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Sample records for terphenyls

  1. Vacuum UV Polarization Spectroscopy of p-Terphenyl

    DEFF Research Database (Denmark)

    Nguyen, Duy Duc; Jones, Nykola C.; Hoffmann, Søren Vrønning

    2018-01-01

    p-Terphenyl is used as a component in a variety of optical devices. In this investigation, the electronic transitions of p-terphenyl are investigated by synchrotron radiation linear dichroism (SRLD) spectroscopy in the range 30000 – 58000 cm–1 (330 – 170 nm) on molecular samples aligned in stretc...

  2. Studies on Structural, Optical, Thermal and Electrical Properties of Perylene-Doped p-terphenyl Luminophors.

    Science.gov (United States)

    Desai, Netaji K; Mahajan, Prasad G; Bhopate, Dhanaji P; Dalavi, Dattatray K; Kamble, Avinash A; Gore, Anil H; Dongale, Tukaram D; Kolekar, Govind B; Patil, Shivajirao R

    2017-10-02

    A simple solid state reaction technique was employed for the preparation of polycrystalline luminophors of p-terphenyl containing different amounts of perylene followed by spectral characterization techniques viz. XRD, SEM, TGA-DSC, UV-Visible spectroscopy, thermo-electrical conductivity, fluorescence spectroscopy, fluorescence life time spectroscopy and temperature dependent fluorescence. X-ray diffraction profiles of the doped p-terphenyl reveal well-defined and sharp peaks indicate homogeneity and crystallinity. The SEM micrograph of pure p-terphenyl exhibit flakes like grains and then compact and finally gets separately with perylene amounts. The observed results indicate that closed packed crystal structures of doped p-terphenyl during crystal formation. The band gaps estimated from UV-visible spectroscopy decreased from 5.20 to 4.10 eV, while thermo-electrical conductivity increases with perylene content. The fluorescence spectra showed partial quenching of p-terphenyl fluorescence and simultaneously sensitization of perylene fluorescence at the excitation wavelength of p-terphenyl (290 nm) due to excitation energy transfer from p-terphenyl to perylene. The observed sensitization results are in harmony with intense blue color seen in fluorescence microscopy images and has high demand in scintillation process.

  3. Terrestrins A-G: p-terphenyl derivatives from the inedible mushroom Thelephora terrestris.

    Science.gov (United States)

    Radulović, Niko; Quang, Dang Ngoc; Hashimoto, Toshihiro; Nukada, Makiko; Asakawa, Yoshinori

    2005-05-01

    Seven p-terphenyl derivatives named terrestrins A-G together with three known ganbajunin B, thelephantins F and H, were isolated from the methanol extract of fruiting bodies of the Japanese inedible mushroom Thelephora terrestris (Thelephoraceae). Their structures were elucidated by means of high-resolution MS, 2D NMR, IR and UV spectroscopy, and X-ray crystallographic analysis.

  4. Self-assembly of aromatic-derivatized amphiphiles: Phenyl, biphenyl, and terphenyl fatty acids and phospholipids

    Energy Technology Data Exchange (ETDEWEB)

    Geiger, H.C.; Perlstein, J.; Lachicotte, R.J.; Wyrozebski, K.; Whitten, D.G. [Univ. of Rochester, NY (United States)]|[Los Alamos National Lab., NM (United States). Chemical Science and Technology Div.

    1999-08-17

    This paper reports the synthesis of a series of amphiphiles (fatty acids and phosphatidylcholine derivatives) containing phenyl, biphenyl, and terphenyl chromophores inserted in the hydrocarbon chain and a study of their self-assembly in Langmuir-Blodgett films and aqueous dispersions. As observed and reported earlier for amphiphiles containing trans-stilbene, styrylthiophene, or azobenzene chromophores, several of the biphenyl and terphenyl derivatives show strong evidence of ground state association to form H aggregates characterized by a blue shift in absorption and a structured, red-shifted fluorescence. The phenyl amphiphiles show different behavior, suggesting that, even for pure films or bilayers, there is very little or no ground state association. For the biphenyl and terphenyl phospholipids, aqueous suspensions obtained by sonication are closed bilayer vesicles similar in size to those formed from the corresponding saturated phospholipids. The overall results of the present study indicate that biphenyl and terphenyl amphiphiles undergo aggregation processes to form compact arrays formally similar to those observed with stilbenen tolan, azobenzene, and squaraine derivatives but that the aromatic-aromatic interactions are considerably weaker than those for the more extended aromatics and lead to less distortion of the assembly structure.

