3D self-assembled graphene materials exhibit significantly improved electrochemical performances of supercapacitor in terms

  11. Supramolecular assembly of borate with quaternary ammonium: Crystal structure and tunable luminescent properties

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Jie; Wang, Yong-gang [Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China); Wang, Ying-xia, E-mail: wangyx@pku.edu.cn [Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China); Liao, Fu-hui [Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China); Lin, Jian-hua, E-mail: jhlin@pku.edu.cn [Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China)

    2013-04-15

    A new borate [C{sub 6}H{sub 16}N][B{sub 5}O{sub 6}(OH){sub 4}] (1) is synthesized hydrothermally by the reaction of isopropyltrimethylammonium hydroxide with boric acid. It crystallizes in the triclinic space group P-1 with the parameters a=9.1578(10) Å, b=9.372(9) Å, c=9.9812(10) Å, α=66.508(2)°, β=74.751(2)°, γ=81.893(2)°. The [B{sub 5}O{sub 6}(OH){sub 4}]{sup −} anions are interlinked via hydrogen bonding forming a 3D supramolecular network containing large cavities, where reside the (CH{sub 3}){sub 3}(i-C{sub 3}H{sub 7}) N{sup +} cations. This borate shows tunable luminescent properties with temperature, heating-treatment, exciting-light, and solvents. The fluorescent intensity of 1 enhances 6-fold with decreasing the temperature from 25 K to 78 K. By treatment under different temperatures, the luminescence of 1 shifted from blue to white and the sample treated at 230 °C emits bright white light to naked eyes. The hybrid borate can disperse in different solvents, and shows a red-shifted and intense emission in polar solvents. - Graphical abstract: The new quaternary ammonium borate [C{sub 6}H{sub 17}N][B{sub 5}O{sub 6}(OH){sub 4}] contains a 3D supramolecular network formed by hydrogen bond linked [B{sub 5}O{sub 6}(OH){sub 4}]{sup −} anions and shows tunable luminescent properties with temperature, excitation light, and solvents. Highlights: ► A novel quaternary ammonium borate was synthesized. ► It possesses a supramolecular network fomed by H-bonded [B{sub 5}O{sub 6}(OH){sub 4}]{sup −} anions. ► This borate shows tunable luminescent properties with temperature, heating treatment, excitation light, and solvents.

  12. Supramolecular Self-Assembly of Histidine-Capped-Dialkoxy-Anthracene: A Visible Light Triggered Platform for facile siRNA Delivery

    KAUST Repository

    Patil, Sachin; Moosa, Basem; Alsaiari, Shahad; Alamoudi, Kholod; Alshamsan, Aws; Almailk, Abdulaziz; Adil, Karim; Eddaoudi, Mohamed; Khashab, Niveen M.

    2016-01-01

    Supramolecular self-assembly of histidine-capped-dialkoxy-anthracene (HDA) results in the formation of light responsive nanostructures.Single-crystal X-ray diffraction analysis of HDA shows two types of hydrogen bonding. The first hydrogen bond

  13. Self-assembling graphene-anthraquinone-2-sulphonate supramolecular nanostructures with enhanced energy density for supercapacitors

    Science.gov (United States)

    Gao, Lifang; Gan, Shiyu; Li, Hongyan; Han, Dongxue; Li, Fenghua; Bao, Yu; Niu, Li

    2017-07-01

    Boosting the energy density of capacitive energy storage devices remains a crucial issue for facilitating applications. Herein, we report a graphene-anthraquinone supramolecular nanostructure by self-assembly for supercapacitors. The sulfonated anthraquinone exhibits high water solubility, a π-conjugated structure and redox active features, which not only serve as a spacer to interact with and stabilize graphene but also introduce extra pseudocapacitance contributions. The formed nest-like three-dimensional (3D) nanostructure with further hydrothermal treatment enhances the accessibility of ion transfer and exposes the redox-active quinone groups in the electrolytes. A fabricated all-solid-state flexible symmetric device delivers a high specific capacitance of 398.5 F g-1 at 1 A g-1 (1.5 times higher than graphene), superior energy density (52.24 Wh kg-1 at about 1 kW kg-1) and good stability (82% capacitance retention after 10 000 cycles).

  14. Interpenetrated Binary Supramolecular Nanofibers for Sensitive Fluorescence Detection of Six Classes of Explosives.

    Science.gov (United States)

    Xiong, Wei; Zhu, Qijian; Gong, Yanjun; Wang, Chen; Che, Yanke; Zhao, Jincai

    2018-04-03

    In this work, we develop a sequential self-assembly approach to fabricate interpenetrated binary supramolecular nanofibers consisting of carbazole oligomer 1-cobalt(II) (1-Co 2+ ) coordination nanofibers and oligomer 2 nanofibers for the sensitive detection of six classes of explosives. When exposed to peroxide explosives (e.g., H 2 O 2 ), Co 2+ in 1-Co 2+ coordination nanofibers can be reduced to Co + that can transfer an electron to the excited 2 nanofibers and thereby quench their fluorescence. On the other hand, when exposed to the other five classes of explosives, the excited 2 nanofibers can transfer an electron to explosives to quench their fluorescence. On the basis of the distinct fluorescence quenching mechanisms, six classes of explosives can be sensitively detected. Herein, we provide a new strategy to design broad-band fluorescence sensors for a rich identification of threats.

  15. Three-dimensional supramolecular architecture in imidazolium hydrogen 2,3,5,6-tetrafluoroterephthalate.

    Science.gov (United States)

    Yu, Li-Li; Cheng, Mei-Ling; Liu, Qi; Zhang, Zhi-Hui; Chen, Qun

    2010-04-01

    The asymmetric unit of the title salt formed between 2,3,5,6-tetrafluoroterephthalic acid (H(2)tfbdc) and imidazolium (ImH), C(3)H(5)N(2)(+).C(8)HF(4)O(4)(-), contains one Htfbdc(-) anion and one ImH(2)(+) cation, joined by a classical N-H...O hydrogen bond. The acid and base subunits are further linked by N-H...O and O-H...O hydrogen bonds into infinite two-dimensional layers with R(6)(5)(32) hydrogen-bond motifs. The resulting (4,4) network layers interpenetrate to produce an interlocked three-dimensional structure. The final three-dimensional supramolecular architecture is further stabilized by the linkages of two C-H...O interactions.

  16. Functional organic materials based on polymerized liquid-crystal monomers: supramolecular hydrogen-bonded systems.

    Science.gov (United States)

    Broer, Dirk J; Bastiaansen, Cees M W; Debije, Michael G; Schenning, Albertus P H J

    2012-07-16

    Functional organic materials are of great interest for a variety of applications. To obtain precise functional properties, well-defined hierarchically ordered supramolecular materials are crucial. The self-assembly of liquid crystals has proven to be an extremely useful tool in the development of well-defined nanostructured materials. We have chosen the illustrative example of photopolymerizable hydrogen-bonding mesogens to show that a wide variety of functional materials can be made from a relatively simple set of building blocks. Upon mixing these compounds with other reactive mesogens, nematic, chiral nematic, and smectic or columnar liquid-crystalline phases can be formed that can be applied as actuators, sensors and responsive reflectors, and nanoporous membranes, respectively. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Dynamic Softening or Stiffening a Supramolecular Hydrogel by Ultraviolet or Near-Infrared Light.

    Science.gov (United States)

    Zheng, Zhao; Hu, Jingjing; Wang, Hui; Huang, Junlin; Yu, Yihua; Zhang, Qiang; Cheng, Yiyun

    2017-07-26

    The development of light-responsive hydrogels that exhibit switchable size and mechanical properties with temporal and spatial resolution is of great importance in many fields. However, it remains challenging to prepare smart hydrogels that dramatically change their properties in response to both ultraviolet (UV) and near-infrared (NIR) lights. Here, we designed a dual-light responsive supramolecular gel by integrating UV light-switchable host-guest recognition, temperature responsiveness, and NIR photothermal ability in the gel. The gel could rapidly self-heal and is capable of both softening and stiffening controlled by UV and NIR lights, respectively. Besides stiffness modulation, the bending direction of the gel can be controlled by UV or NIR light irradiation. The smart gel makes it possible to generate dynamic materials that respond to both UV and NIR lights and represents a useful tool that might be used to modulate cellular microenvironments with spatiotemporal resolution.

  18. Supramolecular domains in mixed peptide self-assembled monolayers on gold nanoparticles.

    Science.gov (United States)

    Duchesne, Laurence; Wells, Geoff; Fernig, David G; Harris, Sarah A; Lévy, Raphaël

    2008-09-01

    Self-organization in mixed self-assembled monolayers of small molecules provides a route towards nanoparticles with complex molecular structures. Inspired by structural biology, a strategy based on chemical cross-linking is introduced to probe proximity between functional peptides embedded in a mixed self-assembled monolayer at the surface of a nanoparticle. The physical basis of the proximity measurement is a transition from intramolecular to intermolecular cross-linking as the functional peptides get closer. Experimental investigations of a binary peptide self-assembled monolayer show that this transition happens at an extremely low molar ratio of the functional versus matrix peptide. Molecular dynamics simulations of the peptide self-assembled monolayer are used to calculate the volume explored by the reactive groups. Comparison of the experimental results with a probabilistic model demonstrates that the peptides are not randomly distributed at the surface of the nanoparticle, but rather self-organize into supramolecular domains.

  19. Assembly of three organic–inorganic hybrid supramolecular materials based on reduced molybdenum(V) phosphates

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, He [Key Laboratory for Photonic and Electronic Bandgap Materials, Ministry of Education, School of Chemistry and Chemical Engineering, Harbin Normal University, Harbin 150025 (China); Key Laboratory of Synthesis of Functional Materials and Green Catalysis, Colleges of Heilongjiang Province, Harbin Normal University, Harbin 150025 (China); Yu, Kai, E-mail: hlyukai188@163.com [Key Laboratory for Photonic and Electronic Bandgap Materials, Ministry of Education, School of Chemistry and Chemical Engineering, Harbin Normal University, Harbin 150025 (China); Key Laboratory of Synthesis of Functional Materials and Green Catalysis, Colleges of Heilongjiang Province, Harbin Normal University, Harbin 150025 (China); Lv, Jing-Hua; Wang, Chun-Mei; Wang, Chun-Xiao [Key Laboratory for Photonic and Electronic Bandgap Materials, Ministry of Education, School of Chemistry and Chemical Engineering, Harbin Normal University, Harbin 150025 (China); Key Laboratory of Synthesis of Functional Materials and Green Catalysis, Colleges of Heilongjiang Province, Harbin Normal University, Harbin 150025 (China); Zhou, Bai-Bin, E-mail: zhou_bai_bin@163.com [Key Laboratory for Photonic and Electronic Bandgap Materials, Ministry of Education, School of Chemistry and Chemical Engineering, Harbin Normal University, Harbin 150025 (China); Key Laboratory of Synthesis of Functional Materials and Green Catalysis, Colleges of Heilongjiang Province, Harbin Normal University, Harbin 150025 (China)

    2014-09-15

    Three supramolecular materials based on (P{sub 4}Mo{sub 6}) polyoxoanions, (Hbbi){sub 2}(H{sub 2}bbi)[Cu{sub 3}Mo{sub 12}{sup V}O{sub 24}(OH){sub 6}(H{sub 2}O){sub 6}(HPO{sub 4}){sub 4}(H{sub 2}PO{sub 4}){sub 2}(PO{sub 4}){sub 2}]·3H{sub 2}O (1), (Hbbi){sub 2}(H{sub 2}bbi)[Ni{sub 3}Mo{sub 12}{sup V}O{sub 24}(OH){sub 6}(H{sub 2}O){sub 2}(HPO{sub 4}){sub 4}(H{sub 2}PO{sub 4}){sub 2}(PO{sub 4}){sub 2}]·9H{sub 2}O (2), (Hbpy)(bpy){sub 3}[Ni{sub 2}(H{sub 2}O){sub 10}Na(PCA){sub 2}][NiMo{sub 12}{sup V}O{sub 24}(OH){sub 6}(H{sub 2}PO{sub 4}){sub 6}(PO{sub 4}){sub 2}]·6H{sub 2}O (3) (bbi=1,1′-(1,4-butanediyl)bis(imidazole), bpy=4,4′-bipyridine, PCA=pyridine-4-carboxylic acid), have been hydrothermally synthesized and structurally characterized by the elemental analysis, TG, IR, UV–vis, PXRD and the single-crystal X-ray diffraction. Compounds 1 and 2 exhibit covalent 1-D chains constructed from M[P{sub 4}Mo{sub 6}]{sub 2} dimeric cluster and (M(H{sub 2}O){sub n}) (M=Cu, n=3 for 1 and M=Ni, n=1 for 2) linker. Compound 3 possesses an unusual POMMOF supramolecular layers based on [Ni(P{sub 4}Mo{sub 6})]{sub 2} dimeric units and 1-D metal–organic strings [Ni(H{sub 2}O){sub 5}Na(PCA)]{sub n}, in which an in situ ligand of PCA from 1,3-bis(4-pyridyl)propane (bpp) precursor was observed. Furthermore, the electrochemical behavior of 1–3-CPE and magnetic properties of 1–3 have been investigated in detail. - Graphical abstract: As new linking unit, Cu(H{sub 2}O){sub 3}, Ni(H{sub 2}O), and (Ni{sub 2}(H{sub 2}O){sub 10}Na(PCA){sub 2}) are introduced into (TM(P{sub 4}Mo{sub 6}){sub 2}) reaction systems to assemble three supramolecular materials under hydrothermal conditions via changing organic ligand and transition metal. - Highlights: • Tree new supramolecular hybrids based on (P{sub 4}Mo{sub 6}) cluster are reported. • Cu(H{sub 2}O){sub 3} and Ni(H{sub 2}O) as linker are introduced into the (TM(P{sub 4}Mo{sub 6}){sub 2}) systems. • 3 shows unusual layers based on

  20. Tunable blue organic light emitting diode based on aluminum calixarene supramolecular complex

    Science.gov (United States)

    Legnani, C.; Reyes, R.; Cremona, M.; Bagatin, I. A.; Toma, H. E.

    2004-07-01

    In this letter, the results of supramolecular organic light emitting diodes using a calix[4] arene complex thin film as emitter and electron transporting layer are presented. The devices were grown onto glass substrates coated with indium-tin-oxide layer and aluminum thick (150nm) cathode. By applying a dc voltage between the device electrodes in forward bias condition, a blue light emission in the active area of the device was observed. It was found that the electroluminescent emission peak can be tuned between 470 and 510nm changing the applied voltage bias from 4.3 to 5.4V. The observed tunable emission can be associated with an energy transfer from the calixarene compound.

  1. Printable optical sensors based on H-bonded supramolecular cholesteric liquid crystal networks.

    Science.gov (United States)

    Herzer, Nicole; Guneysu, Hilal; Davies, Dylan J D; Yildirim, Derya; Vaccaro, Antonio R; Broer, Dirk J; Bastiaansen, Cees W M; Schenning, Albertus P H J

    2012-05-09

    A printable H-bonded cholesteric liquid crystal (CLC) polymer film has been fabricated that, after conversion to a hygroscopic polymer salt film, responds to temperature and humidity by changing its reflection color. Fast-responding humidity sensors have been made in which the reflection color changes between green and yellow depending on the relative humidity. The change in reflection band is a result of a change in helix pitch in the film due to absorption and desorption of water, resulting in swelling/deswelling of the film material. When the polymer salt was saturated with water, a red-reflecting film was obtained that can potentially act as a time/temperature integrator. Finally, the films were printed on a foil, showing the potential application of supramolecular CLC materials as low-cost, printable, battery-free optical sensors.

  2. Functionalized Nanostructures: Redox-Active Porphyrin Anchors for Supramolecular DNA Assemblies

    KAUST Repository

    Börjesson, Karl

    2010-09-28

    We have synthesized and studied a supramolecular system comprising a 39-mer DNA with porphyrin-modified thymidine nucleosides anchored to the surface of large unilamellar vesicles (liposomes). Liposome porphyrin binding characteristics, such as orientation, strength, homogeneity, and binding site size, was determined, suggesting that the porphyrin is well suited as a photophysical and redox-active lipid anchor, in comparison to the inert cholesterol anchor commonly used today. Furthermore, the binding characteristics and hybridization capabilities were studied as a function of anchor size and number of anchoring points, properties that are of importance for our future plans to use the addressability of these redox-active nodes in larger DNA-based nanoconstructs. Electron transfer from photoexcited porphyrin to a lipophilic benzoquinone residing in the lipid membrane was characterized by steady-state and time-resolved fluorescence and verified by femtosecond transient absorption. © 2010 American Chemical Society.

  3. Competitive Self-Assembly Manifests Supramolecular Darwinism in Soft-Oxometalates

    Science.gov (United States)

    Das, Santu; Kumar, Saurabh; Mallick, Apabrita; Roy, Soumyajit

    2015-09-01

    Topological transformation manifested in inorganic materials shows manifold possibilities. In our present work, we show a clear topological transformation in a soft-oxometalate (SOM) system which was formed from its polyoxometalate (POM) precursor [PMo12@Mo72Fe30]. This topological transformation was observed due to time dependent competitive self-assembly of two different length scale soft-oxometalate moieties formed from this two-component host-guest reaction. We characterized different morphologies by scanning electron microscopy, electron dispersive scattering spectroscopy, dynamic light scattering, horizontal attenuated total reflection-infrared spectroscopy and Raman spectroscopy. The predominant structure is selected by its size in a sort of supramolecular Darwinian competition in this process and is described here.

  4. Synthesis, Crystal Structure and Water Vapor Adsorption Properties of a Porous Supramolecular Architecture

    Directory of Open Access Journals (Sweden)

    Rui Qiao

    2017-10-01

    Full Text Available A new complex, [Cu4(HL4(H2O14] (1, H3L·HCl = 5-((4-carboxypiperidin-1-ylmethylisophthalic acid hydrochloride, has been prepared and characterized by single-crystal X-ray diffraction, elemental analysis, IR spectroscopy and powder X-ray diffraction (PXRD. The result of the X-ray diffraction analysis reveals that the complex crystallizes in monoclinic, space group C2/c and three unique Cu(II atoms that are connected by partially deprotonated HL2− anion to form a cyclic structure. The rich hydrogen bonding and π-π non-covalent packing interactions extend cyclic units into a three-dimensional (3D supramolecular polymer. Moreover, the thermogravimetric (TG analysis and water vapor adsorption property of 1 were also discussed.

  5. Supra-amphiphiles: a new bridge between colloidal science and supramolecular chemistry.

    Science.gov (United States)

    Kang, Yuetong; Liu, Kai; Zhang, Xi

    2014-06-03

    In addition to conventional amphiphiles, an emerging research area is supra-amphiphiles, which are constructed on the basis of noncovalent interactions and dynamic covalent bonds. In this feature article, we have provided a general introduction to the concept, design principles, and topologies of supra-amphiphiles, starting from some rationally tailored building blocks. In addition, we highlight some progress in the functional assembly of supra-amphiphiles, such as responsive nanoscale carriers, antibacterial and antitumor agents, fluorescent-based chemical sensors, and enzyme mimics. The supra-amphiphile is a new bridge between colloidal science and supramolecular chemistry, and it is a field where we can make full use of our imaginative power.