  5. Multistep Synthesis of a Terphenyl Derivative Showcasing the Diels-Alder Reaction

    Science.gov (United States)

    Davie, Elizabeth A. Colby

    2015-01-01

    An adaptable multistep synthesis project designed for the culmination of a second-year organic chemistry laboratory course is described. The target compound is a terphenyl derivative that is an intermediate in the synthesis of compounds used in organic light-emitting devices. Students react a conjugated diene with dimethylacetylene dicarboxylate…

  6. Comparative study of neutron and gamma-ray pulse shape discrimination of anthracene, stilbene, and p-terphenyl

    Energy Technology Data Exchange (ETDEWEB)

    Yanagida, Takayuki, E-mail: yanagida@lsse.kyutech.ac.jp [Kyushu Institute of Technology, 2-4 Hibikino, Wakamatsu, Kitakyushu, Fukuoka 808-0196 (Japan); Watanabe, Kenichi [Nagoya University, Furocho, Chikusa, Nagoya 464-8603 (Japan); Fujimoto, Yutaka [Kyushu Institute of Technology, 2-4 Hibikino, Wakamatsu, Kitakyushu, Fukuoka 808-0196 (Japan)

    2015-06-01

    Solid state organic scintillators, such as anthracene, stilbene, and p-terphenyl were investigated on their basic scintillation properties and neutron–gamma discrimination capabilities. Scintillation wavelengths under X-ray irradiation of anthracene, stilbene, and p-terphenyl were 445–525, 400–500, and 350–450 nm, respectively. Scintillation light yields of anthracene, stilbene, and p-terphenyl under {sup 137}Cs gamma-ray irradiation were 20100, 16000, and 19400 ph/MeV, respectively. Neutron and gamma-ray events discrimination capabilities were examined and anthracene exhibited the best figure of merit among three organic scintillators.

  7. Ethyl 4,4''-Difluoro-5'-hydroxy-1,1':3',1''-terphenyl-4'-carboxylate

    Directory of Open Access Journals (Sweden)

    Badiadka Narayana

    2011-11-01

    Full Text Available A simple and novel route for the synthesis of new terphenyl derivative as well as oxidative aromatization of α,β-unsaturated cyclohexenone to the corresponding phenol derivative is developed. The present work involves the condensation of ethylacetoacetate with 4,4'-difluoro chalcone followed by the aromatization using chloramine-T in acetic acid to yield the title compound (3. The synthesized compound (3 is well characterized by IR, NMR, LCMS and elemental analysis.

  8. Dynamics of a molecular glass former: Energy landscapes for diffusion in ortho-terphenyl

    Science.gov (United States)

    Niblett, S. P.; de Souza, V. K.; Stevenson, J. D.; Wales, D. J.

    2016-07-01

    Relaxation times and transport processes of many glass-forming supercooled liquids exhibit a super-Arrhenius temperature dependence. We examine this phenomenon by computer simulation of the Lewis-Wahnström model for ortho-terphenyl. We propose a microscopic definition for a single-molecule cage-breaking transition and show that, when correlation behaviour is taken into account, these rearrangements are sufficient to reproduce the correct translational diffusion constants over an intermediate temperature range in the supercooled regime. We show that super-Arrhenius behaviour can be attributed to increasing negative correlation in particle movement at lower temperatures and relate this to the cage-breaking description. Finally, we sample the potential energy landscape of the model and show that it displays hierarchical ordering. Substructures in the landscape, which may correspond to metabasins, have boundaries defined by cage-breaking transitions. The cage-breaking formulation provides a direct link between the potential energy landscape and macroscopic diffusion behaviour.

  9. New p-terphenyls from the endophytic fungus Aspergillus sp. YXf3.

    Science.gov (United States)

    Yan, Wei; Wuringege; Li, Sui-Jun; Guo, Zhi-Kai; Zhang, Wen-Jing; Wei, Wei; Tan, Ren-Xiang; Jiao, Rui-Hua

    2017-01-01

    Five new p-terphenyls named prenylterphenyllin D (1), prenylterphenyllin E (2), 2'-O-methylprenylterphenyllin (3), 4-O-methylprenylterphenyllin (4) and 3'-O-methylterphenyllin (5) together with seven known compounds (6-12), were isolated from cultures of Aspergillus sp. YXf3. The structures of the new compounds were elucidated by extensive MS and NMR analyses. The NMR and MS data of 5 is reported for the first time, as its structure was listed in SciFinder Scholar with no associated reference. Compounds 6 and 7 were distinguished from each other on the basis of 2D NMR experiments. Compounds 1, 2, 3 and 8 showed antibacterial activities against X. oryzae pv. oryzicola Swings and E. amylovora with the same MIC values of 20μg/mL while 10 exhibited activities against E. amylovora with an MIC value of 10μg/mL. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Traceless liquid-phase synthesis of biphenyls and terphenyls using pentaerythritol as a tetrapodal soluble support.

    Science.gov (United States)

    Kim, Chul-Bae; Cho, Chul-Hee; Kim, Chang Keun; Park, Kwangyong

    2007-01-01

    Application of a novel sulfonate-based traceless multifunctional linker system using pentaerythritol as a tetrapodal soluble support was demonstrated using liquid-phase parallel and combinatorial preparation of biphenyl and terphenyl compounds. Nickel-catalyzed reactions of pentaerythritol tetrakis(arenesulfonate)s with arylmagnesium bromides generated the desired products in sufficient yields through reductive cleavage/cross-coupling of the C-S bond. Homogeneous pentaerythritol-supported reactions could be accomplished using less nucleophile with shorter reaction periods than could the corresponding heterogeneous polymer-supported reactions. This liquid-phase approach using a small polyfunctionalized support combines advantages of solution-phase and solid-phase syntheses by allowing high reactivity, high atom economy, simple isolation, and real-time monitoring of the reaction progress.