  6. Supramolecular Complex Antioxidant Consisting of Vitamins C, E and Hydrophilic-Hydrophobic Silica Nanoparticles

    Science.gov (United States)

    Laguta, I. V.; Kuzema, P. O.; Stavinskaya, O. N.; Kazakova, O. A.

    Samples with varied amount of surface trimethylsilyl groups were obtained via gas-phase chemical modification of silica nanoparticles. The biocompatibility tests conducted in erythrocyte suspension have shown that hydrophobization of silica decreases its damaging effect to the cells. Being wettable in aqueous media, partially silylated silicas have higher affinity to hydrophobic bioactive molecules in comparison with the initial silica. Novel antioxidant consisting of vitamins C and E and silica with 40% of surface trimethylsilyl groups was formulated. It was found that supramolecular complexes are formed on the silica surface due to the affinity of water- and fat-soluble antioxidants to hydrophilic silanol and hydrophobic trimethylsilyl groups, respectively. Test reactions (total phenolic index determination, DPPH test) and in vitro studies (spectral analysis of erythrocyte suspensions undergoing UV irradiation) revealed the correlation between antioxidant activity of the complex antioxidant and the vitamins’ content. The antioxidant remained active during long-term storage under standard conditions.

  7. The Reciprocal Principle of Selectand-Selector-Systems in Supramolecular Chromatography †.

    Science.gov (United States)

    Schurig, Volker

    2016-11-15

    In selective chromatography and electromigration methods, supramolecular recognition of selectands and selectors is due to the fast and reversible formation of association complexes governed by thermodynamics. Whereas the selectand molecules to be separated are always present in the mobile phase, the selector employed for the separation of the selectands is either part of the stationary phase or is added to the mobile phase. By the reciprocal principle, the roles of selector and selectand can be reversed. In this contribution in honor of Professor Stig Allenmark, the evolution of the reciprocal principle in chromatography is reviewed and its advantages and limitations are outlined. Various reciprocal scenarios, including library approaches, are discussed in efforts to optimize selectivity in separation science.

  8. Synthesis, crystal and supramolecular structure of rac-N-acetyl-2- thiohydantoin-asparagine

    Directory of Open Access Journals (Sweden)

    Gerzon E. Delgado

    2014-05-01

    Full Text Available The title compound, C7H9N3O3S, also known as rac-N-acetyl-5-propionamide-2-thioxo-imidazolidin-4-one, crystallize in the monoclinic system with space group P21/n (Nº14, Z=4, and unit cell parameters a= 9.338 (7 Å, b= 7.545 (5 Å, c= 13.212 (10 Å, E= 97.10 (2°, V= 932.8 (12 Å3. The acetyl group and the mean plane of the ureido group form an angle of 81.0 (2°. In the supramolecular structure, the molecules are joined by N--H···O hydrogen bonds into cyclic structures with graph-set R2 2(14 and R2 2(16, forming a three-dimensional network.

  9. Supramolecular Structure and Mechanical Characteristics of Ultrahigh-Molecular-Weight Polyethylene-Inorganic Nanoparticle Nanocomposites

    International Nuclear Information System (INIS)

    Okhlopkova, T. A.; Borisova, R. V.; Nikiforov, L. A.; Spiridonov, A. M.; Okhlopkova, A. A.; Cho, Jin-Ho; Jeong, Dae-Yong

    2016-01-01

    We investigated the mechanical properties and structure of polymeric nanocomposites (PNCs) with anultrahigh-molecular-weight polyethylene (UHMWPE) matrix and aluminum and silicon oxide and nitride nanoparticle (NP) fillers. Mixing with a paddle mixer or by joint mechanical activation in a planetary mill was used for the PNC preparation. Joint mechanical activation afforded PNCs with better mechanical properties than paddle mixing. Scanning electron microscopy suggested that the poorer mechanical properties can be attributed to the disordered regions and imperfect spherulites in the PNC supramolecular structure arising from paddle mixing. The better mechanical properties observed with joint mechanical activation may derive from the uniform NP distribution in the polymer matrix and absence of disordered regions.

  10. Natural supramolecular building blocks: from virus coat proteins to viral nanoparticles.

    Science.gov (United States)

    Liu, Zhi; Qiao, Jing; Niu, Zhongwei; Wang, Qian

    2012-09-21

    Viruses belong to a fascinating class of natural supramolecular structures, composed of multiple copies of coat proteins (CPs) that assemble into different shapes with a variety of sizes from tens to hundreds of nanometres. Because of their advantages including simple/economic production, well-defined structural features, unique shapes and sizes, genetic programmability and robust chemistries, recently viruses and virus-like nanoparticles (VLPs) have been used widely in biomedical applications and materials synthesis. In this critical review, we highlight recent advances in the use of virus coat proteins (VCPs) and viral nanoparticles (VNPs) as building blocks in self-assembly studies and materials development. We first discuss the self-assembly of VCPs into VLPs, which can efficiently incorporate a variety of different materials as cores inside the viral protein shells. Then, the self-assembly of VNPs at surfaces or interfaces is summarized. Finally, we discuss the co-assembly of VNPs with different functional materials (178 references).

  11. Generation of Supramolecular Chirality around Twofold Rotational or Helical Axes in Crystalline Assemblies of Achiral Components

    Directory of Open Access Journals (Sweden)

    Mikiji Miyata

    2015-10-01

    Full Text Available A multi-point approximation method clarifies supramolecular chirality of twofold rotational or helical assemblies as well as bundles of the one-dimensional (1D assemblies. While one-point approximation of materials claims no chirality generation of such assemblies, multi-point approximations do claim possible generation in the 1D assemblies of bars and plates. Such chirality derives from deformations toward three-axial directions around the helical axes. The chiral columns are bundled in chiral ways through symmetry operations. The preferable right- or left-handed columns are bundled together to yield chiral crystals with right- or left-handedness, respectively, indicating that twofold helix symmetry operations cause chiral crystals composed of achiral components via a three-stepwise and three-directional process.

  12. Evolution of heterogeneity accompanying sol-gel transitions in a supramolecular hydrogel.

    Science.gov (United States)

    Matsumoto, Yuji; Shundo, Atsuomi; Ohno, Masashi; Tsuruzoe, Nobutomo; Goto, Masahiro; Tanaka, Keiji

    2017-10-18

    When a peptide amphiphile is dispersed in water, it self-assembles into a fibrous network, leading to a supramolecular hydrogel. When the gel is physically disrupted by shaking, it transforms into a sol state. After aging at room temperature for a while, it spontaneously returns to the gel state, called sol-gel transition. However, repeating the sol-gel transition often causes a change in the rheological properties of the gel. To gain a better understanding of the sol-gel transition and its reversibility, we herein examined the thermal motion of probe particles at different locations in a supramolecular hydrogel. The sol obtained by shaking the gel was heterogeneous in terms of the rheological properties and the extent decreased with increasing aging time. This time course of heterogeneity, or homogeneity, which corresponded to the sol-to-gel transition, was observed for the 1st cycle. However, this was not the case for the 2nd and 3rd cycles; the heterogeneity was preserved even after aging. Fourier-transform infrared spectroscopy, small-angle X-ray scattering, and atomic force and confocal laser scanning microscopies revealed that, although the molecular aggregation states of amphiphiles both in the gel and sol remained unchanged with the cycles, the fibril density diversified to high and low density regions even after aging. The tracking of particles with different sizes indicated that the partial mesh size in the high density region and the characteristic length scale of the density fluctuation were smaller than 50 nm and 6 μm, respectively.

  13. Crystal structure of a supramolecular lithium complex of p-tert-butylcalix[4]arene

    Directory of Open Access Journals (Sweden)

    Manabu Yamada

    2018-05-01

    Full Text Available Crystals of a supramolecular lithium complex with a calix[4]arene derivative, namely tetramethanollithium 5,11,17,23-tetra-tert-butyl-25,26,27-trihydroxy-28-oxidocalix[4]arene methanol monosolvate, [Li(CH3OH4](C44H55O4·CH3OH or [Li(CH3OH4]+·(calix[4]arene−]·CH3OH (where calix[4]arene− represents a mono-anion species because of deprotonation of one H atom of the calixarene hydroxy groups, were obtained from p-tert-butylcalix[4]arene reacted with LiH in tetrahydrofuran, followed by recrystallization from methanol. The asymmetric unit comprises one mono-anionic calixarene molecule, one Li+ cation coordinated to four methanol molecules, and one methanol molecule included in the calixarene cavity. The calixarene molecule maintains a cone conformation by intramolecular hydrogen bonding between one phenoxide (–O− and three pendent calixarene hydroxy groups (–OH. The coordinated methanol molecules around the metal cation play a significant role in forming the supramolecular assembly. The crystal structure of this assembly is stabilized by three sets of intermolecular interactions: (i hydrogen bonds involving the –OH and –O− moieties of the calixarene molecules, the –OH groups of the coordinated methanol molecules, and the –OH group of the methanol molecule included in the calixarene cavity; (ii C—H...π interactions between the calixarene molecules and/or the coordinated methanol molecules; (iii O—H...π interactions between the calixarene molecule and the included methanol molecule.

  14. Luminescent lanthanide complexes with 4-acetamidobenzoate: Synthesis, supramolecular assembly via hydrogen bonds, crystal structures and photoluminescence

    International Nuclear Information System (INIS)

    Yin Xia; Fan Jun; Wang Zhihong; Zheng Shengrun; Tan Jingbo; Zhang Weiguang

    2011-01-01

    Four new luminescent complexes, namely, [Eu(aba) 2 (NO 3 )(C 2 H 5 OH) 2 ] (1), [Eu(aba) 3 (H 2 O) 2 ].0.5 (4, 4'-bpy).2H 2 O (2), [Eu 2 (aba) 4 (2, 2'-bpy) 2 (NO 3 ) 2 ].4H 2 O (3) and [Tb 2 (aba) 4 (phen) 2 (NO 3 ) 2 ].2C 2 H 5 OH (4) were obtained by treating Ln(NO 3 ) 3 .6H 2 O and 4-acetamidobenzoic acid (Haba) with different coligands (4, 4'-bpy=4, 4'-bipyridine, 2, 2'-bpy=2, 2'-bipyridine, and phen=1, 10-phenanthroline). They exhibit 1D chains (1-2) and dimeric structures (3-4), respectively. This structural variation is mainly attributed to the change of coligands and various coordination modes of aba molecules. Moreover, the coordination units are further connected via hydrogen bonds to form 2D even 3D supramolecular networks. These complexes show characteristic emissions in the visible region at room temperature. In addition, thermal behaviors of four complexes have been investigated under air atmosphere. The relationship between the structures and physical properties has been discussed. - Graphical abstract: Structure variation of four complexes is attributed to the change of coligands and various coordination modes of aba molecules. Moreover, they show characteristic emissions in the visible region. Highlights: → Auxiliary ligands have played the crucial roles on the structures of the resulting complexes. → Isolated structure units are further assembled via H-bonds to form supramolecular networks. → These solid-state complexes exhibit strong, characteristic emissions in the visible region.

  15. Multi-functionalized side-chain supramolecular polymers: A methodology towards tunable functional materials

    Science.gov (United States)

    Nair, Kamlesh Prabhakaran

    Even as we see a significant growth in the field of supramolecular polymers in the last ten years, multi-functionalized systems have been scarcely studied. Noncovalent multi-functionalization provides unique advantages such as rapid materials optimization via reversible functionalization as well as for the tuning of materials properties by exploiting the differences in the nature of these reversible interactions. This thesis involves the design principles, synthesis & methodology of supramolecular side-chain multi-functionalized polymers. The combination of a functionally tolerant & controlled polymerization technique such as ROMP with multiple noncovalent interactions such as hydrogen bonding, metal coordination and ionic interactions has been successfully used to synthesize these polymers. Furthermore, the orthogonality between the above interactions in block/random copolymers has been studied in detail. It has been found that the studied interactions were orthogonal to each other. To validate the viability of this methodology using multiple orthogonal interactions towards materials design noncovalent crosslinking of polymers has been used as a potential application. Three classes of networks have been studied: complementary multiple hydrogen bonded networks, metal crosslinked networks, & multi-functionalized hydrogen bonded and metal coordinated networks. The first room temperature decrosslinking by exclusive complementary hydrogen bonded interactions has been successfully achieved. Furthermore network properties have been successfully tuned by varying the network micro-structure which in turn was tuned by the hydrogen bonding motifs used for inter-chain crosslinking. By combining two different noncovalent interactions used for inter-chain crosslinking, it was possible to make multi-functionalized materials whose properties could be controlled by varying the crosslinking strategy. Hence by employing multi-functionalization methodology, important materials

  16. Spectrofluorimetric study of the β-cyclodextrin-dapsone-linear alcohol supramolecular system and determination of dapsone

    International Nuclear Information System (INIS)

    Ma Li; Tang Bo; Chu Chun

    2002-01-01

    Dapsone (DDS) forms a 1:1 supramolecular complex with β-cyclodextrin (β-CD) both in the absence and presence of linear alcohols. The apparent association constants (K app ) were measured using a steady-state fluorescence method. K app decreases linearly with an increasing number of carbon atoms in the chain of the alcohol. We attribute this to a competition between dapsone and linear alcohol for the β-CD hydrophobic cavity as detailed analysis of K app as a function of the concentration of alcohol suggests that the interactions in the β-CD-dapsone-linear alcohol system do not result in the formation of ternary supramolecular complex. Quenching the fluorescence of dapsone with NaI shows that the β-CD cavity acts as a shield against contact between dapsone and this aqueous phase quencher, while addition of alcohols inhibits this protective effect. This again suggests that alcohols occupy the space within the β-CD cavity with the result that dapsone molecules are forced to reside in the aqueous environment. Based on the significant enhancement of the fluorescence intensity of dapsone produced through complex formation, a spectrofluorimetric method for the determination of dapsone in bulk aqueous solution in the presence of β-CD is developed. The linear relationship between the fluorescence intensity and dapsone concentration was obtained in the range of 3.39 to 1.50x10 3 ng ml -1 , with a correlation coefficient (r) of 0.9998. The detection limit was 1.02 ng ml -1 . There was no interference from the excipients normally used in tablet formulations. The application of the present method to the determination of dapsone in tablets and human plasma gave satisfactory results and was compared with the pharmacopoeia method

  17. Supramolecular biomaterials

    NARCIS (Netherlands)

    Webber, Matthew J.; Appel, Eric A.; Meijer, E. W.; Langer, Robert

    2015-01-01

    Polymers, ceramics and metals have historically dominated the application of materials in medicine. Yet rationally designed materials that exploit specific, directional, tunable and reversible non-covalent interactions offer unprecedented advantages: they enable modular and generalizable platforms

  18. Supramolecular Chemistry

    Indian Academy of Sciences (India)

    A dream target of nature inspired synthesis is to prepare 'smart' functional molecules which are so de- ... erativity, the free energy change (ΔG) is either decreased or in- .... The AIE strategy offers advantages such as high selectivity, sensitivity,.

  19. Molecular and Supramolecular Changes in Polybutylene Succinate (PBS and Polybutylene Succinate Adipate (PBSA Copolymer during Degradation in Various Environmental Conditions

    Directory of Open Access Journals (Sweden)

    Michał Puchalski

    2018-03-01

    Full Text Available In this paper, the influence of the various degradation conditions, on the molecular and supramolecular structure of polybutylene succinate (PBS and polybutylene succinate adipate (PBSA copolymer during degradation is described. The experiment was carried out by the use of injection molded samples and normalized conditions of biodegradation in soil, composting and artificial weathering. Materials were studied by size-exclusion chromatography (SEC coupled with multiangle laser light scattering (MALLS detection and wide-angle X-ray diffraction (WAXD. Additionally, the physical and mechanical properties of the samples were determined. The performed experiments clearly show difference impacts of the selected degradation conditions on the macroscopic, supramolecular and molecular parameters of the studied aliphatic polyesters. The structural changes in PBS and PBSA explain the observed changes in the physical and mechanical properties of the obtained injection molded samples.

  20. A supramolecular structure insight for conversion property of cellulose in hot compressed water: Polymorphs and hydrogen bonds changes.

    Science.gov (United States)

    Wang, Yan; Lian, Jie; Wan, Jinquan; Ma, Yongwen; Zhang, Yingshi

    2015-11-20

    Waste paper samples with different cellulose supramolecular structure were treated in hot compressed water (HCW) at 375°C and 22.5MPa within 200s to evaluate the specific effect mechanism of cellulose supramolecular structure on the conversion of waste paper to reusable resource. Although the distribution of liquid products and the oligosaccharides were related to reaction time, depolymerization and decrystallization of the cellulose, the characteristics absorption peak of cellulose from FTIR analysis and crystal structure of the cellulose detected in the residues with hydrolysis rate up 96.5% indicated crystal structure was the dominant factor that affect conversion behavior of waste paper. The conversion of cellulose Iβ to cellulose Iα or cellulose I(α+β) in HCW demonstrated that the recrystallization occurred during the decrystallization of cellulose through the rearrangement of hydrogen bonds. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Effective removal of coordinated copper from wastewater using a new dithiocarbamate-type supramolecular heavy metal precipitant.

    Science.gov (United States)

    Fu, Fenglian; Zeng, Haiyan; Cai, Qinhong; Qiu, Rongliang; Yu, Jimmy; Xiong, Ya

    2007-11-01

    A new dithiocarbamate-type heavy metal precipitant, sodium 1,3,5-hexahydrotriazinedithiocarbamate (HTDC), was prepared and used to remove coordinated copper from wastewater. In the reported dithiocarbamate-type precipitants, HTDC possesses the highest percentage of the effective functional groups. It could effectively precipitate copper to less than 0.5mgl(-1) from both synthetic and actual industrial wastewater containing CuEDTA in the range of pH 3-9. UV-vis spectral investigation and elemental analysis suggested that the precipitate was a kind of coordination supramolecular compound, [Cu(3)(HTDC)(2)](n). The toxicity characteristic leaching procedure (TCLP) and semi-dynamic leaching test (SDLT) indicated that the supramolecular precipitate was non-hazardous and stable in weak acid and alkaline conditions. Tests of an anion exchange resin D231 provided a clue to simultaneously remove excess HTDC and residual CuEDTA in practical process of wastewater treatment.

  2. Toward a versatile toolbox for cucurbit[n]uril-based supramolecular hydrogel networks through in situ polymerization.

    Science.gov (United States)

    Liu, Ji; Soo Yun Tan, Cindy; Lan, Yang; Scherman, Oren A

    2017-09-15

    The success of exploiting cucurbit[ n ]uril (CB[ n ])-based molecular recognition in self-assembled systems has sparked a tremendous interest in polymer and materials chemistry. In this study, polymerization in the presence of host-guest complexes is applied as a modular synthetic approach toward a diverse set of CB[8]-based supramolecular hydrogels with desirable properties, such as mechanical strength, toughness, energy dissipation, self-healing, and shear-thinning. A range of vinyl monomers, including acrylamide-, acrylate-, and imidazolium-based hydrophilic monomers, could be easily incorporated as the polymer backbones, leading to a library of CB[8] hydrogel networks. This versatile strategy explores new horizons for the construction of supramolecular hydrogel networks and materials with emergent properties in wearable and self-healable electronic devices, sensors, and structural biomaterials. © 2017 The Authors. Journal of Polymer Science Part A: Polymer Chemistry Published by Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 3105-3109.