  11. Nanocalorimetry of vapor-deposited organic glasses: tris-naphthylbenzene, decalin and ortho-terphenyl

    Science.gov (United States)

    Whitaker, Katherine R.

    Physical vapor deposition can be used to prepare glasses with extraordinary properties. By optimizing the substrate temperature and deposition rate, glasses with low enthalpy, high density and high kinetic stability, as compared to the ordinary liquid-cooled glass, can be produced. The heat capacity of 'stable glasses' has been measured with conventional calorimetry, but such techniques are limited to bulk samples; the properties of more technologically relevant thin films cannot be measured. In this thesis, nanocalorimetry was utilized to measure the heat capacity of thin films of four organic glassformers: alpha,alpha,beta-tris-naphthylbenzene (alphaalphabeta-TNB),cis- and trans-decahydronaphthalene (cis- and trans -decalin) and o-terphenyl. A number of new and important results came out of the AC nanocalorimetry experiments on these molecules. alphaalphabeta-TNB thin films showed thickness dependent transformation times for films up to one micron in thickness, consistent with the work on indomethacin. This result suggested that highly suppressed bulk transformation rates are a general feature associated with the kinetics of stable glass transformation. One way glassformers can be characterized is by their fragility, or their temperature dependent behavior as Tg is approached. Decalin, the molecular glassformer with the highest reported fragility, was shown to be capable of forming stable glasses when vapor-deposited. This result implies that surface mobility, which is deemed the controlling mechanism for stable glass formation, is also present in high fragility systems. Experiments on a variety of cis/trans-decalin mixture compositions showed that vapor deposition can also be used to make stable glasses of mixtures. The ability of an array of compositions to form stable glasses is a strong argument against nanocrystals being responsible for the extraordinary properties of stable glasses. Finally, in situ experiments on o-terphenyl were able to span the range of

  12. A new route to multifunctionalized p-terphenyls and heteroaryl analogues via [5C + 1C(N)] annulation strategy.

    Science.gov (United States)

    Zhang, Lei; Liang, Fushun; Cheng, Xin; Liu, Qun

    2009-01-16

    p-Terphenyls and heteroaryl analogues including bipyridines were prepared via [5C + 1C(N)] annulation of alpha-aryl-alpha-alkenoyl ketene-(S,S)-acetals (five carbon 1,5-bielectrophilic species) with nitroethane or ammonium acetate. The reaction features mild conditions, multisubstitution, and functional group tolerance and is metal catalyst free. The present protocol provides a new alternative to the conventional methodologies for the synthesis of teraryls.

  13. Structural, optical and dynamical properties of a high birefringence laterally fluorinated terphenyl isothiocyanate

    Science.gov (United States)

    Sinha, D.; Mandal, P. K.; Dabrowski, R.

    2015-02-01

    A doubly fluorinated isothiocyanato butyl terphenyl compound exhibiting a broad range of the nematic and a narrow range of smectic phase has been investigated by X-ray, dielectric and optical methods and compared with the properties of singly and doubly fluorinated ethyl homologues to see the effect of fluorination and chain flexibility. Contrary to common perception, weak antiparallel correlation of molecules is observed in each compound both from X-ray and dielectric studies. Observed dielectric anisotropy is strong enough to ensure a driving voltage suitable for thin film transistor-based liquid crystal display. Measured splay elastic constant suggests that the present compound will exhibit the fastest response. Flip-flop mode relaxations are observed in a few hundred kHz to MHz range. All the compounds exhibit high birefringence (0.373-0.331). They also show high order parameters at low temperatures. These compounds are expected to be suitable for formulating high birefringence nematic mixtures for fast switching displays.

  14. Spectroscopic Evidence for Through-Space Arene-Sulfur-Arene Bonding Interaction in m-Terphenyl Thioether Radical Cations.

    Science.gov (United States)

    Monney, Nicolas P-A; Bally, Thomas; Yamamoto, Takuhei; Glass, Richard S

    2015-12-31

    Electronic absorption spectra and quantum chemical calculations of the radical cations of m-terphenyl tert-butyl thioethers, where the S-t-Bu bond is forced to be perpendicular to the central phenyl ring, show the occurrence of through-space [π···S···π](+) bonding interactions which lead to a stabilization of the thioether radical cations. In the corresponding methyl derivatives there is a competition between delocalization of the hole that is centered on a p-AO of the S atom into the π-system of the central phenyl ring or through space into the flanking phenyl groups, which leads to a mixture of planar and perpendicular conformations in the radical cation. Adding a second m-terphenyl tert-butyl thioether moiety does not lead to further delocalization; the spin and charge remain in one of the two halves of the radical cation. These findings have interesting implications with regard to the role of methionines as hopping stations in electron transfer through proteins.

  15. Synthesis and characterization of soluble, blue-fluorescent polyamides and polyimides containing substituted p-terphenyl as well as long aliphatic segments in the main chain

    NARCIS (Netherlands)

    Mikroyannidis, JA; Tsivgoulis, GM

    1999-01-01

    A novel class of semiflexible polyamides and polyimides bearing substituted p-terphenyl as well as long aliphatic segments in the main chain were synthesized through pyrylium salts. Characterization of polymers was accomplished by inherent viscosity, elemental analysis, FT-IR, NMR, UV-vis

  16. The Second-Order Stark Effect on the 1B2u Electronic Origin of Tetracene and Pentacene in p-Terphenyl

    NARCIS (Netherlands)

    Meyling, Jan H.; Wiersma, Douwe A.

    1973-01-01

    The electric field induced shift of the electronic origin of the lowest B2u singlet state of tetracene and pentacene in p-terphenyl at 1.8°K has been measured. From this shift we calculate the difference in polarizability of this state and the ground state along the long molecular axis to be 4.5 ±

  17. Terfestatins B and C, New p-Terphenyl Glycosides Produced by Streptomyces sp. RM-5–8

    Science.gov (United States)

    Wang, Xiachang; Reynolds, Anna R.; Elshahawi, Sherif I.; Shaaban, Khaled A.; Ponomareva, Larissa V.; Saunders, Meredith A.; Elgumati, Ibrahim S.; Zhang, Yinan; Copley, Gregory C.; Hower, James C.; Sunkara, Manjula; Morris, Andrew J.; Kharel, Madan K.; Van Lanen, Steven G.; Prendergast, Mark A.; Thorson, Jon S.

    2015-01-01

    Terfestatins B (1) and C (2), new p-terphenyls bearing a novel unsaturated hexuronic acid (4-deoxy-α-l-threo-hex-4-enopyranuronate), a unique β-d-glycosyl ester of 5-isoprenylindole-3-carboxylate (3) and the same rare sugar, and two new hygromycin precursors, were characterized as metabolites of the coal mine fire isolate Streptomyces sp. RM-5–8. EtOH damage neuroprotection assays using rat hippocampal-derived primary cell cultures with 1, 2, 3 and echoside B (a terfestatin C-3′-β-d-glucuronide from Streptomyces sp. RM-5– 8) revealed 1 as potently neuroprotective, highlighting a new potential application of the terfestatin scaffold. PMID:25961722

  18. Anomalous doping of a molecular crystal monitored with confocal fluorescence microscopy: Terrylene in a p-terphenyl crystal

    Science.gov (United States)

    Białkowska, Magda; Deperasińska, Irena; Makarewicz, Artur; Kozankiewicz, Bolesław

    2017-09-01

    Highly terrylene doped single crystals of p-terphenyl, obtained by co-sublimation of both components, showed bright spots in the confocal fluorescence images. Polarization of the fluorescence excitation spectra, blinking and bleaching, and saturation behavior allowed us to attribute them to single molecules of terrylene anomalously embedded between two neighbor layers of the host crystal, in the (a,b) plane. Such an orientation of terrylene molecules results in much more efficient absorption and collection of the fluorescence photons than in the case of previously investigated molecules embedded in the substitution sites. The above conclusion was supported by quantum chemistry calculations. We postulate that the kind of doping considered in this work should be possible in other molecular crystals where the host molecules are organized in a herringbone pattern.

  19. Stochastic theory of optically detected single-spin coherent phenomena: Evidence for non-Markovian dephasing of pentacene in p-terphenyl

    Science.gov (United States)

    Kilin, S. Ya.; Nizovtsev, A. P.; Berman, P. R.; Wrachtrup, J.; Borczyskowski, C. Von

    1997-07-01

    The optically detected coherent response of a single chromophore molecule in an organic host matrix to a microwave radiation resonant to a transition between triplet spin substates is analyzed using a model in which N independent random telegraph processes produce fluctuations of the spin transition frequency. Measurements of (i) Hahn echoes, (ii) power-broadened line shapes, (iii) transient nutation, and (iv) second-order correlation functions for single pentacene molecules in a p-terphenyl crystal are explained within the context of the model, assuming the fluctuations to be slow. The failure of the standard Bloch equations for this system is demonstrated and the effects of microwave-suppressed dephasing are discussed.

  20. Crystalline Coordination Networks of Zero-Valent Metal Centers: Formation of a 3-Dimensional Ni(0) Framework with m-Terphenyl Diisocyanides.

    Science.gov (United States)

    Agnew, Douglas W; DiMucci, Ida M; Arroyave, Alejandra; Gembicky, Milan; Moore, Curtis E; MacMillan, Samantha N; Rheingold, Arnold L; Lancaster, Kyle M; Figueroa, Joshua S

    2017-11-13

    A permanently porous, three-dimensional metal-organic material formed from zero-valent metal nodes is presented. Combination of ditopic m-terphenyl diisocyanide, [CNArMes2]2, and the d10 Ni(0) precursor Ni(COD)2, produces a porous metal-organic material featuring tetrahedral [Ni(CNArMes2)4]n structural sites. X-ray absorption spectroscopy provides firm evidence for the presence of Ni(0) centers, while gas-sorption and differential-scanning calorimetry analysis reveal the characteristics of a robust network with a micro-domain N2-adsorption profile.