  3. Supramolecularly assembled water layers stabilized by sebacic anions in complexes of Zn(II) and Co(II)

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Two three-dimensional supramolecular water architectures,[Zn(phen)3]2 ·[Zn(C10H16O4)·(H2O)3]·(C10H16O4)2·20H2O(1) and [Co(phen)3]2 ·[Co(H2O)6]·(C10H16O4)3·30H2O(2)[phen=1,10-Phenanthroline,C10H16O4=sebacic dianion],have been synthesized and characterized by IR,elemental analysis,thermogravimetric analysis,and single-crystal X-ray diffractions.The two structures both contain extensive hydrogen bonding between water molecules as well as between water molecules and sebacic anions.The water molecules and sebacic acid O atoms assembled 2D supramolecular corrugated sheets with different morphology in the two complexes.

  4. A supramolecular look at microenvironmental regulation of limbal epithelial stem cells and the differentiation of their progeny

    Directory of Open Access Journals (Sweden)

    Marcela Aldrovani

    Full Text Available ABSTRACT Various approaches have been taken to improve our knowledge of the microenvironmental regulation of limbal epithelial stem cells. Researchers have extensively investigated the roles of growth factors, survival factors, cytokines, enzymes, and permeable molecules secreted by the limbal cells. However, recent evidence suggests that stem cell fate (i.e., self-renewal or differentiation can also be influenced by biophysical and mechanical cues related to the supramolecular organization and the liquid crystalline (mesophase nature of the stromal extracellular matrix. These cues can be sensed by stem cells and transduced into intracellular biochemical and functional responses, a process known as mechanotransduction. The objective of this review is to offer perspectives on the supramolecular microenvironmental regulation of limbal epithelial stem cells and the differentiation of their progeny.

  5. A change in the composition of supramolecular DNA-bound phospholipids in thymus and liver of gamma-irradiated rats

    International Nuclear Information System (INIS)

    Krasichkova, Z.I.; Strazhevskaya, N.B.

    1984-01-01

    The composition of supramolecular DNA (SM DNA)-bound phospholipids (PL) of thymus and liver of intact rats and those 2 min, 2, 6 and 24 h after γ-irradiation (9.7 Gy) was studied. In norm, supramolecular DNA of the thymus was shown to contain 6.7 μg PL/mg DNA, and that of the liver, 6.1 μg PL/mg DNA, the main components of PL being cardiolipin (CL) and phosphatidylethanolamine (PEA). Substantial changes were detected in the PL composition of SM DNA of γ,irradiated rat organs. During the postirradiation period the concentration of PEA and CL in thymus SM DNA changed symbatically and irreversibly decAeased to traces; whereas in SM DNA of the liver, their concentrations changed antibatically and decreased only to a definite level thus maintaining the necessary ''lipid volume''. It was shown that PL were not restored in SM DNA of the radiopesistant liver

  6. A Ferrocene-Based Catecholamide Ligand: the Consequences of Ligand Swivel for Directed Supramolecular Self-Assembly

    Energy Technology Data Exchange (ETDEWEB)

    Mugridge, Jeffrey; Fiedler, Dorothea; Raymond, Kenneth

    2010-02-04

    A ferrocene-based biscatecholamide ligand was prepared and investigated for the formation of metal-ligand supramolecular assemblies with different metals. Reaction with Ge(IV) resulted in the formation of a variety of Ge{sub n}L{sub m} coordination complexes, including [Ge{sub 2}L{sub 3}]{sup 4-} and [Ge{sub 2}L{sub 2}({mu}-OMe){sub 2}]{sup 2-}. The ligand's ability to swivel about the ferrocenyl linker and adopt different conformations accounts for formation of many different Ge{sub n}L{sub m} species. This study demonstrates why conformational ligand rigidity is essential in the rational design and directed self-assembly of supramolecular complexes.

  7. Post-synthetic transformation of a Zn(ii) polyhedral coordination network into a new supramolecular isomer of HKUST-1.

    Science.gov (United States)

    Chen, Yao; Wojtas, Lukasz; Ma, Shengqian; Zaworotko, Michael J; Zhang, Zhenjie

    2017-08-03

    A Zn-based porphyrin containing metal-organic material (porphMOM-1) was transformed into a novel Cu-based porphyrin-encapsulating metal-organic material (porph@HKUST-1-β) via a one-pot post-synthetic modification (PSM) process involving both metal ion exchange and linker installation of trimesic acid. HKUST-1-β is the first example of yao topology and is to our knowledge the first supramolecular isomer of the archetypal coordination network HKUST-1.

  8. Co-assembly of Peptide Amphiphiles and Lipids into Supramolecular Nanostructures Driven by Anion-π Interactions

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Zhilin; Erbas, Aykut; Tantakitti, Faifan; Palmer, Liam C.; Jackman, Joshua A.; Olvera de la Cruz, Monica; Cho, Nam-Joon; Stupp, Samuel I. (Nanyang); (NWU)

    2017-06-01

    Co-assembly of binary systems driven by specific non-covalent interactions can greatly expand the structural and functional space of supramolecular nanostructures. We report here on the self-assembly of peptide amphiphiles and fatty acids driven primarily by anion-π interactions. The peptide sequences investigated were functionalized with a perfluorinated phenylalanine residue to promote anion-π interactions with carboxylate headgroups in fatty acids. These interactions were verified here by NMR and circular dichroism experiments as well as investigated using atomistic simulations. Positioning the aromatic units close to the N-terminus of the peptide backbone near the hydrophobic core of cylindrical nanofibers leads to strong anion-π interactions between both components. With a low content of dodecanoic acid in this position, the cylindrical morphology is preserved. However, as the aromatic units are moved along the peptide backbone away from the hydrophobic core, the interactions with dodecanoic acid transform the cylindrical supramolecular morphology into ribbon-like structures. Increasing the ratio of dodecanoic acid to PA leads to either the formation of large vesicles in the binary systems where the anion-π interactions are strong, or a heterogeneous mixture of assemblies when the peptide amphiphiles associate weakly with dodecanoic acid. Our findings reveal how co-assembly involving designed specific interactions can drastically change supramolecular morphology and even cross from nano to micro scales.

  9. Normal and reversed supramolecular chirality of insulin fibrils probed by vibrational circular dichroism at the protofilament level of fibril structure.

    Science.gov (United States)

    Kurouski, Dmitry; Dukor, Rina K; Lu, Xuefang; Nafie, Laurence A; Lednev, Igor K

    2012-08-08

    Fibrils are β-sheet-rich aggregates that are generally composed of several protofibrils and may adopt variable morphologies, such as twisted ribbons or flat-like sheets. This polymorphism is observed for many different amyloid associated proteins and polypeptides. In a previous study we proposed the existence of another level of amyloid polymorphism, namely, that associated with fibril supramolecular chirality. Two chiral polymorphs of insulin, which can be controllably grown by means of small pH variations, exhibit opposite signs of vibrational circular dichroism (VCD) spectra. Herein, using atomic force microscopy (AFM) and scanning electron microscopy (SEM), we demonstrate that indeed VCD supramolecular chirality is correlated not only by the apparent fibril handedness but also by the sense of supramolecular chirality from a deeper level of chiral organization at the protofilament level of fibril structure. Our microscopic examination indicates that normal VCD fibrils have a left-handed twist, whereas reversed VCD fibrils are flat-like aggregates with no obvious helical twist as imaged by atomic force microscopy or scanning electron microscopy. A scheme is proposed consistent with observed data that features a dynamic equilibrium controlled by pH at the protofilament level between left- and right-twist fibril structures with distinctly different aggregation pathways for left- and right-twisted protofilaments. Copyright © 2012 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  10. Supramolecular metal-organic frameworks that display high homogeneous and heterogeneous photocatalytic activity for H2 production

    Science.gov (United States)

    Tian, Jia; Xu, Zi-Yue; Zhang, Dan-Wei; Wang, Hui; Xie, Song-Hai; Xu, Da-Wen; Ren, Yuan-Hang; Wang, Hao; Liu, Yi; Li, Zhan-Ting

    2016-05-01

    Self-assembly has a unique presence when it comes to creating complicated, ordered supramolecular architectures from simple components under mild conditions. Here, we describe a self-assembly strategy for the generation of the first homogeneous supramolecular metal-organic framework (SMOF-1) in water at room temperature from a hexaarmed [Ru(bpy)3]2+-based precursor and cucurbit[8]uril (CB[8]). The solution-phase periodicity of this cubic transition metal-cored supramolecular organic framework (MSOF) is confirmed by small-angle X-ray scattering and diffraction experiments, which, as supported by TEM imaging, is commensurate with the periodicity in the solid state. We further demonstrate that SMOF-1 adsorbs anionic Wells-Dawson-type polyoxometalates (WD-POMs) in a one-cage-one-guest manner to give WD-POM@SMOF-1 hybrid assemblies. Upon visible-light (500 nm) irradiation, such hybrids enable fast multi-electron injection from photosensitive [Ru(bpy)3]2+ units to redox-active WD-POM units, leading to efficient hydrogen production in aqueous media and in organic media. The demonstrated strategy opens the door for the development of new classes of liquid-phase and solid-phase ordered porous materials.

  11. Supramolecular oligothiophene microfibers spontaneously assembled on surfaces or coassembled with proteins inside live cells.

    Science.gov (United States)

    Barbarella, Giovanna; Di Maria, Francesca

    2015-08-18

    During the last few decades, multifunctional nano- and microfibers made of semiconducting π-conjugated oligomers and polymers have generated much interest because of a broad range of applications extending from sensing to bioelectronic devices and (opto)electronics. The simplest technique for the fabrication of these anisotropic supramolecular structures is to let the molecules do the work by spontaneous organization driven by the information encoded in their molecular structure. Oligothiophenes-semiconducting and fluorescent compounds that have been extensively investigated for applications in thin-film field-effect transistors and solar cells and to a lesser extent as dyes for fluorescent labeling of proteins, DNA, and live cells-are particularly suited as building blocks for supramolecular architectures because of the peculiar properties of the thiophene ring. Because of the great polarizability of sulfur outer-shell electrons and the consequent facile geometric deformability and adaptability of the ring to the environment, thiophene can generate multiple nonbonding interactions to promote non-covalent connections between blocks. Furthermore, sulfur can be hypervalent, i.e., it can accommodate more than the eight electrons normally associated with s and p shells. Hypervalent oligothiophene-S,S-dioxides whose oxygen atoms can be involved in hydrogen bonding have been synthesized. These compounds are amphiphilic, and some of them are able to spontaneously cross the membrane of live cells. Hypervalent nonbonding interactions of divalent sulfur, defined as weak coordination to a proximate nitrogen or oxygen, have also been invoked in the solid-state packing of many organic molecules and in the architecture of proteins. In this Account, we describe two different types of thiophene-based building blocks that can induce the spontaneous formation of nanostructured microfibers in very different environments. The first, based on the synthesis of "sulfur

  12. Supramolecular architectures in layer-by-layer films of single-walled carbon nanotubes, chitosan and cobalt (II) phthalocyanine

    Energy Technology Data Exchange (ETDEWEB)

    Sousa Luz, Roberto A. de; Martins, Marccus Victor A.; Magalhaes, Janildo L. [Departamento de Quimica, Centro de Ciencias da Natureza, Universidade Federal do Piaui, Teresina - PI, CEP 64049-550 (Brazil); Siqueira, Jose R. [Instituto de Ciencias Exatas, Naturais e Educacao, Universidade Federal do Triangulo Mineiro, Uberaba - MG, CEP 38025-180, Brazil (Brazil); Zucolotto, Valtencir; Oliveira, Osvaldo N. [Instituto de Fisica de Sao Carlos, Universidade de Sao Paulo, Sao Carlos - SP, CEP 13560-970 (Brazil); Crespilho, Frank N. [Centro de Ciencias Naturais e Humanas, Universidade Federal do ABC, Santo Andre - SP, CEP 09210-170 (Brazil); Cantanhede da Silva, Welter, E-mail: welter@ufpi.edu.br [Departamento de Quimica, Centro de Ciencias da Natureza, Universidade Federal do Piaui, Teresina - PI, CEP 64049-550 (Brazil)

    2011-11-01

    Highlights: {yields} Platforms were assembled from cobalt phthalocyanine, chitosan and carbon nanotubes. {yields} Supramolecular organization of multilayer films was investigated. {yields} Increase of the supramolecular charge transfer after carbon nanotube incorporation. {yields} Functional modulation based on constitutional dynamic chemistry was achieved. - Abstract: The building of supramolecular structures in nanostructured films has been exploited for a number of applications, with the film properties being controlled at the molecular level. In this study, we report on the layer-by-layer (LbL) films combining cobalt (II) tetrasulfonated phthalocyanine (CoTsPc), chitosan (Chit) and single-walled carbon nanotubes (SWCNTs) in two architectures, {l_brace}Chit/CoTsPc{r_brace}{sub n} and {l_brace}Chit-SWCNTs/CoTsPc{r_brace}{sub n} (n = 1-10). The physicochemical properties of the films were evaluated and the multilayer formation was monitored with microgravimetry measurements using a quartz microbalance crystal and an electrochemical technique. According to atomic force microscopy (AFM) results, the incorporation of SWCNTs caused the films to be thicker, with a thickness ca. 3 fold that of a 2-bilayer LbL film with no SWCNTs. Cyclic voltammetry revealed a quasi-reversible, one electron process with E{sub 1/2} at -0.65 V (vs SCE) and an irreversible oxidation process at 0.80 V in a physiological medium for both systems, which can be attributed to [CoTsPc(I)]{sup 5-}/[CoTsPc(II)]{sup 4-} and CoTsPc(II) to CoTsPc(III), respectively. The {l_brace}Chit-SWCNTs/CoTsPc{r_brace}{sub 5} multilayer film exhibited an increased faradaic current, probably associated with the supramolecular charge transfer interaction between cobalt phthalocyanine and SWCNTs. The results demonstrate that an intimate contact at the supramolecular level between functional SWCNTs immobilized into biocompatible chitosan polymer and CoTsPc improves the electron flow from CoTsPc redox sites to the

  13. "Intelligent" design of molecular materials: Understanding the concepts of design in supramolecular synthesis of network solids

    Science.gov (United States)

    Moulton, Brian D.

    This work endeavors to delineate modern paradigms for crystal engineering, i.e. the design and supramolecular synthesis of functional molecular materials. Paradigms predicated on an understanding of the geometry of polygons and polyhedra are developed. The primary focus is on structural determination by single crystal X-ray crystallography, structural interpretation using a suite of graphical visualization and molecular modeling software, and on the importance of proper graphical representation in the presentation and explanation of crystal structures. A detailed analysis of a selected series of crystal structures is presented. The reduction of these molecular networks to schematic representations that illustrate their fundamental connectivity facilitates the understanding of otherwise complex supramolecular solids. Circuit symbols and Schlafli notation are used to describe the network topologies, which enables networks of different composition and metrics to be easily compared. This reveals that molecular orientations in the crystals and networks are commensurate with networks that can be derived from spherical close packed lattices. The development of a logical design strategy for a new class of materials based on our understanding of the chemical composition and topology of these networks is described. The synthesis and crystal structure of a series of new materials generated by exploitation of this design strategy is presented, in addition to a detailed analysis of the topology of these materials and their relationship to a 'parent' structure. In summary, this dissertation demonstrates that molecular polygons can self-assemble at their vertexes to produce molecular architectures and crystal structures that are consistent with long established geometric dogma. The design strategy represents a potentially broad ranging approach to the design of nanoporous structures from a wide range of chemical components that are based on molecular shape rather than chemical

  14. Photoactive assemblies of organic compounds and biomolecules: drug-protein supramolecular systems.

    Science.gov (United States)

    Vayá, Ignacio; Lhiaubet-Vallet, Virginie; Jiménez, M Consuelo; Miranda, Miguel A

    2014-06-21

    The properties of singlet and triplet excited states are strongly medium-dependent. Hence, these species constitute valuable tools as reporters to probe compartmentalised microenvironments, including drug@protein supramolecular systems. In the present review, the attention is focused on the photophysical properties of the probe drugs (rather than those of the protein chromophores) using transport proteins (serum albumins and α1-acid glycoproteins) as hosts. Specifically, fluorescence measurements allow investigation of the structural and dynamic properties of biomolecules or their complexes. Thus, the emission quantum yields and the decay kinetics of the drug singlet excited states provide key information to determine important parameters such as the stoichiometry of the complex, the binding constant, the relative degrees of occupancy of the different compartments, etc. Application of the FRET concept allows determination of donor-acceptor interchromophoric distances. In addition, anisotropy measurements can be related to the orientation of the drug within the binding sites, where the degrees of freedom for conformational relaxation are restricted. Transient absorption spectroscopy is also a potentially powerful tool to investigate the binding of drugs to proteins, where formation of encapsulated triplet excited states is favoured over other possible processes leading to ionic species (i.e. radical ions), and their photophysical properties are markedly sensitive to the microenvironment experienced within the protein binding sites. Even under aerobic conditions, the triplet lifetimes of protein-complexed drugs are remarkably long, which provides a broad dynamic range for identification of distinct triplet populations or for chiral discrimination. Specific applications of the laser flash photolysis technique include the determination of drug distribution among the bulk solution and the protein binding sites, competition of two types of proteins to bind a drug

  15. Self-assembly of supramolecular triarylamine nanowires in mesoporous silica and biocompatible electrodes thereof

    Science.gov (United States)

    Licsandru, Erol-Dan; Schneider, Susanne; Tingry, Sophie; Ellis, Thomas; Moulin, Emilie; Maaloum, Mounir; Lehn, Jean-Marie; Barboiu, Mihail; Giuseppone, Nicolas

    2016-03-01

    Biocompatible silica-based mesoporous materials, which present high surface areas combined with uniform distribution of nanopores, can be organized in functional nanopatterns for a number of applications. However, silica is by essence an electrically insulating material which precludes applications for electro-chemical devices. The formation of hybrid electroactive silica nanostructures is thus expected to be of great interest for the design of biocompatible conducting materials such as bioelectrodes. Here we show that we can grow supramolecular stacks of triarylamine molecules in the confined space of oriented mesopores of a silica nanolayer covering a gold electrode. This addressable bottom-up construction is triggered from solution simply by light irradiation. The resulting self-assembled nanowires act as highly conducting electronic pathways crossing the silica layer. They allow very efficient charge transfer from the redox species in solution to the gold surface. We demonstrate the potential of these hybrid constitutional materials by implementing them as biocathodes and by measuring laccase activity that reduces dioxygen to produce water.Biocompatible silica-based mesoporous materials, which present high surface areas combined with uniform distribution of nanopores, can be organized in functional nanopatterns for a number of applications. However, silica is by essence an electrically insulating material which precludes applications for electro-chemical devices. The formation of hybrid electroactive silica nanostructures is thus expected to be of great interest for the design of biocompatible conducting materials such as bioelectrodes. Here we show that we can grow supramolecular stacks of triarylamine molecules in the confined space of oriented mesopores of a silica nanolayer covering a gold electrode. This addressable bottom-up construction is triggered from solution simply by light irradiation. The resulting self-assembled nanowires act as highly conducting

  16. Chapter 8: Selective Stoichiometric and Catalytic Reactivity in the Confines of a Chiral Supramolecular Assembly

    Energy Technology Data Exchange (ETDEWEB)

    University of California, Berkeley; Lawrence Berkeley National Laboratory; Raymond, Kenneth; Pluth, Michael D.; Bergman, Robert G.; Raymond, Kenneth N.