  1. Pyrolytic Behaviour of the Commercial Terphenyl Mixtures. Propil OM1, OM2 and OMP; Comportamiento pirolitico de las mezclas terfenilicas comerciales. Progil OM1, OM2 y OMP

    Energy Technology Data Exchange (ETDEWEB)

    Barrera Pinero, R.; Manero Rodriguez, J.

    1963-07-01

    Statistic tests on the thermal stability of the three above mentioned materials and pure para-terphenyl, at temperatures ranging 400-470 degree centigrade, are described. Several conclusions are attained with respect to the kinetics of the pyrolysis decomposition, which was controlled according to the following steps: a) Gas evolution (hydrogen and hydrocarbons). B) Intermediate boiling compound formation, such as biphenyl, benzene.alkyl-benzenes, etc. c) high boiling compound evolution. d) Decreasing of starting material. In this way, comparative data en decomposition rate and activation energy of the pyrolysis phenomena are tabulated. (Author) 15 refs.

  2. Electronic energy transfer in tetracene-doped p-terphenyl nanoparticles: Extraordinarily high fluorescence enhancement and quenching efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Mitsui, Masaaki, E-mail: smmitsu@ipc.shizuoka.ac.jp; Kawano, Yuya

    2013-06-20

    Highlights: ► Tc/pTP-NPs at various doping ratios are produced by reprecipitation in water. ► The energy transfer in Tc/pTP-NPs is investigated. ► More than 10{sup 4}pTP donors were quenched by a single Tc acceptor. ► Efficient energy transfer is attributed to the rapid exciton diffusion in the NPs. - Abstract: A series of tetracene (Tc)-doped p-terphenyl (pTP) nanoparticles (Tc/pTP-NPs) were produced at various doping ratios by reprecipitation in water. The Tc/pTP-NPs are disk-like with a mean diameter of 75 nm and height of 7 nm, which were determined by scanning electron microscopy and atomic force microscopy, and exhibited electronic delocalization through H-type aggregation of the pTP molecules. Electronic energy transfer in the Tc/pTP-NPs was examined using steady-state and time-resolved fluorescence spectroscopy and fluorescence anisotropy experiments: pTP-NPs serve as an excellent light-harvesting nano-matrix with a large absorption coefficient that exceeds 10{sup 9} M{sup −1} cm{sup −1}. Furthermore, Stern–Volmer analysis of the donor emission was performed by changing the dopant concentration; this showed that a single Tc acceptor quenched more than 10{sup 4}pTP donors. Comparison of the experimental and theoretical energy transfer efficiencies indicated that the efficient energy transfer can be attributed to two-dimensional exciton diffusion in the host nanoparticles.

  3. Synthesis and characterization of three 2D Cd (II) coordination polymers built with terphenyl-2, 2‧, 4, 4‧-tetracarboxylate and flexible bis(imidazole)

    Science.gov (United States)

    Wang, Ji-Jiang; Tang, Long; Zhang, Mei-Li; Gao, Lou-Jun; Ren, Yi-Xia; Hou, Xiang-Yang; Fu, Feng

    2015-04-01

    Three new CdII coordination polymers, namely, {[Cd2 (L) (1, 2-bix)2(H2O)2]ṡ2H2O}n(1), [Cd2 (L) (1, 3-bix)2]n (2), and {[Cd (H2L) (1, 4-bix) (H2O)2]ṡ2H2O}n (3) [H4L = terphenyl-2, 2‧, 4, 4‧-tetracarboxylic acid, 1, n-bix = 1, n-bis(imidazol-l-ylmethyl) benzene (n = 2, 3, 4)], have been synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction, IR, thermogravimetric analysis, and fluorescent analysis. Complex 1 is a 2D wavelike network structure incorporating the dinuclear Cd2 (1, 2-bix)2 units, whereas complex 2 possesses a 2D stair-like network structure consisting of the dinuclear Cd2O2 units. Complex 3 features a 2D puckered network constructed by 1D [Cd (H2L)]n and 1D [Cd (1, 4-bix)]n chains. The results show that the structural diversity of the polymers is mainly attributed to the usage of diverse ancillary bis (imidazol-1-ylmethyl)-benzene isomers ligands. The thermal stabilities and photoluminescence behaviors were also investigated.

  4. Fluorescence quenching of 2,2'' dimethyl-p-terphenyl by carbon tetrachloride in different solvents and temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Biradar, D.S. [Department of Physics, Gulbarga University, Gulbarga 585 106, Karnataka (India); Thipperudrappa, J. [Department of Physics, BNM Institute of Technology, Bangalore 560 070 (India); Hanagodimath, S.M. [Department of Physics, Gulbarga University, Gulbarga 585 106, Karnataka (India)]. E-mail: smhmath@rediffmail.com

    2007-10-15

    The fluorescence quenching of 2,2''-dimethyl-p-terphenyl (DMT) by carbon tetrachloride by steady state in different solvents, and by transient method in benzene has been carried out at room temperature. The Stern-Volmer (SV) plot has been found to be non-linear with a positive deviation for all the solvents studied. In order to interpret these results we have invoked the ground state complex and sphere of action static quenching models. Using these models various rate parameters have been determined. The magnitudes of these parameters imply that sphere of action static quenching model agrees well with the experimental results. Hence the positive deviation in the SV plots is attributed to the static and dynamic quenching. Further, from the studies of temperature dependence of rate parameters and lifetime measurements, it could be explained that the positive deviation is due to the presence of a small static quenching component in the overall dynamic quenching. With the use of finite sink approximation model, it was possible to check whether these bimolecular reactions as diffusion limited and to estimate independently distance parameter R' and mutual diffusion coefficient D. Finally an effort has been made to correlate the values of R' and D with the values of the encounter distance R and the mutual diffusion coefficient D determined using the Edward's empirical relation and Stokes-Einstein relation.

  5. (1E,2E-N1,N2-Bis(5′-methyl-[1,1′:3′,1′′-terphenyl]-4′-ylacenaphthylene-1,2-diimine unknown solvent

    Directory of Open Access Journals (Sweden)

    Liqiong Zhu

    2016-04-01

    Full Text Available The title compound, C50H36N2, synthesized by the condensation reaction of 2-methyl-4,6-diphenylaniline and acenaphthylene-1,2-dione, crystallizes with two independent molecules (A and B in the asymmetric unit. The two molecules differ essentially in the orientation of the phenyl ring at position 3′ of the terphenyl group with respect to the central ring of this unit. In molecule A this dihedral angle is 16.68 (14°, while in molecule B the corresponding angle is 33.10 (16°. The three-fused-ring 1,2-dihydroacenaphthylene units are planar in each molecule; r.m.s. deviation of 0.025 Å in molecule A and 0.017 Å in molecule B. The central rings of the terphenyl groups are almost normal to the mean plane of the three-fused-ring units with dihedral angles of 79.43 (12 and 82.66 (13° in molecule A and 88.99 (13 and 87.98 (12° in molecule B. In the crystal, the two molecules are linked via a C—H...N hydrogen bond. These A–B units are linked by a pair of C—H...π interactions, forming a four-molecule unit located about an inversion center. These four-molecule units are linked by weak π–π interactions [most significant intercentroid distance = 3.794 (2 Å], forming columns along direction [010]. A region of disordered electron density was corrected for using the SQUEEZE routine in PLATON [Spek (2015. Acta Cryst. C71, 9–18]. The formula mass and unit-cell characteristics of this unknown solvent were not be taken into account during the refinement.

  6. Structure of organic and metal-organic networks based on a bifunctional m-terphenyl carboxylic acid.

    Science.gov (United States)

    Dickie, Diane A; Schatte, Gabriele; Jennings, Michael C; Jenkins, Hilary A; Khoo, Sarah Y L; Clyburne, Jason A C

    2006-02-20

    A series of metal-organic frameworks (MOFs) based upon the ligand 2,6-diphenyl-1,4-dibenzoic acid [Ph2C6H2(CO2H)2]infinity have been prepared and characterized by X-ray crystallography. The networks exhibit a variety of topologies and coordination modes at the metal center. The reaction of the ligand with cobalt(II) nitrate or zinc(II) nitrate in methanol/pyridine results in the formation of isostructural 1-D chains [(Ph2C6H2(CO2)2)M(py)2(MeOH)]infinity, where M = Zn, Co; however, in the presence of ethanol and triethylamine, Zn(NO3)2 reacts to form a 2-D clay-like network, [(Ph2C6H2(CO2)2)Zn(EtOH)2]infinity. 2-D networks are also formed in similar reactions with copper(II) nitrate or silver(I) nitrate to give [(Ph2C6H2(CO2)(CO2H))2Cu(py)2]infinity, [(Ph2C6H2(CO2)CO2H))2Cu(py)4.2H2O](infinity), and [(Ph2C6H2(CO2)2)Ag2]infinity, respectively. The hydrogen-bonded chains formed by the ligand alone and with 4,4'-dipyridyl are also described.

  7. Studies on Pd/NiFe2O4 catalyzed ligand-free Suzuki reaction in aqueous phase: synthesis of biaryls, terphenyls and polyaryls

    Directory of Open Access Journals (Sweden)

    Suresh B. Waghmode

    2011-03-01

    Full Text Available Palladium supported on nickel ferrite (Pd/NiF2O4 was found to be a highly active catalyst for the Suzuki coupling reaction between various aryl halides and arylboronic acids. The reaction gave excellent yields (70–98% under ligand free conditions in a 1:1 DMF/H2O solvent mixture, in short reaction times (10–60 min. The catalyst could be recovered easily by applying an external magnetic field. The polyaryls were similarly synthesized.