    2007-09-27

    Nature uses enzymes to activate otherwise unreactive compounds in remarkable ways. For example, DNases are capable of hydrolyzing phosphate diester bonds in DNA within seconds,[1-3]--a reaction with an estimated half-life of 200 million years without an enzyme.[4] The fundamental features of enzyme catalysis have been much discussed over the last sixty years in an effort to explain the dramatic rate increases and high selectivities of enzymes. As early as 1946, Linus Pauling suggested that enzymes must preferentially recognize and stabilize the transition state over the ground state of a substrate.[5] Despite the intense study of enzymatic selectivity and ability to catalyze chemical reactions, the entire nature of enzyme-based catalysis is still poorly understood. For example, Houk and co-workers recently reported a survey of binding affinities in a wide variety of enzyme-ligand, enzyme-transition-state, and synthetic host-guest complexes and found that the average binding affinities were insufficient to generate many of the rate accelerations observed in biological systems.[6] Therefore, transition-state stabilization cannot be the sole contributor to the high reactivity and selectivity of enzymes, but rather, other forces must contribute to the activation of substrate molecules. Inspired by the efficiency and selectivity of Nature, synthetic chemists have admired the ability of enzymes to activate otherwise unreactive molecules in the confines of an active site. Although much less complex than the evolved active sites of enzymes, synthetic host molecules have been developed that can carry out complex reactions with their cavities. While progress has been made toward highly efficient and selective reactivity inside of synthetic hosts, the lofty goal of duplicating enzymes specificity remains.[7-9] Pioneered by Lehn, Cram, Pedersen, and Breslow, supramolecular chemistry has evolved well beyond the crown ethers and cryptands originally studied.[10-12] Despite the

  17. Final Technical Report: Targeting DOE-Relevant Ions with Supramolecular Strategies, DE-SC0010555

    Energy Technology Data Exchange (ETDEWEB)

    Bowman-James, Kristin [Univ. of Kansas, Lawrence, KS (United States). Dept. of Chemistry

    2017-04-13

    The effectiveness of three popular supramolecular strategies to selectively target negatively charged ions (anions) was evaluated. Ions of interest included oxo anions, particularly sulfate, that hamper nuclear waste remediation. Three objectives were pursued using a simple building block strategies and by strategically placing anion-binding sites at appropriate positions on organic host molecules. The goal of the first objective was to assess the influence of secondary, tertiary and quaternized amines on binding tetrahedral anions using mixed amide/amine macrocyclic and urea/amine hosts containing aromatic or heteroaromatic spacers. Objective 2 focused on the design of ion pair hosts, using mixed macrocyclic anion hosts joined through polyether linkages. Objective 3 was to explore the synthesis of new metal-linked extended macrocyclic frameworks to leverage anion binding. Key findings were that smaller 24-membered macrocycles provided the most complementary binding for sulfate ion and mixed urea/amine chelates showed enhanced binding over amide corollaries in addition to being highly selective for SO42- in the presence of small quantities of water. In addition to obtaining prototype metal-linked macrocyclic anion hosts, a new dipincer ligand was designed that can be used to link macrocyclic or other supramolecular hosts in extended frameworks. When the tetraamide-based pincers are bound to two metal ions, an interesting phenomenon occurs. Upon deprotonation of the amides, two new protons appear between adjacent carbonyl pairs on the ligand, which may modify the chemistry, and metal-metal interactions in the complexes. Gel formation occurred for some of these extended hosts, and the physical properties are currently under investigation. The new tetracarboxamide-based pincers can also provide basic frameworks for double macrocycles capable of binding ion pairs as well as for binding metal ions and exploring intermetallic interactions through

  18. Structure-directing star-shaped block copolymers: supramolecular vesicles for the delivery of anticancer drugs.

    Science.gov (United States)

    Yang, Chuan; Liu, Shao Qiong; Venkataraman, Shrinivas; Gao, Shu Jun; Ke, Xiyu; Chia, Xin Tian; Hedrick, James L; Yang, Yi Yan

    2015-06-28

    Amphiphilic polycarbonate/PEG copolymer with a star-like architecture was designed to facilitate a unique supramolecular transformation of micelles to vesicles in aqueous solution for the efficient delivery of anticancer drugs. The star-shaped amphipilic block copolymer was synthesized by initiating the ring-opening polymerization of trimethylene carbonate (TMC) from methyl cholate through a combination of metal-free organo-catalytic living ring-opening polymerization and post-polymerization chain-end derivatization strategies. Subsequently, the self-assembly of the star-like polymer in aqueous solution into nanosized vesicles for anti-cancer drug delivery was studied. DOX was physically encapsulated into vesicles by dialysis and drug loading level was significant (22.5% in weight) for DOX. Importantly, DOX-loaded nanoparticles self-assembled from the star-like copolymer exhibited greater kinetic stability and higher DOX loading capacity than micelles prepared from cholesterol-initiated diblock analogue. The advantageous disparity is believed to be due to the transformation of micelles (diblock copolymer) to vesicles (star-like block copolymer) that possess greater core space for drug loading as well as the ability of such supramolecular structures to encapsulate DOX. DOX-loaded vesicles effectively inhibited the proliferation of 4T1, MDA-MB-231 and BT-474 cells, with IC50 values of 10, 1.5 and 1.0mg/L, respectively. DOX-loaded vesicles injected into 4T1 tumor-bearing mice exhibited enhanced accumulation in tumor tissue due to the enhanced permeation and retention (EPR) effect. Importantly, DOX-loaded vesicles demonstrated greater tumor growth inhibition than free DOX without causing significant body weight loss or cardiotoxicity. The unique ability of the star-like copolymer emanating from the methyl cholate core provided the requisite modification in the block copolymer interfacial curvature to generate vesicles of high loading capacity for DOX with significant

  19. Hydrogen bonded 1D-3D supramolecular structures from Benzylamine and organic acidic components

    Science.gov (United States)

    Gao, Xingjun; Li, XiaoLiang; Jin, Shouwen; Hu, Kaikai; Guo, Jianzhong; Guo, Ming; Xu, Weiqiang; Wang, Daqi

    2018-03-01

    Cocrystallization of the commonly available organic amine, benzylamine, with a series of organic acids afforded a total of seven organic salts with the compositions: (benzylamine)2: (p-nitrophenol)2: (H2O) (1) [(HL)2+⋯(npl-)2⋯(H2O), npl- = p-nitrophenolate], (benzylamine): (4-tert-butylbenzoic acid) (2) [(HL+)⋯(tba-), tba- = 4-tert-butylbenzoate], (benzylamine): (3,4-dichlorobenzoic acid) (3) [(HL+)⋯dcba-), dcba- = 3,4-dichlorobenzoate], (benzylamine): (2,5-dihydroxybenzoic acid) (4) [(HL+)⋯(dhba-), dhba- = 2,5-dihydroxybenzoate], (benzylamine): (2-bromo-but-2-enedioic acid) (5) [(HL+)⋯(Hbba-), Hbba- = 2-bromo-hydrogenbut-2-enedioate], (benzylamine): (2,6-pyridinedicarboxylic acid) (6) [(HL+)⋯(Hpdc-), Hpdc- = 2,6-pyridine hydrogendicarboxylate], and (benzylamine)2: (3-nitrophthalic acid): 2(H2O) (7) [(HL+)2⋯(npa2-)⋯(H2O)2, npa2- = 3-nitrophthalate]. The seven salts have been characterised by X-ray diffraction analysis, IR, and elemental analysis, and the melting points of all the salts were also reported. And their structural and supramolecular aspects are fully analyzed. The results reveal that among the seven investigated crystals the NH2 in the benzylamine are protonated when the organic acids are deprotonated, and the crystal packing is interpreted in terms of the strong charge-assisted Nsbnd H⋯O hydrogen bond between the NH3+ and deprotonated acidic groups. Except the Nsbnd H⋯O hydrogen bond, the Osbnd H⋯O hydrogen bonds (charge assisted or neutral) were also found at the salts 1, 4, 5, 6, and 7. Further analysis of the crystal packing of the salts indicated that a different family of additional CHsbnd O/CH2sbnd O, CH-π/CH2-π, Cπ-Cπ, Osbnd O, O-Cπ, O-π, and Cl-π associations also contribute to the stabilization and expansion of the total high-dimensional framework structures. For the coexistence of the various weak nonbonding interactions, these structures adopted a variety of

  20. Supramolecular Influence on Keto-Enol Tautomerism and Thermochromic Properties of o-Hydroxy Schiff Bases

    Directory of Open Access Journals (Sweden)

    Marija Zbačnik

    2016-06-01

    Full Text Available This work presents a study on thermo-optical properties of three Schiff bases (imines in the solid state. The Schiff bases were obtained by means of mechanochemical synthesis using monosubstituted o-hydroxy aromatic aldehydes and monosubstituted aromatic amines. The keto-enol tautomerism and proton transfer via intramolecular O∙∙∙N hydrogen bond of the reported compounds was found to be influenced more by supramolecular interactions than by a temperature change. All products were characterised by powder X-ray diffraction (PXRD, FT-IR spectroscopy, thermogravimetric (TG analysis and differential scanning calorimetry (DSC. Molecular and crystal structures of compounds 1, 2 and 3 were determined by single crystal X-ray diffraction (SCXRD. The molecules of 1 appear to be present as the enol-imine, the molecules of 2 as the keto-amine tautomer and the molecules of 3 exhibit keto-enol tautomeric equilibrium in the solid state. An analysis of Cambridge structural database (CSD data on similar imines has been used for structural comparison. This work is licensed under a Creative Commons Attribution 4.0 International License.

  1. Water-Insoluble Photosensitizer Nanocolloids Stabilized by Supramolecular Interfacial Assembly towards Photodynamic Therapy

    Science.gov (United States)

    Liu, Yamei; Ma, Kai; Jiao, Tifeng; Xing, Ruirui; Shen, Guizhi; Yan, Xuehai

    2017-02-01

    Nanoengineering of hydrophobic photosensitizers (PSs) is a promising approach for improved tumor delivery and enhanced photodynamic therapy (PDT) efficiency. A variety of delivery carriers have been developed for tumor delivery of PSs through the enhanced permeation and retention (EPR) effect. However, a high-performance PS delivery system with minimum use of carrier materials with excellent biocompatibility is highly appreciated. In this work, we utilized the spatiotemporal interfacial adhesion and assembly of supramolecular coordination to achieve the nanoengineering of water-insoluble photosensitizer Chlorin e6 (Ce6). The hydrophobic Ce6 nanoparticles are well stabilized in a aqueous medium by the interfacially-assembled film due to the coordination polymerization of tannic acid (TA) and ferric iron (Fe(III)). The resulting Ce6@TA-Fe(III) complex nanoparticles (referenced as Ce6@TA-Fe(III) NPs) significantly improves the drug loading content (~65%) and have an average size of 60 nm. The Ce6@TA-Fe(III) NPs are almost non-emissive as the aggregated states, but they can light up after intracellular internalization, which thus realizes low dark toxicity and excellent phototoxicity under laser irradiation. The Ce6@TA-Fe(III) NPs prolong blood circulation, promote tumor-selective accumulation of PSs, and enhanced antitumor efficacy in comparison to the free-carrier Ce6 in vivo evaluation.

  2. Template Syntheses, Crystal Structures and Supramolecular Assembly of Hexaaza Macrocyclic Copper(II) Complexes

    International Nuclear Information System (INIS)

    Kim, Taehyung; Kim, Ju Chang; Lough, Alan J.

    2013-01-01

    Two new hexaaza macrocyclic copper(II) complexes were prepared by a template method and structurally characterized. In the solid state, they were self-assembled by intermolecular interactions to form the corresponding supramolecules 1 and 2, respectively. In the structure of 1, the copper(II) macrocycles are bridged by a tp ligand to form a macrocyclic copper(II) dimer. The dimer extends its structure by intermolecular forces such as hydrogen bonds and C-H···π interactions, resulting in the formation of a double stranded 1D supramolecule. In 2, the basic structure is a monomeric copper(II) macrocycle with deprotonated imidazole pendants. An undulated 1D hydrogen bonded array is achieved through hydrogen bonds between imidazole pendants and secondary amines, where the imidazole pendants act as a hydrogen bond acceptor. The 1D hydrogen bonded supramolecular chain is supported by C-H···π interactions between the methyl groups of acetonitrile ligands and imidazole pendants of the copper(II) macrocycles. In both complexes, the introduction of imidazoles to the macrocycle as a pendant plays an important role for the formation of supramolecules, where they act as intermolecular hydrogen bond donors and/or acceptors, C-H···π and π-π interactions

  3. Assembly of one-dimensional supramolecular objects: From monomers to networks

    Science.gov (United States)

    Sayar, Mehmet; Stupp, Samuel I.

    2005-07-01

    One-dimensional supramolecular aggregates can form networks at exceedingly low concentrations. Recent experiments in several laboratories, including our own, have demonstrated the formation of gels by these systems at concentrations well under 1% by weight. The systems of interest in our laboratory form either cylindrical nanofibers or ribbons as a result of strong noncovalent interactions among monomers. The stiffness and interaction energies among these thread-like objects can vary significantly depending on the chemical structure of the monomers used. We have used Monte Carlo simulations to study the structure of the threads and their ability to form networks through bundle formation. The persistence length of the threads was found to be strongly affected not only by stiffness, but also by the strength of attractive two-body interactions among thread segments. The relative values of stiffness and attractive two-body interaction strength determine if threads collapse or create bundles. Only in the presence of sufficiently long threads and bundle formation can these systems assemble into networks of high connectivity.

  4. Synthesis of anatase TiO2 nanoparticles with beta-cyclodextrin as a supramolecular shell.

    Science.gov (United States)

    Li, Landong; Sun, Xiaohong; Yang, Yali; Guan, Naijia; Zhang, Fuxiang

    2006-11-20

    We report a novel, green hydrothermal-synthesis route to well-dispersed anatase TiO2 nanoparticles with particle sizes of 9-16 nm in the presence of beta-CD (beta-cyclodextrin). During the synthesis process, the CD-containing synthesis mixture assembled in both longitudinal and latitudinal directions. Driven by the interaction between molecules, the beta-CDs assembled in the longitudinal direction to form long-chain compounds, whereas in the latitudinal direction, they tended to form regular aggregates through coordination with the Ti species from the hydrolysis of tetrabutyl titanate. In view of the effect of the coordination and the steric hindrance of beta-CDs as a supramolecular shell, homogeneous nuclei and slow growth of TiO2 crystals during the synthesis process was observed, which was responsible for the formation of uniform TiO2 nanoparticles. The low beta-CD dosage and the high product yield (>90%) demonstrated well the potential of this synthesis route in the large-scale industrial production of anatase nanoparticles.

  5. Bio-Inspired Supramolecular Chemistry Provides Highly Concentrated Dispersions of Carbon Nanotubes in Polythiophene

    Directory of Open Access Journals (Sweden)

    Yen-Ting Lin

    2016-06-01

    Full Text Available In this paper we report the first observation, through X-ray diffraction, of noncovalent uracil–uracil (U–U dimeric π-stacking interactions in carbon nanotube (CNT–based supramolecular assemblies. The directionally oriented morphology determined using atomic force microscopy revealed highly organized behavior through π-stacking of U moieties in a U-functionalized CNT derivative (CNT–U. We developed a dispersion system to investigate the bio-inspired interactions between an adenine (A-terminated poly(3-adeninehexyl thiophene (PAT and CNT–U. These hybrid CNT–U/PAT materials interacted through π-stacking and multiple hydrogen bonding between the U moieties of CNT–U and the A moieties of PAT. Most importantly, the U···A multiple hydrogen bonding interactions between CNT–U and PAT enhanced the dispersion of CNT–U in a high-polarity solvent (DMSO. The morphology of these hybrids, determined using transmission electron microscopy, featured grape-like PAT bundles wrapped around the CNT–U surface; this tight connection was responsible for the enhanced dispersion of CNT–U in DMSO.

  6. Supramolecular intermediates in the synthesis of polymeric carbon nitride from melamine cyanurate

    International Nuclear Information System (INIS)

    Dante, Roberto C.; Sánchez-Arévalo, Francisco M.; Chamorro-Posada, Pedro; Vázquez-Cabo, José; Huerta, Lazaro; Lartundo-Rojas, Luis; Santoyo-Salazar, Jaime

    2015-01-01

    The adduct of melamine and cyanuric acid (MCA) was used in past research to produce polymeric carbon nitride and precursors. The reaction yield was considerably incremented by the addition of sulfuric acid. The polymeric carbon nitride formation occurs around 450 °C at temperatures above the sublimation of the adduct components, which occurs around 400 °C. In this report the effect of sulfuric acid on MCA was investigated. It was found that the MCA rosette supramolecular channel structures behave as a solid solvent able to host small molecules, such as sulfuric acid, inside these channels and interact with them. Therefore, the sulfuric acid effect was found to be close to that of a solute that causes a temperature increment of the “solvent sublimation” enough to allowing the formation of polymeric carbon nitride to occur. Sulfate ions are presumably hosted in the rosette channels of MCA as shown by simulations. - Graphical abstract: The blend of melamine cyanurate and sulfuric acid behaves like a solution so that melamine cyanurate decomposition is shifted to temperatures high enough to react and form polymeric carbon nitride. - Highlights: • The adduct of melamine and cyanuric acid behaves as a solid solvent. • The blend of sulfuric acid and melamine cyanurate behaves like a solution. • Melamine cyanurate decomposition is shifted to higher temperatures by sulfuric acid. • The formation of polymeric carbon nitride occurs for these higher temperatures

  7. A two-dimensional Zn coordination polymer with a three-dimensional supra-molecular architecture.

    Science.gov (United States)

    Liu, Fuhong; Ding, Yan; Li, Qiuyu; Zhang, Liping

    2017-10-01

    The title compound, poly[bis-{μ 2 -4,4'-bis-[(1,2,4-triazol-1-yl)meth-yl]biphenyl-κ 2 N 4 : N 4' }bis-(nitrato-κ O )zinc(II)], [Zn(NO 3 ) 2 (C 18 H 16 N 6 ) 2 ] n , is a two-dimensional zinc coordination polymer constructed from 4,4'-bis-[(1 H -1,2,4-triazol-1-yl)meth-yl]-1,1'-biphenyl units. It was synthesized and characterized by elemental analysis and single-crystal X-ray diffraction. The Zn II cation is located on an inversion centre and is coordinated by two O atoms from two symmetry-related nitrate groups and four N atoms from four symmetry-related 4,4'-bis-[(1 H -1,2,4-triazol-1-yl)meth-yl]-1,1'-biphenyl ligands, forming a distorted octa-hedral {ZnN 4 O 2 } coordination geometry. The linear 4,4'-bis-[(1 H -1,2,4-triazol-1-yl)meth-yl]-1,1'-biphenyl ligand links two Zn II cations, generating two-dimensional layers parallel to the crystallographic (132) plane. The parallel layers are connected by C-H⋯O, C-H⋯N, C-H⋯π and π-π stacking inter-actions, resulting in a three-dimensional supra-molecular architecture.

  8. A two-dimensional Zn coordination polymer with a three-dimensional supramolecular architecture

    Directory of Open Access Journals (Sweden)

    Fuhong Liu

    2017-10-01

    Full Text Available The title compound, poly[bis{μ2-4,4′-bis[(1,2,4-triazol-1-ylmethyl]biphenyl-κ2N4:N4′}bis(nitrato-κOzinc(II], [Zn(NO32(C18H16N62]n, is a two-dimensional zinc coordination polymer constructed from 4,4′-bis[(1H-1,2,4-triazol-1-ylmethyl]-1,1′-biphenyl units. It was synthesized and characterized by elemental analysis and single-crystal X-ray diffraction. The ZnII cation is located on an inversion centre and is coordinated by two O atoms from two symmetry-related nitrate groups and four N atoms from four symmetry-related 4,4′-bis[(1H-1,2,4-triazol-1-ylmethyl]-1,1′-biphenyl ligands, forming a distorted octahedral {ZnN4O2} coordination geometry. The linear 4,4′-bis[(1H-1,2,4-triazol-1-ylmethyl]-1,1′-biphenyl ligand links two ZnII cations, generating two-dimensional layers parallel to the crystallographic (132 plane. The parallel layers are connected by C—H...O, C—H...N, C—H...π and π–π stacking interactions, resulting in a three-dimensional supramolecular architecture.

  9. Force and time-dependent self-assembly, disruption and recovery of supramolecular peptide amphiphile nanofibers.

    Science.gov (United States)

    Dikecoglu, F Begum; Topal, Ahmet E; Ozkan, Alper D; Tekin, E Deniz; Tekinay, Ayse B; Guler, Mustafa O; Dana, Aykutlu

    2018-07-13

    Biological feedback mechanisms exert precise control over the initiation and termination of molecular self-assembly in response to environmental stimuli, while minimizing the formation and propagation of defects through self-repair processes. Peptide amphiphile (PA) molecules can self-assemble at physiological conditions to form supramolecular nanostructures that structurally and functionally resemble the nanofibrous proteins of the extracellular matrix, and their ability to reconfigure themselves in response to external stimuli is crucial for the design of intelligent biomaterials systems. Here, we investigated real-time self-assembly, deformation, and recovery of PA nanofibers in aqueous solution by using a force-stabilizing double-pass scanning atomic force microscopy imaging method to disrupt the self-assembled peptide nanofibers in a force-dependent manner. We demonstrate that nanofiber damage occurs at tip-sample interaction forces exceeding 1 nN, and the damaged fibers subsequently recover when the tip pressure is reduced. Nanofiber ends occasionally fail to reconnect following breakage and continue to grow as two individual nanofibers. Energy minimization calculations of nanofibers with increasing cross-sectional ellipticity (corresponding to varying levels of tip-induced fiber deformation) support our observations, with high-ellipticity nanofibers exhibiting lower stability compared to their non-deformed counterparts. Consequently, tip-mediated mechanical forces can provide an effective means of altering nanofiber integrity and visualizing the self-recovery of PA assemblies.

  10. Two 8-Hydroxyquinolinate Based Supramolecular Coordination Compounds: Synthesis, Structures and Spectral Properties

    Directory of Open Access Journals (Sweden)

    Chengfeng Zhu

    2017-03-01

    Full Text Available Two new Cr(III complexes based on 2-substituted 8-hydroxyquinoline ligands, namely [Cr(L13] (1, (HL1=(E-2-[2-(4-nitro-phenyl-vinyl]-8-hydroxy-quinoline and [Cr(L23] (2, (HL2=(E-2-[2-(4-chloro-phenylvinyl]-8-hydroxy-quinoline, were prepared by a facile hydrothermal method and characterized thoroughly by single crystal X-ray diffraction, powder X-ray diffraction, FTIR, TGA, ESI-MS, UV-Visible absorption spectra and fluorescence emission spectra. Single crystal X-ray diffraction analyses showed that the two compounds featured 3D supramolecular architectures constructed from noncovalent interactions, such as π···π stacking, C-H···π, C-H···O, C-Cl···π, C-H···Cl interactions. The thermogravimetric analysis and ESI-MS study of compounds 1 and 2 suggested that the Cr(III complexes possessed good stability both in solid and solution. In addition, the ultraviolet and fluorescence response of the HL1 and HL2 shown marked changes upon their complexation with Cr(III ion, which indicated that the two 8-hydroxyquinolinate based ligand are promising heavy metal chelating agent for Cr3+.

  11. Supramolecular Properties of Triazole-containing Two Armed Peptidomimetics: From Organogelators to Nucleotide-binding Tweezers

    Science.gov (United States)

    Chui, Tin Ki

    This thesis described the development of a new type of branched peptidomimetics using a class of previously reported triazole-containing peptidomimetics as the structural motif. The propensity of these new branched peptiomimetics in being an organogelator, forming supramolecular assemblies and recognizing anions and biomolecules was investigated. The quest began with the preparation of two different series of branched peptidomimetics, namely 69-K-aa3 (aa = V or L) and 70-B-aa3. The former series made use of the flexible L-lysine (K) as the branching unit while the latter series was composed of the relatively rigid 3,5-diminobenzoate (B). In each series, the peptidomimetic arms were composed of solely valine (V) or leucine (L). The effects of the identity of the amino acids and the branching units on the gelation and self-assembling properties of these branched bis(tripeptidomimetic)s were investigated. The 69-K-aa3 series was found to exhibit poor solubility in common organic solvents yet it was able to form strong and stable gels in aromatic solvents. The 70-B-aa3 series, on the other hand, was a poor organogelator despite its excellent solubility. Morphological studies using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed the ability of the former to form a hyperbranched 3D network whereas the latter was only capable of forming isolated spherical lumps. Nevertheless, the latter displayed the ability in forming supramolecular polymers as shown from viscometric studies. Solution-to-gel transition temperature measurement of the gels formed by the 69-K-aa3 series and association constants determination by 1H NMR titration experiments for the supramolecular polymerization of the 70-B-aa3 series both suggested that peptidomimetic arms comprised of valine performed better than those made up of leucine in terms of association strength, and such a difference was attributed to the bulkier nature of the leucine side chain. In order to

  12. Fabrication of CO2 Facilitated Transport Channels in Block Copolymer through Supramolecular Assembly

    Directory of Open Access Journals (Sweden)

    Yao Wang

    2014-05-01

    Full Text Available In this paper, the molecule 12-amidine dodecanoic acid (M with ending groups of carboxyl and amidine groups respectively was designed and synthesized as CO2-responsive guest molecules. The block copolymer polystyrene-b-polyethylene oxide (PS-b-PEO was chosen as the host polymer to fabricate a composite membrane through H-bonding assembly with guest molecule M. We attempted to tune the phase separation structure of the annealed film by varying the amount of M added, and investigated the nanostructures via transmission electron microscope (TEM, fourier transform infrared (FT-IR etc. As a result, a reverse worm-like morphology in TEM image of bright PS phase in dark PEO/M matrix was observed for PS-b-PEO/M1 membrane in which the molar ratio of EO unit to M was 1:1. The following gas permeation measurement indicated that the gas flux of the annealed membranes dramatically increased due to the forming of ordered phase separation structure. As we expected, the obtained composite membrane PS-b-PEO/M1 with EO:M mole ratio of 1:1 presented an evident selectivity for moist CO2 permeance, which is identical with our initial proposal that the guest molecule M in the membranes will play the key role for CO2 facilitated transportation since the amidine groups of M could react reversibly with CO2 molecules in membranes. This work provides a supramolecular approach to fabricating CO2 facilitated transport membranes.

  13. Supramolecular assembly of group 11 phosphorescent metal complexes for chemosensors of alcohol derivatives

    Science.gov (United States)

    Lintang, H. O.; Ghazalli, N. F.; Yuliati, L.

    2018-04-01

    We report on systematic study on vapochromic sensing of ethanol by using phosphorescent trinuclear metal pyrazolate complexes with supramolecular assembly of weak intermolecular metal-metal interactions using 4-(3,5-dimethoxybenzyl)-3,5-dimethyl pyrazole ligand (1) and group 11 metal ions (Cu(I), Ag(I), Au(I)). Upon excitation at 284, the resulting complexes showed emission bands with a peak centered at 616, 473 and 612 nm for 2(Cu), 2(Ag) and 2(Au), respectively. Chemosensor 2(Cu) showed positive response to ethanol vapors in 5 mins by blue-shifting its emission band from 616 to 555 nm and emitting bright orange to green. Otherwise 2(Au) gave shifting from its emission band centered at 612 to 587 nm with Δλ of 25 nm (41%) and color changes from red-orange to light green-orange while 2(Ag) showed quenching in its original emission intensity at 473 nm in 40% with color changes from dark green to less emissive. These results demonstrate that sensing capability of chemosensor 2(Cu) with suitable molecular design of ligand and metal ion in the complex is due to the formation of a weak intermolecular hydrogen bonding interaction of O atom at the methoxy of the benzyl ring with the OH of the vapors at the outside of the molecules.

  14. Dinuclear ru-aqua complexes for selective epoxidation catalysis based on supramolecular substrate orientation effects

    KAUST Repository

    Di Giovanni, Carlo; Poater, Albert; Benet-Buchholz, Jordi; Cavallo, Luigi; Solà , Miquel; Llobet, Antoni A.

    2014-01-01

    Ru-aqua complex {[RuII(trpy)(H2O)] 2(μ-pyr-dc)}+ is a powerful epoxidation catalyst for a wide range of linear and cyclic alkenes. High turnover numbers (TNs), up to 17000, and turnover frequencies (TOF), up to 24120 h-1 (6.7 s -1), have been obtained using PhIO as oxidant. This species presents an outstanding stereospecificity for both cis and trans olefins towards the formation of their corresponding cis and trans epoxides. In addition, it shows different reactivity to cis and trans olefins due to a substrate orientation supramolecular effect transmitted by its ligand scaffold. This effect together with the impressive reaction rates are rationalized using electrochemical techniques and DFT calculations. A new Ru-aqua complex that behaves as a powerful epoxidation catalyst for a wide range of linear and cyclic alkenes is reported. High turnover numbers and frequencies are obtained by using PhIO as oxidant. The complex shows an outstanding stereospecificity for both cis and trans olefins towards the formation of their corresponding cis and trans epoxides (see figure). © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Sensitization effects of supramolecular assemblies on the luminescence of terbium-ion prulifloxacin complexes

    Energy Technology Data Exchange (ETDEWEB)

    Wang Hong; Yi Chongyue; Li Xue; Fang Fang [School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Yang Yajiang, E-mail: yjyang@mail.hust.edu.c [School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2011-04-15

    Luminescence enhancement of terbium-ion prulifloxacin complexes (Tb(III)-PUFX) in supramolecular hydrogels formed by assembly of 1,3:2,4-di-O-benzylidene-D-sorbitol (DBS) was investigated by steady-state fluorescence, varying temperature fluorescence and time-resolved fluorescence. The luminescence images show that Tb(III)-PUFX were dispersed in the DBS gels. The luminescence intensity of Tb(III)-PUFX in the DBS gels was significantly increased in comparison with that in corresponding aqueous solutions. The varying temperature fluorescent spectra show that the luminescence intensity of Tb(III)-PUFX decreased with an increase in the temperature. This implies that the luminescence enhancement of Tb(III)-PUFX is related to the dissociation and the formation of the DBS assemblies. Time-resolved fluorescence measurements show slower rotational motion in DBS gels in comparison with that in the corresponding aqueous solutions. This may be ascribed to a unique microstructure of three-dimensional network formed by DBC aggregates, resulting in deactivation of the nonradiative relaxation. The images of field emission scanning electron microscopy and polarized optical microscopy indicate that the morphology of the DBS assemblies was not influenced upon addition of Tb(III)-PUFX to the DBS gels.

  16. Changes in lignocellulosic supramolecular and ultrastructure during dilute acid pretreatment of Populus and switchgrass

    International Nuclear Information System (INIS)

    Foston, Marcus; Ragauskas, Art J.

    2010-01-01

    Dilute acid pretreatment (DAP) is commonly employed prior to enzymatic deconstruction of cellulose to increase overall sugar and subsequent ethanol yields from downstream bioconversion processes. Typically optimization of pretreatment is evaluated by determining hemicellulose removal, subsequent reactivity towards enzymatic deconstruction, and recoverable polysaccharide yields. In this study, the affect of DAP on the supramolecular and ultrastructure of lignocellulosic biomass was evaluated. A series of dilute acidic pretreatments, employing ∼0.10-0.20 mol/m 3 H 2 SO 4 at ∼160-180 o C, for varying residence times were conducted on both Populus and switchgrass samples. The untreated and pretreated biomass samples were characterized by carbohydrate and lignin analysis, gel permeation chromatography (GPC) and 13 C cross polarization magic angle spinning (CPMAS) NMR spectroscopy. GPC analysis shows a reduction in the molecular weight of cellulose and change in its polydispersity index (PDI) with increasing residence time, indicating that pretreatment is actually degrading the cellulose chains. 13 C CPMAS and non-linear line-fitting of the C 4 region in the carbon spectrum of the isolated cellulose not only showed that the crystallinity index increases with residence time, but that the lateral fibril dimension (LFD) and lateral fibril aggregate dimension (LFAD) increase as well.

  17. Effect of temperature and strain rate on the compressive behaviour of supramolecular polyurethane

    Directory of Open Access Journals (Sweden)

    Tang Xuegang

    2015-01-01

    Full Text Available Supramolecular polyurethanes (SPUs possess thermoresponsive and thermoreversible properties, and those characteristics are highly desirable in both bulk commodity and value-added applications such as adhesives, shape-memory materials, healable coatings and lightweight, impact-resistant structures (e.g. protection for mobile electronics. A better understanding of the mechanical properties, especially the rate and temperature sensitivity, of these materials are required to assess their suitability for different applications. In this paper, a newly developed SPU with tuneable thermal properties was studied, and the response of this SPU to compressive loading over strain rates from 10−3 to 104 s−1 was presented. Furthermore, the effect of temperature on the mechanical response was also demonstrated. The sample was tested using an Instron mechanical testing machine for quasi-static loading, a home-made hydraulic system for moderate rates and a traditional split Hopkinson pressure bars (SHPBs for high strain rates. Results showed that the compression stress-strain behaviour was affected significantly by the thermoresponsive nature of SPU, but that, as expected for polymeric materials, the general trends of the temperature and the rate dependence mirror each other. However, this behaviour is more complicated than observed for many other polymeric materials, as a result of the richer range of transitions that influence the behaviour over the range of temperatures and strain rates tested.

  18. Radical polymerization by a supramolecular catalyst: cyclodextrin with a RAFT reagent

    Directory of Open Access Journals (Sweden)

    Kohei Koyanagi

    2016-11-01

    Full Text Available Supramolecular catalysts have received a great deal of attention because they improve the selectivity and efficiency of reactions. Catalysts with host molecules exhibit specific reaction properties and recognize substrates via host–guest interactions. Here, we examined radical polymerization reactions with a chain transfer agent (CTA that has α-cyclodextrin (α-CD as a host molecule (α-CD-CTA. Prior to the polymerization of N,N-dimethylacrylamide (DMA, we investigated the complex formation of α-CD with DMA. Single X-ray analysis demonstrated that α-CD includes DMA inside its cavity. When DMA was polymerized in the presence of α-CD-CTA using 2,2'-azobis[2-(2-imidazolin-2-ylpropane dihydrochloride (VA-044 as an initiator in an aqueous solution, poly(DMA was obtained in good yield and with narrow molecular weight distribution. In contrast, the polymerization of DMA without α-CD-CTA produced more widely distributed polymers. In the presence of 1,6-hexanediol (C6 diol which works as a competitive molecule by being included in the α-CD cavity, the reaction yield was lower than that without C6 diol.

  19. Structural Consequences of Anionic Host-Cationic Guest Interactions in a Supramolecular Assembly

    Energy Technology Data Exchange (ETDEWEB)

    Pluth, Michael D.; Johnson, Darren W.; Szigethy, Geza; Davis, Anna V.; Teat, Simon J.; Oliver, Allen G.; Bergman, Robert G.; Raymond, Kenneth N.

    2008-07-09

    The molecular structure of the self-assembled supramolecular assembly [M{sub 4}L{sub 6}]{sup 12-} has been explored with different metals (M = Ga{sup III}, Fe{sup III}, Ti{sup IV}) and different encapsulated guests (NEt{sub 4}{sup +}, BnNMe{sub 3}{sup +}, Cp{sub 2}Co{sup +}, Cp*{sub 2}Co{sup +}) by X-ray crystallography. While the identity of the metal ions at the vertices of the M{sub 4}L{sub 6} structure is found to have little effect on the assembly structure, encapsulated guests significantly distort the size and shape of the interior cavity of the assembly. Cations on the exterior of the assembly are found to interact with the assembly through either {pi}-{pi}, cation-{pi}, or CH-{pi} interactions. In some cases, the exterior guests interact with only one assembly, but cations with the ability to form multiple {pi}-{pi} interactions are able to interact with adjacent assemblies in the crystal lattice. The solvent accessible cavity of the assembly is modeled using the rolling probe method and found to range from 253-434 {angstrom}{sup 3}, depending on the encapsulated guest. Based on the volume of the guest and the volume of the cavity, the packing coefficient for each host-guest complex is found to range from 0.47-0.67.