  8. CCDC 1420585: Experimental Crystal Structure Determination : catena-[(mu-22,25-bis(4-carboxyphenyl)[11,21:24,31-terphenyl]-14,34-dicarboxylato)-calcium ethane

    KAUST Repository

    Plonka, Anna M.

    2016-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  9. CCDC 1420584: Experimental Crystal Structure Determination : catena-[(mu-22,25-bis(4-carboxyphenyl)[11,21:24,31-terphenyl]-14,34-dicarboxylato)-calcium ethylene

    KAUST Repository

    Plonka, Anna M.

    2016-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  10. CCDC 1420583: Experimental Crystal Structure Determination : catena-[(mu-22,25-bis(4-carboxyphenyl)[11,21:24,31-terphenyl]-14,34-dicarboxylato)-calcium acetylene

    KAUST Repository

    Plonka, Anna M.

    2016-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  11. SYNTHESIS AND MUTAGENICITY OF DIRECT DYES FROM 4,4'-DIAMINO-PARA-TERPHENYL AND 4,4'-DIAMINO-PARA-QUATERPHENYL

    Science.gov (United States)

    DBPs in drinking water can be controlled by the type of treatment and by knowing and controlling major sources of DBP toxicant precursors and toxicants that "evade" treatment processes. Efforts are being directed at one category at a time. The initial precursor categories to be c...

  12. Crystal structure of [1,1′:3′,1′′-terphenyl]-2′,3,3′′-tricarboxylic acid

    Directory of Open Access Journals (Sweden)

    Daniel A. Decato

    2015-09-01

    Full Text Available The asymmetric unit of the title compound, C21H14O6, comprises two symmetrically independent molecules that form a locally centrosymmetric hydrogen-bonded dimer, with the planes of the corresponding carboxylic acid groups rotated by 15.8 (1 and 17.5 (1° relative to those of the adjacent benzene rings. The crystal as a whole, however, exhibits a noncentrosymmetric packing, described by the polar space group Pca21. The dimers form layers along the ab plane, being interconnected by hydrogen bonds involving the remaining carboxylic acid groups. The plane of the central carboxylic acid group forms dihedral angles of 62.5 (1 and 63.0 (1° with those of the adjacent benzene rings and functions as a hydrogen-bond donor and acceptor. As a donor, it interconnects adjacent layers, while as an acceptor it stabilizes the packing within the layers. The `distal' carboxylic acid groups are nearly coplanar with the planes of the adjacent benzene rings, forming dihedral angles of 1.8 (1 and 7.1 (1°. These groups also form intra- and inter-layer hydrogen bonds, but with `reversed' functionality, as compared with the central carboxylic acid groups.

  13. (E-1-(4,4′′-Difluoro-5′-methoxy-1,1′:3′,1′′-terphenyl-4′-yl-3-(6-methoxynaphthalen-2-ylprop-2-en-1-one

    Directory of Open Access Journals (Sweden)

    Hoong-Kun Fun

    2011-12-01

    Full Text Available In the title compound, C33H24F2O3, the central benzene ring makes dihedral angles of 44.71 (10, 47.80 (10 and 63.68 (9° with the two fluoro-substituted benzene rings and the naphthalene ring system, respectively. In the crystal, molecules are connected via intermolecular C—H...F and C—H...O hydrogen bonds. Furthermore, the crystal structure is stabilized by weak C—H...π and π–π interactions [centroid–centroid distance = 3.6816 (13 Å].

  14. CCDC 866715: Experimental Crystal Structure Determination : catena-((mu~12~-tris(4-(5'-ethynyl-1,1':3''.1''-terphenyl-4,4''-dicarboxylic acid)phenyl)amine)-tri-aqua-tri-copper unknown solvate)

    KAUST Repository

    Eubank, J.F.

    2013-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  15. CCDC 1050064: Experimental Crystal Structure Determination : catena-[tetrakis(dimethylammonium) hexadecakis(mu-oxo)-hexakis(mu-3,3'',5,5''-tetrakis[2-(4-carboxylatophenyl)ethynyl]-p-terphenyl)-dodeca-yttrium unknown solvate

    KAUST Repository

    Luebke, Ryan

    2015-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  16. Development and validation of methods for the analysis of polychlorinated biphenyls and polychlorinated terphenyls in organic materials; Erarbeitung und Validierung von Verfahren zur Bestimmung von polychlorierten Biphenylen und polychlorierten Terphenylen in organischen Materialien

    Energy Technology Data Exchange (ETDEWEB)

    Lehnik-Habrink, Petra; Schuetz, Sebastian; Redlich, Christel; Win, Tin; Philipp, Rosemarie; Kaminski, Katja [Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin (Germany)

    2005-04-15

    The aim of the project was to develop and validate a testing method for the determination of PCB and PCT in organic waste matrices such as cable covering material, waste wood and automotive shredder residue. The proposed method contains steps to grind the sample, extraction, clean up and quantification. For each matrix a maximum particle sizes was determined, necessary for reproducible results. A test series with different extraction methods such as accelerated solvent extraction (ASE), sonication extraction, shaking extraction and Soxhlet extraction was carried out to compare various extraction techniques. Solvent and extraction times were varied. Different clean up methods were tested and evaluated. The results were taken into account in the method proposal. For quantification the GC/ECD procedure is favored, since hereby both PCB and PCB substitutes can be analysed simultaneously within one chromatographic run, if the detector response is sufficient. In presence of interfering substances like polychlorinated naphthalenes PCB can be quantified by variation of the GC-conditions. For the quantitation of PCT a calculation method based on freely selectable congeners is suggested. For the investigation of PCB and PCT in waste quality-assurance measures are formulated, which correspond both with the legal as well as the analytic requirements. (orig.)