  20. Supramolecular assembly of a series of chiral dendrimers in interfacial films

    International Nuclear Information System (INIS)

    Yuan Jing; Deng Guojun; Fan Qinghua; Liu Minghua

    2004-01-01

    Supramolecular assembly and interfacial properties of a series of novel binaphthyl containing dendrimers from generation 1 through generation 4 have been investigated at the air/water interface and in solid substrates. Due to the lack of either long alkyl chains or strong hydrophilic groups, the dendrimer molecules tend to aggregate together to form stable two-dimensional ultrathin films, as verified by π-A and A-t measurements. Atomic force microscope (AFM) measurements of the transferred one-layer ultrathin films indicate that all the dendrimers show disk-like morphologies, which could be varied in particle size upon changing the surface pressure. The height profiles reveal that the height of the disks is between that of a monolayer and a bilayer, indicating that they are formed due to the aggregation of dendrimers with a distortion and/or partial overlapping. Circular dichroism (CD) spectra of the transferred multilayer films show Cotton effects due to the exciton couplet of the aromatic moieties adjacent to the bis(diphenylphosphino)-binaphthyl moiety, which is an active catalytic site for the dendrimer. With the increment of the generation, the intensity of the Cotton effects increased, suggesting that the optical active site of the dendrimer can be controlled by the outside wedge

  1. Tailored protein encapsulation into a DNA host using geometrically organized supramolecular interactions

    Science.gov (United States)

    Sprengel, Andreas; Lill, Pascal; Stegemann, Pierre; Bravo-Rodriguez, Kenny; Schöneweiß, Elisa-C.; Merdanovic, Melisa; Gudnason, Daniel; Aznauryan, Mikayel; Gamrad, Lisa; Barcikowski, Stephan; Sanchez-Garcia, Elsa; Birkedal, Victoria; Gatsogiannis, Christos; Ehrmann, Michael; Saccà, Barbara

    2017-02-01

    The self-organizational properties of DNA have been used to realize synthetic hosts for protein encapsulation. However, current strategies of DNA-protein conjugation still limit true emulation of natural host-guest systems, whose formation relies on non-covalent bonds between geometrically matching interfaces. Here we report one of the largest DNA-protein complexes of semisynthetic origin held in place exclusively by spatially defined supramolecular interactions. Our approach is based on the decoration of the inner surface of a DNA origami hollow structure with multiple ligands converging to their corresponding binding sites on the protein surface with programmable symmetry and range-of-action. Our results demonstrate specific host-guest recognition in a 1:1 stoichiometry and selectivity for the guest whose size guarantees sufficient molecular diffusion preserving short intermolecular distances. DNA nanocontainers can be thus rationally designed to trap single guest molecules in their native form, mimicking natural strategies of molecular recognition and anticipating a new method of protein caging.

  2. Controlled supramolecular structure of guanosine monophosphate in the interlayer space of layered double hydroxide

    Directory of Open Access Journals (Sweden)

    Gyeong-Hyeon Gwak

    2016-12-01

    Full Text Available Guanosine monophosphates (GMPs were intercalated into the interlayer space of layered double hydroxides (LDHs and the molecular arrangement of GMP was controlled in LDHs. The intercalation conditions such as GMP/LDH molar ratio and reaction temperature were systematically adjusted. When the GMP/LDH molar ratio was 1:2, which corresponds to the charge balance between positive LDH sheets and GMP anions, GMP molecules were well-intercalated to LDH. At high temperature (100 and 80 °C, a single GMP molecule existed separately in the LDH interlayer. On the other hand, at lower temperature (20, 40 and 60 °C, GMPs tended to form ribbon-type supramolecular assemblies. Differential scanning calorimetry showed that the ribbon-type GMP assembly had an intermolecular interaction energy of ≈101 kJ/mol, which corresponds to a double hydrogen bond between guanosine molecules. Once stabilized, the interlayer GMP orientations, single molecular and ribbon phase, were successfully converted to the other phase by adjusting the external environment by stoichiometry or temperature control.

  3. Supramolecular Nanoparticles via Single-Chain Folding Driven by Ferrous Ions.

    Science.gov (United States)

    Wang, Fei; Pu, Hongting; Jin, Ming; Wan, Decheng

    2016-02-01

    Single-chain nanoparticles can be obtained via single-chain folding assisted by intramolecular crosslinking reversibly or irreversibly. Single-chain folding is also an efficient route to simulate biomacromolecules. In present study, poly(N-hydroxyethylacrylamide-co-4'-(propoxy urethane ethyl acrylate)-2,2':6',2''-terpyridine) (P(HEAm-co-EMA-Tpy)) is synthesized via reversible addition fragmentation chain transfer polymerization. Single-chain folding and intramolecular crosslinking of P(HEAm-co-EMA-Tpy) are achieved via metal coordination chemistry. The intramolecular interaction is characterized on ultraviolet/visible spectrophotometer (UV-vis spectroscopy), proton nuclear magnetic resonance ((1)H NMR), and differential scanning calorimetry (DSC). The supramolecular crosslinking mediated by Fe(2+) plays an important role in the intramolecular collapsing of the single-chain and the formation of the nanoparticles. The size and morphology of the nanoparticles can be controlled reversibly via metal coordination chemistry, which can be characterized by dynamic light scattering (DLS), transmission electron microscope (TEM), and atomic force microscope (AFM). © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Unexpected Rotamerism at the Origin of a Chessboard Supramolecular Assembly of Ruthenium Phthalocyanine.

    Science.gov (United States)

    Mattioli, Giuseppe; Larciprete, Rosanna; Alippi, Paola; Bonapasta, Aldo Amore; Filippone, Francesco; Lacovig, Paolo; Lizzit, Silvano; Paoletti, Anna Maria; Pennesi, Giovanna; Ronci, Fabio; Zanotti, Gloria; Colonna, Stefano

    2017-11-16

    We have investigated the formation and the properties of ultrathin films of ruthenium phthalocyanine (RuPc) 2 vacuum deposited on graphite by scanning tunneling microscopy and synchrotron photoemission spectroscopy measurements, interpreted in close conjunction with ab initio simulations. Thanks to its unique dimeric structure connected by a direct Ru-Ru bond, (RuPc) 2 can be found in two stable rotameric forms separated by a low-energy barrier. Such isomerism leads to a peculiar organization of the molecules in flat, horizontal layers on the graphite surface, characterized by a chessboard-like alternation of the two rotamers. Moreover, the molecules are vertically connected to form π-stacked columnar pillars of akin rotamers, compatible with the high conductivity measured in (RuPc) 2 powders. Such features yield an unprecedented supramolecular assembly of phthalocyanine films, which could open interesting perspectives toward the realization of new architectures of organic electronic devices. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. An AAA-DDD triply hydrogen-bonded complex easily accessible for supramolecular polymers.

    Science.gov (United States)

    Han, Yi-Fei; Chen, Wen-Qiang; Wang, Hong-Bo; Yuan, Ying-Xue; Wu, Na-Na; Song, Xiang-Zhi; Yang, Lan

    2014-12-15

    For a complementary hydrogen-bonded complex, when every hydrogen-bond acceptor is on one side and every hydrogen-bond donor is on the other, all secondary interactions are attractive and the complex is highly stable. AAA-DDD (A=acceptor, D=donor) is considered to be the most stable among triply hydrogen-bonded sequences. The easily synthesized and further derivatized AAA-DDD system is very desirable for hydrogen-bonded functional materials. In this case, AAA and DDD, starting from 4-methoxybenzaldehyde, were synthesized with the Hantzsch pyridine synthesis and Friedländer annulation reaction. The association constant determined by fluorescence titration in chloroform at room temperature is 2.09×10(7)  M(-1) . The AAA and DDD components are not coplanar, but form a V shape in the solid state. Supramolecular polymers based on AAA-DDD triply hydrogen bonded have also been developed. This work may make AAA-DDD triply hydrogen-bonded sequences easily accessible for stimuli-responsive materials. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Building inorganic supramolecular architectures using principles adopted from the organic solid state

    Directory of Open Access Journals (Sweden)

    Marijana Đaković

    2018-01-01

    Full Text Available In order to develop transferable and practical avenues for the assembly of coordination complexes into architectures with specific dimensionality, a strategy utilizing ligands capable of simultaneous metal coordination and self-complementary hydrogen bonding is presented. The three ligands used, 2(1H-pyrazinone, 4(3H-pyrimidinone and 4(3H-quinazolinone, consistently deliver the required synthetic vectors in a series of CdII coordination polymers, allowing for reproducible supramolecular synthesis that is insensitive to the different steric and geometric demands from potentially disruptive counterions. In all nine crystallographically characterized compounds presented here, directional intermolecular N—H...O hydrogen bonds between ligands on adjacent complex building blocks drive the assembly and orientation of discrete building blocks into largely predictable topologies. Furthermore, whether the solids are prepared from solution or through liquid-assisted grinding, the structural outcome is the same, thus emphasizing the robustness of the synthetic protocol. The details of the molecular recognition events that take place in this series of compounds have been clearly delineated and rationalized in the context of calculated molecular electrostatic potential surfaces.

  7. Dinuclear ru-aqua complexes for selective epoxidation catalysis based on supramolecular substrate orientation effects

    KAUST Repository

    Di Giovanni, Carlo

    2014-03-03

    Ru-aqua complex {[RuII(trpy)(H2O)] 2(μ-pyr-dc)}+ is a powerful epoxidation catalyst for a wide range of linear and cyclic alkenes. High turnover numbers (TNs), up to 17000, and turnover frequencies (TOF), up to 24120 h-1 (6.7 s -1), have been obtained using PhIO as oxidant. This species presents an outstanding stereospecificity for both cis and trans olefins towards the formation of their corresponding cis and trans epoxides. In addition, it shows different reactivity to cis and trans olefins due to a substrate orientation supramolecular effect transmitted by its ligand scaffold. This effect together with the impressive reaction rates are rationalized using electrochemical techniques and DFT calculations. A new Ru-aqua complex that behaves as a powerful epoxidation catalyst for a wide range of linear and cyclic alkenes is reported. High turnover numbers and frequencies are obtained by using PhIO as oxidant. The complex shows an outstanding stereospecificity for both cis and trans olefins towards the formation of their corresponding cis and trans epoxides (see figure). © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Supramolecular intermediates in the synthesis of polymeric carbon nitride from melamine cyanurate

    Energy Technology Data Exchange (ETDEWEB)

    Dante, Roberto C., E-mail: rcdante@yahoo.com [Facultad de Mecánica, Escuela Politécnica Nacional (EPN), Ladrón de Guevara E11-253, Quito (Ecuador); Sánchez-Arévalo, Francisco M. [Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de Mexico, Apdo. Postal 70-360, Cd. Universitaria, Mexico D.F. 04510 (Mexico); Chamorro-Posada, Pedro [Dpto. de Teoría de la Señal y Comunicaciones e IT, Universidad de Valladolid, ETSI Telecomunicación, Paseo Belén 15, 47011 Valladolid (Spain); Vázquez-Cabo, José [Dpto. de Teoría de la Señal y Comunicaciones, Universidad de Vigo, ETSI Telecomunicación, Lagoas Marcosende s/n, Vigo (Spain); Huerta, Lazaro [Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de Mexico, Apdo. Postal 70-360, Cd. Universitaria, Mexico D.F. 04510 (Mexico); Lartundo-Rojas, Luis [Centro de Nanociencias y Micro y Nanotecnologías—IPN, Luis Enrique Erro s/n, U. Prof. Adolfo López Mateos, 07738 Ciudad de Mexico, Distrito Federal (Mexico); Santoyo-Salazar, Jaime [Departamento de Física, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, CINVESTAV-IPN, Apdo. Postal 14-740, Mexico D.F. 07360 (Mexico); and others

    2015-03-15

    The adduct of melamine and cyanuric acid (MCA) was used in past research to produce polymeric carbon nitride and precursors. The reaction yield was considerably incremented by the addition of sulfuric acid. The polymeric carbon nitride formation occurs around 450 °C at temperatures above the sublimation of the adduct components, which occurs around 400 °C. In this report the effect of sulfuric acid on MCA was investigated. It was found that the MCA rosette supramolecular channel structures behave as a solid solvent able to host small molecules, such as sulfuric acid, inside these channels and interact with them. Therefore, the sulfuric acid effect was found to be close to that of a solute that causes a temperature increment of the “solvent sublimation” enough to allowing the formation of polymeric carbon nitride to occur. Sulfate ions are presumably hosted in the rosette channels of MCA as shown by simulations. - Graphical abstract: The blend of melamine cyanurate and sulfuric acid behaves like a solution so that melamine cyanurate decomposition is shifted to temperatures high enough to react and form polymeric carbon nitride. - Highlights: • The adduct of melamine and cyanuric acid behaves as a solid solvent. • The blend of sulfuric acid and melamine cyanurate behaves like a solution. • Melamine cyanurate decomposition is shifted to higher temperatures by sulfuric acid. • The formation of polymeric carbon nitride occurs for these higher temperatures.

  9. Supramolecular architecture based on [Fe(CN)6]3- metallotectons and melaminium synthons

    Science.gov (United States)

    Krichen, Firas; Walha, Siwar; Lhoste, Jérôme; Bulou, Alain; Kabadou, Ahlem; Goutenoire, François

    2017-10-01

    Assembly involving [Fe(CN)6]3- metallotectons as building units and melaminium organic cation has been envisioned in order to elaborate a hybrid supramolecular based on ionic H-bonds with formula {(H-mel)4[Fe(CN)6]Cl} (H-mel+: melaminium cation). The compound has been prepared by diffusion method and characterized by single-crystal X-ray diffraction, EDX analysis, and Raman-IR spectroscopies with assignment from ab initio calculations. The melaminium exhibit self cationic coupling with cyclic hydrogen bonds to give a one dimensional {[H-mel]+}∝ synthon. Therefore, these cationic ribbons are inter-linked via hydrogen bonds by the anionic tectons [Fe(CN)6]3- and chlorine anion resulting on a 3D network. Molecular hirshfeld surfaces revealed that the crystal structure has been supported mainly by Nsbnd H⋯N and Nsbnd H⋯Cl intermolecular Hydrogen bonds and by favoured C⋯C and C⋯N weak interactions.

  10. Supramolecular architecture of metal-organic frameworks involving dinuclear copper paddle-wheel complexes.

    Science.gov (United States)

    Gomathi, Sundaramoorthy; Muthiah, Packianathan Thomas

    2013-12-15

    The two centrosymmetric dinuclear copper paddle-wheel complexes tetrakis(μ-4-hydroxybenzoato-κ(2)O:O')bis[aquacopper(II)] dimethylformamide disolvate dihydrate, [Cu2(C7H5O3)4(H2O)2]·2C3H7NO·2H2O, (I), and tetrakis(μ-4-methoxybenzoato-κ(2)O:O')bis[(dimethylformamide-κO)copper(II)], [Cu2(C8H7O3)4(C3H7NO)2], (II), crystallize with half of the dinuclear paddle-wheel cage unit in the asymmetric unit and, in addition, complex (I) has one dimethylformamide (DMF) and one water solvent molecule in the asymmetric unit. In both (I) and (II), two Cu(II) ions are bridged by four syn,syn-η(1):η(1):μ carboxylate groups, showing a paddle-wheel cage-type structure with a square-pyramidal coordination geometry. The equatorial positions of (I) and (II) are occupied by the carboxylate groups of 4-hydroxy- and 4-methoxybenzoate ligands, and the axial positions are occupied by aqua and DMF ligands, respectively. The three-dimensional supramolecular metal-organic framework of (I) consists of three different R2(2)(20) and an R4(4)(36) ring motif formed via O-H···O and OW-HW···O hydrogen bonds. Complex (II) simply packs as molecular species.

  11. Charge Effect on the Formation of Polyoxometalate-Based Supramolecular Polygons Driven by Metal Coordination.

    Science.gov (United States)

    Piot, Madeleine; Hupin, Sébastien; Lavanant, Hélène; Afonso, Carlos; Bouteiller, Laurent; Proust, Anna; Izzet, Guillaume

    2017-07-17

    The metal-driven self-assembly of a Keggin-based hybrid bearing two remote pyridine units was investigated. The resulting supramolecular species were identified by combination of 2D diffusion NMR spectroscopy (DOSY) and electrospray ionization mass spectrometry (ESI-MS) as a mixture of molecular triangles and squares. This behavior is different from that of the structural analogue Dawson-based hybrid displaying a higher charge, which only led to the formation of molecular triangles. This study highlights the decisive effect of the charge of the POMs in their self-assembly processes that disfavors the formation of large assemblies. An isothermal titration calorimetry (ITC) experiment confirmed the stronger binding in the case of the Keggin hybrids. A correlation between the diffusion coefficient D and the molecular mass M of the POM-based building block and its coordination oligomers was also observed. We show that the diffusion coefficient of these compounds is mainly determined by their occupied volume rather than by their shape.

  12. Double level selection in a constitutional dynamic library of coordination driven supramolecular polygons.

    Science.gov (United States)

    Rancan, Marzio; Tessarolo, Jacopo; Casarin, Maurizio; Zanonato, Pier Luigi; Quici, Silvio; Armelao, Lidia

    2014-07-21

    A constitutional dynamic library (CDL) of Cu(II) metallo-supramolecular polygons has been studied as a bench test to examine an interesting selection case based on molecular recognition. Sorting of the CDL polygons is achieved through a proper guest that is hosted into the triangular metallo-macrocycle constituent. Two selection mechanisms are observed, a guest induced path and a guest templated self-assembly (virtual library approach). Remarkably, the triangular host can accommodate several guests with a degree of selectivity ranging from ∼1 to ∼10(4) for all possible guest pairs. A double level selection operates: guests drive the CDL toward the triangular polygon, and, at the same time, this is able to pick a specific guest from a set of competitive molecules, according to a selectivity-affinity correlation. Association constants of the host-guest systems have been determined. Guest competition and exchange studies have been analyzed through variable temperature UV-Vis absorption spectroscopy and single crystal X-ray diffraction studies. Molecular structures and electronic properties of the triangular polygon and of the host-guest systems also have been studied by means of all electrons density functional theory (DFT) and time-dependent density functional theory (TDDFT) calculations including dispersive contributions. DFT outcomes ultimately indicate the dispersive nature of the host-guest interactions, while TDDFT results allow a thorough assignment of the host and host-guests spectral features.

  13. A new zinc(II supramolecular square: Synthesis, crystal structure, thermal behavior and luminescence

    Directory of Open Access Journals (Sweden)

    Wang Xiu-Yan

    2015-01-01

    Full Text Available A new square-shaped Zn(II complex, namely, [Zn4(L4(phen4]•6H2O (1 (L = 2-hydroxynicotinate and phen = 1,10- phenanthroline, has been synthesized under hydrothermal condition. The crystal of 1 belongs to triclinic, space group P -1 with a = 10.773(2 Å, b = 12.641(3 Å, c = 13.573(3 Å, α = 107.44(3º, β = 102.66(3º, γ = 93.89(3°, C72H56N12O18Zn4, Mr = 1638.77, V = 1702.8(6 Å3 , Z = 1, Dc = 1.598 g/cm3 , S = 1.045, μ(MoKα = 1.475 mm-1 , F(000 = 836, R = 0.0472 and wR = 0.0919. In 1, four L ligands bridge four Zn(II atoms to form a square-shaped structure, where four phen ligands are respectively located on four corners of the square. The π-π stacking interactions extend the adjacent squares into a 1D supramolecular chain. The thermal behavior of 1 has been characterized. Moreover, its solid state luminescence property has been studied at room temperature.

  14. Adaptive resolution simulation of polarizable supramolecular coarse-grained water models

    International Nuclear Information System (INIS)

    Zavadlav, Julija; Praprotnik, Matej; Melo, Manuel N.; Marrink, Siewert J.

    2015-01-01

    Multiscale simulations methods, such as adaptive resolution scheme, are becoming increasingly popular due to their significant computational advantages with respect to conventional atomistic simulations. For these kind of simulations, it is essential to develop accurate multiscale water models that can be used to solvate biophysical systems of interest. Recently, a 4-to-1 mapping was used to couple the bundled-simple point charge water with the MARTINI model. Here, we extend the supramolecular mapping to coarse-grained models with explicit charges. In particular, the two tested models are the polarizable water and big multiple water models associated with the MARTINI force field. As corresponding coarse-grained representations consist of several interaction sites, we couple orientational degrees of freedom of the atomistic and coarse-grained representations via a harmonic energy penalty term. This additional energy term aligns the dipole moments of both representations. We test this coupling by studying the system under applied static external electric field. We show that our approach leads to the correct reproduction of the relevant structural and dynamical properties

  15. Two supramolecular complexes based on polyoxometalates and Co-EDTA units via covalent connection or non-covalent interaction

    Energy Technology Data Exchange (ETDEWEB)

    Teng, Chunlin; Xiao, Hanxi [Key Laboratory of Theoretical Organic Chemistry and Functional Molecule for Ministry of Education, Hunan University of Science and Technology, Xiangtan 411201 (China); Cai, Qing [Chemistry Department, City University of New York, New York, NY 10016 (United States); Tang, Jianting; Cai, Tiejun [Key Laboratory of Theoretical Organic Chemistry and Functional Molecule for Ministry of Education, Hunan University of Science and Technology, Xiangtan 411201 (China); Deng, Qian, E-mail: dengqian10502@163.com [Key Laboratory of Theoretical Organic Chemistry and Functional Molecule for Ministry of Education, Hunan University of Science and Technology, Xiangtan 411201 (China)

    2016-11-15

    Two new 3D network organic-inorganic hybrid supramolecular complexes ([Na{sub 6}(CoEDTA){sub 2}(H{sub 2}O){sub 13}]·(H{sub 2}SiW{sub 12}O{sub 40})·xH{sub 2}O)n (1) and [CoH{sub 4}EDTA(H{sub 2}O)]{sub 2}(SiW{sub 12}O{sub 40})·15H{sub 2}O (2) (H{sub 4}EDTA=Ethylenediamine tetraacetic acid) have been successfully synthesized by solution method, and characterized by infrared spectrum (IR), thermogravimetric-differential thermal analysis (TG-DTA), cyclic voltammetry (CV) and single{sup −}crystal X-ray diffraction (XRD). Both of the complexes are the supramolecules, but with different liking mode, they are two representative models of supramolecule. complex (1) is a 3D infinite network supramolecular coordination polymer with a rare multi-metal sturcture of sodium-cobalt-containing, which is mainly linked through coordinate-covalent bonds. While complex (2) is normal supramolecule, which linked by non-covalent interactions, such as H-bonding interaction, electrostatic interaction and van der waals force. Both of complex (1) and (2) exhibit good catalytic activities for catalytic oxidation of methanol, when the initial concentration of methanol is 3.0 g m{sup −3}, flow rate is 10 mL min{sup −1}, and the quality of catalyst is 0.2 g, for complex (1) and complex (2) the maximum elimination rates of methanol are 85% (150 °C) and 92% (120 °C), respectively. - Graphical abstract: Two new organic-inorganic hybrid supramolecular complexes based on Co-EDTA, and Keggin polyanions have been successfully synthesized with different pH value by solution method. They are attributed to two representative models of supramolecule. Complex(1) is an infinite coordination polymer with a rare multi-metal sturcture of sodium-cobalt-containing, which is mainly linked through covalent bonds. Complex (2) is a normal supramolecule, which linked by non-covalent interactions of H-bonding interaction, electrostatic interaction and van der waals force. - Highlights: • Two supramolecules

  16. Improved enzyme-mediated synthesis and supramolecular self-assembly of naturally occurring conjugates of beta-sitosterol

    Czech Academy of Sciences Publication Activity Database

    Wimmerová, Martina; Siglerová, Věra; Šaman, David; Šlouf, Miroslav; Kaletová, Eva; Wimmer, Zdeněk

    2017-01-01

    Roč. 117, JAN (2017), s. 38-43 ISSN 0039-128X R&D Projects: GA MŠk LD15012; GA MŠk(CZ) LO1507 Institutional support: RVO:61389030 ; RVO:61388963 ; RVO:61389013 Keywords : glycosides * esterification * resolution * sterols * esters * foods * l. * beta-Sitosterol * Acylated steryl glycoside * Lipase * Ionic liquid * Supramolecular self-assembly * Pharmacological activity Subject RIV: CC - Organic Chemistry; CD - Macromolecular Chemistry (UMCH-V) OBOR OECD: Organic chemistry; Polymer science (UMCH-V); Organic chemistry (UOCHB-X) Impact factor: 2.282, year: 2016

  17. Design of supramolecular ordered systems for mesoscopic colloids and molecular composites. Progress report, November 10, 1993--June 10, 1994

    Energy Technology Data Exchange (ETDEWEB)

    1995-01-01

    During this reporting period, the authors group has been active in five areas of research: (1) improvements on their x-ray instrumentation at the SUNY Beamline, National Synchrotron Light Source (NSLS) so that they can perform new experiments which are not accessible otherwise; (2) characterization of functionalized hairy rod polymers designed for studying the macromolecular structures in molecular composites; (3) investigation of supramolecular ordered systems composed mainly of block copolymers from dilute to concentrated solutions, including the gel state; (4) evolution of crystalline structures in polymer blends and melts; and (5) multiphase structure of segment polyurethanes.

  18. Helical self-organization and hierarchical self-assembly of an oligoheterocyclic pyridine-pyridazine strand into extended supramolecular fibers.

    Science.gov (United States)

    Cuccia, Louis A; Ruiz, Eliseo; Lehn, Jean-Marie; Homo, Jean-Claude; Schmutz, Marc

    2002-08-02

    The synthesis and characterization of an alternating pyridine-pyridazine strand comprising thirteen heterocycles are described. Spontaneous folding into a helical secondary structure is based on a general molecular self-organization process enforced by the conformational information encoded within the primary structure of the molecular strand itself. Conformational control based on heterocyclic "helicity codons" illustrates a strategy for designing folding properties into synthetic oligomers (foldamers). Strong intermolecular interactions of the highly ordered lock-washer subunits of compound 3 results in hierarchical supramolecular self-assembly into protofibrils and fibrils. Compound 3 also forms mechanically stable two-dimensional Langmuir-Blodgett and cast thin films.

  19. Direct and quantitative characterization of dynamic ligand exchange between coordination-driven self-assembled supramolecular polygons.

    Science.gov (United States)

    Zheng, Yao-Rong; Stang, Peter J

    2009-03-18

    The direct observation of dynamic ligand exchange between Pt-N coordination-driven self-assembled supramolecular polygons (triangles and rectangles) has been achieved using stable (1)H/(2)D isotope labeling of the pyridyl donors and electrospray ionization mass spectrometry combined with NMR spectroscopy. Both the thermodynamic and kinetic aspects of such exchange processes have been established on the basis of quantitative mass spectral results. Further investigation has shown that the exchange is highly dependent on experimental conditions such as temperature, solvent, and the counteranions.

  20. Geometry directed self-selection in the coordination-driven self-assembly of irregular supramolecular polygons.

    Science.gov (United States)

    Zheng, Yao-Rong; Northrop, Brian H; Yang, Hai-Bo; Zhao, Liang; Stang, Peter J

    2009-05-01

    The self-assembly of irregular metallo-supramolecular hexagons and parallelograms has been achieved in a self-selective manner upon mixing 120 degrees unsymmetrical dipyridyl ligands with 60 degrees or 120 degrees organoplatinum acceptors in a 1:1 ratio. The polygons have been characterized using (31)P and (1)H multinuclear NMR spectroscopy and electrospray ionization mass spectrometry (ESI-MS) as well as X-ray crystallography. Geometric features of the molecular subunits direct the self-selection process, which is supported by molecular force field computations.

  1. Building new discrete supramolecular assemblies through the interaction of iso-tellurazole N-oxides with Lewis acids and bases.

    Science.gov (United States)

    Ho, Peter C; Jenkins, Hilary A; Britten, James F; Vargas-Baca, Ignacio

    2017-10-13

    The supramolecular macrocycles spontaneously assembled by iso-tellurazole N-oxides are stable towards Lewis bases as strong as N-heterocyclic carbenes (NHC) but readily react with Lewis acids such as BR 3 (R = Ph, F). The electron acceptor ability of the tellurium atom is greatly enhanced in the resulting O-bonded adducts, which consequently enables binding to a variety of Lewis bases that includes acetonitrile, 4-dimethylaminopyridine, 4,4'-bipyridine, triphenyl phosphine, a N-heterocyclic carbene and a second molecule of iso-tellurazole N-oxide.

  2. Proton Mediated Chemistry and Catalysis in a Self-Assembled Supramolecular Host

    Energy Technology Data Exchange (ETDEWEB)

    Pluth, Michael; Bergman, Robert; Raymond, Kenneth

    2009-04-10

    Synthetic supramolecular host assemblies can impart unique reactivity to encapsulated guest molecules. Synthetic host molecules have been developed to carry out complex reactions within their cavities, despite the fact that they lack the type of specifically tailored functional groups normally located in the analogous active sites of enzymes. Over the past decade, the Raymond group has developed a series of self-assembled supramolecules and the Bergman group has developed and studied a number of catalytic transformations. In this Account, we detail recent collaborative work between these two groups, focusing on chemical catalysis stemming from the encapsulation of protonated guests and expanding to acid catalysis in basic solution. We initially investigated the ability of a water-soluble, self-assembled supramolecular host molecule to encapsulate protonated guests in its hydrophobic core. Our study of encapsulated protonated amines revealed rich host-guest chemistry. We established that self-exchange (that is, in-out guest movement) rates of protonated amines were dependent on the steric bulk of the amine rather than its basicity. The host molecule has purely rotational tetrahedral (T) symmetry, so guests with geminal N-methyl groups (and their attendant mirror plane) were effectively desymmetrized; this allowed for the observation and quantification of the barriers for nitrogen inversion followed by bond rotation. Furthermore, small nitrogen heterocycles, such as N-alkylaziridines, N-alkylazetidines, and N-alkylpyrrolidines, were found to be encapsulated as proton-bound homodimers or homotrimers. We further investigated the thermodynamic stabilization of protonated amines, showing that encapsulation makes the amines more basic in the cavity. Encapsulation raises the effective basicity of protonated amines by up to 4.5 pK{sub a} units, a difference almost as large as that between the moderate and strong bases carbonate and hydroxide. The thermodynamic stabilization

  3. Supramolecular ionics: electric charge partition within polymers and other non-conducting solids

    Directory of Open Access Journals (Sweden)

    FERNANDO GALEMBECK

    2001-12-01

    Full Text Available Electrostatic phenomena in insulators have been known for the past four centuries, but many related questions are still unanswered, for instance: which are the charge-bearing species in an electrified organic polymer, how are the charges spatially distributed and which is the contribution of the electrically charged domains to the overall polymer properties? New scanning probe microscopies were recently introduced, and these are suitable for the mapping of electric potentials across a solid sample thus providing some answers for the previous questions. In this work, we report results obtained with two of these techniques: scanning electric potential (SEPM and electric force microscopy (EFM. These results were associated to images acquired by using analytical electron microscopy (energy-loss spectroscopy imaging in the transmission electron microscope, ESI-TEM for colloid polymer samples. Together, they show domains with excess electric charges (and potentials extending up to hundreds of nanometers and formed by large clusters of cations or anions, reaching supramolecular dimensions. Domains with excess electric charge were also observed in thermoplastics as well as in silica, polyphosphate and titanium oxide particles. In the case of thermoplastics, the origin of the charges is tentatively assigned to their tribochemistry, oxidation followed by segregation or the Mawell-Wagner-Sillars and Costa Ribeiro effects.A eletrificação de sólidos é conhecida há quatro séculos, mas há muitas questões importantes sobre este assunto, ainda não respondidas: por exemplo, quais são as espécies portadoras de cargas em um polímero isolante eletrificado, como estas cargas estão espacialmente distribuídas e qual é a contribuição destas cargas para as propriedades do polímero? Técnicas microscópicas introduzidas recentemente são apropriadas para o mapeamento de potenciais elétricos ao longo de uma superfície sólida, portanto podem responder a

  4. Phthalocyanine-nanocarbon ensembles: from discrete molecular and supramolecular systems to hybrid nanomaterials.

    Science.gov (United States)

    Bottari, Giovanni; de la Torre, Gema; Torres, Tomas

    2015-04-21

    Phthalocyanines (Pcs) are macrocyclic and aromatic compounds that present unique electronic features such as high molar absorption coefficients, rich redox chemistry, and photoinduced energy/electron transfer abilities that can be modulated as a function of the electronic character of their counterparts in donor-acceptor (D-A) ensembles. In this context, carbon nanostructures such as fullerenes, carbon nanotubes (CNTs), and, more recently, graphene are among the most suitable Pc "companions". Pc-C60 ensembles have been for a long time the main actors in this field, due to the commercial availability of C60 and the well-established synthetic methods for its functionalization. As a result, many Pc-C60 architectures have been prepared, featuring different connectivities (covalent or supramolecular), intermolecular interactions (self-organized or molecularly dispersed species), and Pc HOMO/LUMO levels. All these elements provide a versatile toolbox for tuning the photophysical properties in terms of the type of process (photoinduced energy/electron transfer), the nature of the interactions between the electroactive units (through bond or space), and the kinetics of the formation/decay of the photogenerated species. Some recent trends in this field include the preparation of stimuli-responsive multicomponent systems with tunable photophysical properties and highly ordered nanoarchitectures and surface-supported systems showing high charge mobilities. A breakthrough in the Pc-nanocarbon field was the appearance of CNTs and graphene, which opened a new avenue for the preparation of intriguing photoresponsive hybrid ensembles showing light-stimulated charge separation. The scarce solubility of these 1-D and 2-D nanocarbons, together with their lower reactivity with respect to C60 stemming from their less strained sp(2) carbon networks, has not meant an unsurmountable limitation for the preparation of variety of Pc-based hybrids. These systems, which show improved

  5. Proton-Mediated Chemistry and Catalysis in a Self-Assembled Supramolecular Host

    International Nuclear Information System (INIS)

    Pluth, Michael; Bergman, Robert; Raymond, Kenneth

    2009-01-01

    Synthetic supramolecular host assemblies can impart unique reactivity to encapsulated guest molecules. Synthetic host molecules have been developed to carry out complex reactions within their cavities, despite the fact that they lack the type of specifically tailored functional groups normally located in the analogous active sites of enzymes. Over the past decade, the Raymond group has developed a series of self-assembled supramolecules and the Bergman group has developed and studied a number of catalytic transformations. In this Account, we detail recent collaborative work between these two groups, focusing on chemical catalysis stemming from the encapsulation of protonated guests and expanding to acid catalysis in basic solution. We initially investigated the ability of a water-soluble, self-assembled supramolecular host molecule to encapsulate protonated guests in its hydrophobic core. Our study of encapsulated protonated amines revealed rich host-guest chemistry. We established that self-exchange (that is, in-out guest movement) rates of protonated amines were dependent on the steric bulk of the amine rather than its basicity. The host molecule has purely rotational tetrahedral (T) symmetry, so guests with geminal N-methyl groups (and their attendant mirror plane) were effectively desymmetrized; this allowed for the observation and quantification of the barriers for nitrogen inversion followed by bond rotation. Furthermore, small nitrogen heterocycles, such as N-alkylaziridines, N-alkylazetidines, and N-alkylpyrrolidines, were found to be encapsulated as proton-bound homodimers or homotrimers. We further investigated the thermodynamic stabilization of protonated amines, showing that encapsulation makes the amines more basic in the cavity. Encapsulation raises the effective basicity of protonated amines by up to 4.5 pK a units, a difference almost as large as that between the moderate and strong bases carbonate and hydroxide. The thermodynamic stabilization of

  6. Thermal and oxidative stability of the Ocimum basilicum L. essential oil/β-cyclodextrin supramolecular system

    Directory of Open Access Journals (Sweden)

    Daniel I. Hădărugă

    2014-11-01

    Full Text Available Ocimum basilicum L. essential oil and its β-cyclodextrin (β-CD complex have been investigated with respect to their stability against the degradative action of air/oxygen and temperature. This supramolecular system was obtained by a crystallization method in order to achieve the equilibrium of complexed–uncomplexed volatile compounds in an ethanol/water solution at 50 °C. Both the raw essential oil and its β-CD complex have been subjected to thermal and oxidative degradation conditions in order to evaluate the protective capacity of β-CD. The relative concentration of the O. basilicum L. essential oil compounds, as determined by GC–MS, varies accordingly with their sensitivity to the thermal and/or oxidative degradation conditions imposed. Furthermore, the relative concentration of the volatile O. basilicum L. compounds found in the β-CD complex is quite different in comparison with the raw material. An increase of the relative concentration of linalool oxide from 0.3% to 1.1%, in addition to many sesquiterpene oxides, has been observed. β-CD complexation of the O. basilicum essential oil modifies the relative concentration of the encapsulated volatile compounds. Thus, linalool was better encapsulated in β-CD, while methylchavicol (estragole was encapsulated in β-CD at a concentration close to that of the raw essential oil. Higher relative concentrations from the degradation of the oxygenated compounds such as linalool oxide and aromadendren oxide were determined in the raw O. basilicum L. essential oil in comparison with the corresponding β-CD complex. For the first time, the protective capability of natural β-CD for labile basil essential oil compounds has been demonstrated.

  7. Thermal and oxidative stability of the Ocimum basilicum L. essential oil/β-cyclodextrin supramolecular system.

    Science.gov (United States)

    Hădărugă, Daniel I; Hădărugă, Nicoleta G; Costescu, Corina I; David, Ioan; Gruia, Alexandra T

    2014-01-01

    Ocimum basilicum L. essential oil and its β-cyclodextrin (β-CD) complex have been investigated with respect to their stability against the degradative action of air/oxygen and temperature. This supramolecular system was obtained by a crystallization method in order to achieve the equilibrium of complexed-uncomplexed volatile compounds in an ethanol/water solution at 50 °C. Both the raw essential oil and its β-CD complex have been subjected to thermal and oxidative degradation conditions in order to evaluate the protective capacity of β-CD. The relative concentration of the O. basilicum L. essential oil compounds, as determined by GC-MS, varies accordingly with their sensitivity to the thermal and/or oxidative degradation conditions imposed. Furthermore, the relative concentration of the volatile O. basilicum L. compounds found in the β-CD complex is quite different in comparison with the raw material. An increase of the relative concentration of linalool oxide from 0.3% to 1.1%, in addition to many sesquiterpene oxides, has been observed. β-CD complexation of the O. basilicum essential oil modifies the relative concentration of the encapsulated volatile compounds. Thus, linalool was better encapsulated in β-CD, while methylchavicol (estragole) was encapsulated in β-CD at a concentration close to that of the raw essential oil. Higher relative concentrations from the degradation of the oxygenated compounds such as linalool oxide and aromadendren oxide were determined in the raw O. basilicum L. essential oil in comparison with the corresponding β-CD complex. For the first time, the protective capability of natural β-CD for labile basil essential oil compounds has been demonstrated.

  8. Interactions and Supramolecular Organization of Sulfonated Indigo and Thioindigo Dyes in Layered Hydroxide Hosts.

    Science.gov (United States)

    Costa, Ana L; Gomes, Ana C; Pereira, Ricardo C; Pillinger, Martyn; Gonçalves, Isabel S; Pineiro, Marta; Seixas de Melo, J Sérgio

    2018-01-09

    Supramolecularly organized host-guest systems have been synthesized by intercalating water-soluble forms of indigo (indigo carmine, IC) and thioindigo (thioindigo-5,5'-disulfonate, TIS) in zinc-aluminum-layered double hydroxides (LDHs) and zinc-layered hydroxide salts (LHSs) by coprecipitation routes. The colors of the isolated powders were dark blue for hybrids containing only IC, purplish blue or dark lilac for cointercalated samples containing both dyes, and ruby/wine for hybrids containing only TIS. The as-synthesized and thermally treated materials were characterized by Fourier transform infrared, Fourier transform Raman, and nuclear magnetic resonance spectroscopies, powder X-ray diffraction, scanning electron microscopy, and elemental and thermogravimetric analyses. The basal spacings found for IC-LDH, TIS-LDH, IC-LHS, and TIS-LHS materials were 21.9, 21.05, 18.95, and 21.00 Å, respectively, with intermediate spacings being observed for the cointercalated samples that either decreased (LDHs) or increased (LHSs) with increasing TIS content. UV-visible and fluorescence spectroscopies (steady-state and time-resolved) were used to probe the molecular distribution of the immobilized dyes. The presence of aggregates together with the monomer units is suggested for IC-LDH, whereas for TIS-LDH, IC-LHS, and TIS-LHS, the dyes are closer to the isolated situation. Accordingly, while emission from the powder H 2 TIS is strongly quenched, an increment in the emission of about 1 order of magnitude was observed for the TIS-LDH/LHS hybrids. Double-exponential fluorescence decays were obtained and associated with two monomer species interacting differently with cointercalated water molecules. The incorporation of both TIS and IC in the LDH and LHS hosts leads to an almost complete quenching of the fluorescence, pointing to a very efficient energy transfer process from (fluorescent) TIS to (nonfluorescent) IC.

  9. Supramolecular tetracluster-cobalt porphyrin: a four-electron transfer catalyst for dioxygen reduction

    International Nuclear Information System (INIS)

    Winnischofer, Herbert; Otake, Vesper Yoshiyuki; Dovidauskas, Sergio; Nakamura, Marcelo; Toma, Henrique Eisi; Araki, Koiti

    2004-01-01

    Electrocatalysis by CoTCP {CoTCP meso-tetrakis(4-pyridyl)porphynatocobalt(III)} coordinated to four [Ru 3 (μ 3 -O)(μ 2 -CH 3 CO 2 ) 6 (py) 2 ] + complexes in the four-electron reduction of dioxygen, has been unequivocally demonstrated in this work by using two types of electrostatically assembled films of CoTCP and anionic zinc or free-base meso-tetrakis(4-sulfonatophenyl)porphyrins (ZnTPPS or H 2 TPPS), as well as, by employing different electrode materials. An enhanced electrocatalytic activity has been observed, in spite of the fact that the typical bis-coordination of dioxygen to two cobalt porphyrin sites is precluded in such CoTCP/ZnTPPS or CoTCP/H 2 TPPS bilayered films. In addition, negligible ring currents have been observed in ring-disk voltammetry measurements, yielding straight Levich and Koutecky-Levich plots, whose slopes approached the theoretical 4e - curve in air, or in O 2 saturated solutions (pH 3-5). The use of gold instead of glassy carbon (GC) electrodes has not also significantly perturbed the mechanism. By ruling out any influence from the electrode materials, a well known critical point in the catalysis by cobalt porphyrins, the results have shown that CoTCP is acting as a four-electron transfer catalyst for dioxygen reduction. Also, by excluding the possibility of bis-coordination of dioxygen, it was shown that the electronic and supramolecular effects exerted by the peripheral ruthenium cluster complexes should be triggering the four-electron catalytic activity of the cobalt porphyrin center

  10. On the kinetics of body versus end evaporation and addition of supramolecular polymers.

    Science.gov (United States)

    Tiwari, Nitin S; van der Schoot, Paul

    2017-06-01

    The kinetics of the self-assembly of supramolecular polymers is dictated by how monomers, dimers, trimers etc., attach to and detach from each other. It is for this reasons that researchers have proposed a plethora of pathways to explain the kinetics of various self-assembling supramolecules, including sulfur, linear micelles, living polymers and protein fibrils. Recent observations hint at the importance of a hitherto ignored molecular aggregation pathway that we refer to as "body evaporation and addition". In this pathway, monomers can enter at or dissociate from any point along the backbone of the polymer. In this paper, we compare predictions for the well-established end evaporation and addition pathway with those that we obtained for the newly proposed body evaporation and addition model. We quantify the lag time, characteristic of nucleated reversible polymerisation, in terms of the time it takes to obtain half of the steady-state polymerised fraction and the apparent growth rate at that point, and obtain power laws for both as a function of the total monomer concentration. We find, perhaps not entirely unexpectedly, that the body evaporation and addition pathway speeds up the relaxation of the polymerised monomeric mass relative to that of the end evaporation and addition. However, the presence of the body evaporation and addition pathway does not affect the dependence of the lag time on the total monomer concentration and it remains the same as that for the case of end evaporation and addition. The scaling of the lag time with the forward rate is different for the two models, suggesting that they may be distinguished experimentally.

  11. Graphene–cyclodextrin–cytochrome c layered assembly with improved electron transfer rate and high supramolecular recognition capability

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Cheng-Bin; Guo, Cong-Cong; Jiang, Dan; Tang, Qian, E-mail: qiantang@swu.edu.cn; Liu, Chang-Hua; Ma, Xue-Bing

    2014-06-01

    This study aimed to develop a new graphene-based layered assembly, named graphene–cyclodextrin–cytochrome c with improved electron transfer rate. This assembly has combined high conductivity of graphene nanosheets (GNs), selectively binding properties and electronegativity of cyclodextrins (CDs), as well as electropositivity of cytochrome c (Cyt c). This assembly can also mimic the confined environments of the intermembrane space of mitochondria. A β-cyclodextrin (β-CD) functionalized GN (GN–CD) assembly was initially prepared by a simple wet-chemical strategy, i.e., in situ thermal reduction of graphene oxide with hydrazine hydrate in the presence of β-CD. Cyt c was then intercalated to the GN–CD assembly to form a layered self-assembled structure, GN–CD–Cyt c, through electrostatic interaction. Compared with GNs and GN–CD, GN–CD–Cyt c assembly displayed improved electron transfer rate and high supramolecular recognition capability toward six probe molecules. - Highlights: • A new tertiary layered assembly named GN–CD–Cyt c was prepared. • Compared with GNs and GN–CD, GN–CD–Cyt c shows improved electron transfer rate. • GN–CD–Cyt c displays high supramolecular recognition capability.

  12. Self-assembled materials and supramolecular chemistry within microfluidic environments: from common thermodynamic states to non-equilibrium structures.

    Science.gov (United States)

    Sevim, S; Sorrenti, A; Franco, C; Furukawa, S; Pané, S; deMello, A J; Puigmartí-Luis, J

    2018-05-01

    Self-assembly is a crucial component in the bottom-up fabrication of hierarchical supramolecular structures and advanced functional materials. Control has traditionally relied on the use of encoded building blocks bearing suitable moieties for recognition and interaction, with targeting of the thermodynamic equilibrium state. On the other hand, nature leverages the control of reaction-diffusion processes to create hierarchically organized materials with surprisingly complex biological functions. Indeed, under non-equilibrium conditions (kinetic control), the spatio-temporal command of chemical gradients and reactant mixing during self-assembly (the creation of non-uniform chemical environments for example) can strongly affect the outcome of the self-assembly process. This directly enables a precise control over material properties and functions. In this tutorial review, we show how the unique physical conditions offered by microfluidic technologies can be advantageously used to control the self-assembly of materials and of supramolecular aggregates in solution, making possible the isolation of intermediate states and unprecedented non-equilibrium structures, as well as the emergence of novel functions. Selected examples from the literature will be used to confirm that microfluidic devices are an invaluable toolbox technology for unveiling, understanding and steering self-assembly pathways to desired structures, properties and functions, as well as advanced processing tools for device fabrication and integration.

  13. Supramolecular Assembly of Comb-like Macromolecules Induced by Chemical Reactions that Modulate the Macromolecular Interactions In Situ.

    Science.gov (United States)

    Xia, Hongwei; Fu, Hailin; Zhang, Yanfeng; Shih, Kuo-Chih; Ren, Yuan; Anuganti, Murali; Nieh, Mu-Ping; Cheng, Jianjun; Lin, Yao

    2017-08-16

    Supramolecular polymerization or assembly of proteins or large macromolecular units by a homogeneous nucleation mechanism can be quite slow and require specific solution conditions. In nature, protein assembly is often regulated by molecules that modulate the electrostatic interactions of the protein subunits for various association strengths. The key to this regulation is the coupling of the assembly process with a reversible or irreversible chemical reaction that occurs within the constituent subunits. However, realizing this complex process by the rational design of synthetic molecules or macromolecules remains a challenge. Herein, we use a synthetic polypeptide-grafted comb macromolecule to demonstrate how the in situ modulation of interactions between the charged macromolecules affects their resulting supramolecular structures. The kinetics of structural formation was studied and can be described by a generalized model of nucleated polymerization containing secondary pathways. Basic thermodynamic analysis indicated the delicate role of the electrostatic interactions between the charged subunits in the reaction-induced assembly process. This approach may be applicable for assembling a variety of ionic soft matters that are amenable to chemical reactions in situ.

  14. Chitosan supramolecularly cross linked with trimesic acid - Facile synthesis, characterization and evaluation of adsorption potential for chromium(VI).

    Science.gov (United States)

    Bhatt, Ronak; Sreedhar, B; Padmaja, P

    2017-11-01

    A facile synthesis of Chitosan Supramolecularly cross-linked with Trimesic Acid (CTMA) is reported in this work. The adsorption potential of CTMA for removal of hexavalent chromium was evaluated and the influence of pH, temperature, contact time and adsorbent dose on the adsorption process was investigated. The experimental results showed that CTMA could efficiently adsorb Cr 6+ and partially reduce it to the less toxic Cr 3+ state. The maximum adsorption capacity of CTMA for Cr 6+ was found to be 129.53mg/g at pH 2.0. CTMA and chromium loaded CTMA were characterised by FT-IR, Raman, TGA-DSC, SEM-EDX, XRD, ESR and XPS spectroscopic techniques. Chitosan was observed to be cross- linked with TMA via ionic, hydrogen bonding and pi-pi supramolecular interactions while adsorption of chromium onto CTMA was by electrostatic forces and hydrogen bonding. From the observed results it was evident that CTMA was successfully applied for simultaneous removal of chromium, lead and iron from chrome plating effluent. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. From fundamental supramolecular chemistry to self-assembled nanomaterials and medicines and back again - how Sam inspired SAMul.

    Science.gov (United States)

    Smith, David K

    2018-05-08

    This feature article provides a personal insight into the research from my group over the past 10 years. In particular, the article explains how, inspired in 2005 by meeting my now-husband, Sam, who had cystic fibrosis, and who in 2011 went on to have a double lung transplant, I took an active decision to follow a more applied approach to some of our research, attempting to use fundamental supramolecular chemistry to address problems of medical interest. In particular, our strategy uses self-assembly to fabricate biologically-active nanosystems from simple low-molecular-weight building blocks. These systems can bind biological polyanions in highly competitive conditions, allowing us to approach applications in gene delivery and coagulation control. In the process, however, we have also developed new fundamental principles such as self-assembled multivalency (SAMul), temporary 'on-off' multivalency, and adaptive/shape-persistent multivalent binding. By targeting materials with applications in drug formulation and tissue engineering, we have discovered novel self-assembling low-molecular-weight hydrogelators based on the industrially-relevant dibenzylidenesorbitol framework and developed innovative approaches to spatially-resolved gels and functional multicomponent hybrid hydrogels. In this way, taking an application-led approach to research has also delivered significant academic value and conceptual advances. Furthermore, beginning to translate fundamental supramolecular chemistry into real-world applications, starts to demonstrate the power of this approach, and its potential to transform the world around us for the better.

  16. Effect of intermolecular dipole-dipole interactions on interfacial supramolecular structures of C3-symmetric hexa-peri-hexabenzocoronene derivatives.

    Science.gov (United States)

    Mu, Zhongcheng; Shao, Qi; Ye, Jun; Zeng, Zebing; Zhao, Yang; Hng, Huey Hoon; Boey, Freddy Yin Chiang; Wu, Jishan; Chen, Xiaodong

    2011-02-15

    Two-dimensional (2D) supramolecular assemblies of a series of novel C(3)-symmetric hexa-peri-hexabenzocoronene (HBC) derivatives bearing different substituents adsorbed on highly oriented pyrolytic graphite were studied by using scanning tunneling microscopy at a solid-liquid interface. It was found that the intermolecular dipole-dipole interactions play a critical role in controlling the interfacial supramolecular assembly of these C(3)-symmetric HBC derivatives at the solid-liquid interface. The HBC molecule bearing three -CF(3) groups could form 2D honeycomb structures because of antiparallel dipole-dipole interactions, whereas HBC molecules bearing three -CN or -NO(2) groups could form hexagonal superstructures because of a special trimeric arrangement induced by dipole-dipole interactions and weak hydrogen bonding interactions ([C-H···NC-] or [C-H···O(2)N-]). Molecular mechanics and dynamics simulations were performed to reveal the physics behind the 2D structures as well as detailed functional group interactions. This work provides an example of how intermolecular dipole-dipole interactions could enable fine control over the self-assembly of disklike π-conjugated molecules.

  17. Supramolecular "Big Bang" in a Single-Ionic Surfactant/Water System Driven by Electrostatic Repulsion: From Vesicles to Micelles.

    Science.gov (United States)

    Leclercq, Loïc; Bauduin, Pierre; Nardello-Rataj, Véronique

    2017-04-11

    In aqueous solution, dimethyldi-n-octylammonium chloride, [DiC 8 ][Cl], spontaneously forms dimers at low concentrations (1-10 mM) to decrease the strength of the hydrophobic-water contact. Dimers represent ideal building blocks for the abrupt edification of vesicles at 10 mM. These vesicles are fully characterized by dynamic and static light scattering, self-diffusion nuclear magnetic resonance, and freeze-fracture transmission electron microscopy. An increase in concentration leads to electrostatic repulsion between vesicles that explode into small micelles at 30 mM. These transitions are detected by means of surface tension, conductivity, and solubility of hydrophobic solutes as well as by isothermal titration microcalorimetry. These unusual supramolecular transitions emerge from the surfactant chemical structure that combines two contradictory features: (i) the double-chain structure tending to form low planar aggregates with low water solubility and (ii) the relatively short chains giving high hydrophilicity. The well-balanced hydrophilic-hydrophobic character of [DiC 8 ][Cl] is then believed to be at the origin of the unusual supramolecular sequence offering new opportunities for drug delivery systems.

  18. Graphene–cyclodextrin–cytochrome c layered assembly with improved electron transfer rate and high supramolecular recognition capability

    International Nuclear Information System (INIS)

    Gong, Cheng-Bin; Guo, Cong-Cong; Jiang, Dan; Tang, Qian; Liu, Chang-Hua; Ma, Xue-Bing

    2014-01-01

    This study aimed to develop a new graphene-based layered assembly, named graphene–cyclodextrin–cytochrome c with improved electron transfer rate. This assembly has combined high conductivity of graphene nanosheets (GNs), selectively binding properties and electronegativity of cyclodextrins (CDs), as well as electropositivity of cytochrome c (Cyt c). This assembly can also mimic the confined environments of the intermembrane space of mitochondria. A β-cyclodextrin (β-CD) functionalized GN (GN–CD) assembly was initially prepared by a simple wet-chemical strategy, i.e., in situ thermal reduction of graphene oxide with hydrazine hydrate in the presence of β-CD. Cyt c was then intercalated to the GN–CD assembly to form a layered self-assembled structure, GN–CD–Cyt c, through electrostatic interaction. Compared with GNs and GN–CD, GN–CD–Cyt c assembly displayed improved electron transfer rate and high supramolecular recognition capability toward six probe molecules. - Highlights: • A new tertiary layered assembly named GN–CD–Cyt c was prepared. • Compared with GNs and GN–CD, GN–CD–Cyt c shows improved electron transfer rate. • GN–CD–Cyt c displays high supramolecular recognition capability

  19. Structural transition in aqueous lipid/bile salt [DPPC/NaDC] supramolecular aggregates: SANS and DLS study

    International Nuclear Information System (INIS)

    Kiselev, M.A.; Janich, M.; Hildebrand, A.; Strunz, P.; Neubert, R.H.H.; Lombardo, D.

    2013-01-01

    Highlights: • Self-assembly in model DPPC lipids and NaDC bile salt by SANS and DLS experiments. • Bile salt creates structural interference against cohesive tendency of DPPC bilayers. • NaDC steric interactions cause transition toward different supramolecular structures. - Abstract: Small angle neutron scattering (SANS) and dynamic light scattering (DLS) were used to study different aggregation states in sodium deoxycholate (NaDC)-phosphatidylcholine systems at T = 60 °C. Size and shape of the aggregates investigated as a function of the NaDC bile salt concentration (at the constant DPPC concentration of 6 mM) indicate a strong dependence of the size and morphology of the generated aggregates on the relative amount of NaDC bile salt. More specifically large occupied area of the bile salt induces a steric interaction which promotes the transition toward a variety of supramolecular structures ranging from ellipsoidal vesicles, ribbon-like structures, up to final spherical mixed micelles at the large amount of bile salt of 10 mM NaDC. The findings of the obtained results give important insight for understanding the formation of different topologies in aqueous lipid–bile salt mixtures as well as stimulate new routes for liposome reconstitution–solubilisation processes suitable for technological applications

  20. The efficacy of the supramolecular complexes of niclosamide obtained by mechanochemical technology and targeted delivery against cestode infection of animals.

    Science.gov (United States)

    Arkhipov, Ivan A; Sadov, Konstantin M; Limova, Yulia V; Sadova, Alexandra K; Varlamova, Anastasiya I; Khalikov, Salavat S; Dushkin, Alexandr V; Chistyachenko, Yulia S

    2017-11-15

    Niclosamide is an anthelmintic that is widely used to treat cestode infection of animals. The efficacy of the supramolecular complexes of niclosamide obtained by mechanochemical technology and targeted delivery was studied in hymenolepiosis of mice and monieziosis of sheep. The efficacy of new substances of niclosamide with polyvinylpyrrolidone polymer in different ratios (1:10; 1:5; 1:2) was determined by the results of helminthological necropsy of the small intestine of sheep and mice. Pre-treatment eggs per gram (EPG) were not significantly different (P>0.1) among groups. The controlled test was used to evaluate the efficacy. A high efficacy (>95% efficacy) of the supramolecular complexes of niclosamide with PVP (SCoNwPVP) was shown in different ratios (1:10; 1:5 and 1:2) at a dose of 20mg/kg of body weight at oral administration against Hymenolepis nana in mice and Moniezia expansa in sheep. Whereas the basic drug - substance of niclosamide was effective at a dose of 100mg/kg of b/w. No adverse effects of the drugs on animal health were detected during the study. Copyright © 2017 Elsevier B.V. All rights reserved.