  17. CCDC 1432977: Experimental Crystal Structure Determination : catena-[tris(mu-5',5''-naphthalene-1,4-diylbis(1,1':3',1''-terphenyl-4,4''-dicarboxylato))-bis(mu-oxo)-hexaaqua-hexa-aluminium dichloride

    KAUST Repository

    Alezi, Dalal

    2015-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  18. CCDC 1050063: Experimental Crystal Structure Determination : catena-[tetrakis(dimethylammonium) hexadecakis(mu-oxo)-hexakis(mu-3,3'',5,5''-tetrakis(4-carboxylatophenyl)-p-terphenyl)-dodecaaqua-dodeca-yttrium unknown solvate

    KAUST Repository

    Luebke, Ryan

    2015-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  19. CCDC 1432978: Experimental Crystal Structure Determination : catena-[tris(mu-1,4-bis(4,4''-dicarboxylato-1,1':3',1''-terphenyl-5'-yl)benzene)-bis(mu-oxo)-hexaaqua-hexa-aluminium dichloride

    KAUST Repository

    Alezi, Dalal

    2015-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  20. Ethyl ({5-[5′-(2-ethoxy-2-oxoethoxy-4,4′′-difluoro-1,1′:3′,1′′-terphenyl-4′-yl]-1,3,4-oxadiazol-2-yl}sulfanylacetate

    Directory of Open Access Journals (Sweden)

    B. K. Sarojini

    2012-03-01

    Full Text Available In the title compound, C28H24F2N2O6S, the whole molecule is disordered over two sites with refined occupancies of 0.778 (3 and 0.222 (3. The central benzene ring makes dihedral angles of 56.0 (4, 34.5 (4 and 70.9 (4°, respectively, with the two terminal benzene rings and the 1,3,4-oxadiazole ring in the major component of the disordered molecule. The corresponding angles in the minor component are 59.7 (16, 25.6 (13 and 75.5 (14°. In the crystal, molecules are linked via C—H...F, C—H...N, C—H...O and C—H...S hydrogen bonds into a three-dimensional network. In addition, C—H...π interactions are observed.

  1. Ultrasensitive Laser Spectroscopy in Solids: Statistical Fine Structure and Single-Molecule Detection

    Science.gov (United States)

    1990-03-28

    the measurement. Keywords: Statistical fine structure, Atomic properties, Single molecule detection, Molecule properties, Laser spectroscopy of solids, Instrumentation, Pentacene in p-terphenyl, Organic compounds, Near field.

  2. Synthesis and photophysics of light-converting lanthanide complexes

    NARCIS (Netherlands)

    Klink, S.I.

    2000-01-01

    The work described in this thesis deals with the synthesis, characterization, and photophysical studies of luminescent lanthanide complexes that are based on m-terphenyl and calix[4]arene building blocks.

  3. Triplet State Resonance Raman Spectroscopy

    DEFF Research Database (Denmark)

    Wilbrandt, Robert Walter; Jensen, N. H.; Pagsberg, Palle Bjørn

    1978-01-01

    Makes the first report on the resonance Raman spectrum of a molecule in its triplet state generated by pulse radiolysis. A solution of 0.01 mol dm-3 of p-terphenyl in benzene was studied......Makes the first report on the resonance Raman spectrum of a molecule in its triplet state generated by pulse radiolysis. A solution of 0.01 mol dm-3 of p-terphenyl in benzene was studied...

  4. CCDC 953497: Experimental Crystal Structure Determination : catena-[bis(mu-9-[4-((3,5-bis[(4,4''-dicarboxylato-1,1':3',1''-terphenyl-5'-yl)ethynyl]phenyl)ethynyl)phenyl]-9H-carbazole-3,6-dicarboxylato)-hexa-aqua-hexa-copper(ii) unknown solvate

    KAUST Repository

    Guillerm, Vincent

    2014-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  5. CCDC 866709: Experimental Crystal Structure Determination : catena-(dodecakis(mu~6~-5'-(1H-tetrazol-5-yl)-1,1':3',1''-terphenyl-4,4''-dicarboxylato)-tetrakis(mu~3~-oxo)-hexatriaconta-aqua-tetracosa-copper nitrate monohydrate)

    KAUST Repository

    Eubank, J.F.

    2013-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  6. N-(1,3-Dioxo-2,3-dihydro-1H-isoindol-2-yl-4,4′′-difluoro-5′-hydroxy-1,1′:3′,1′′-terphenyl-4′-carboxamide

    Directory of Open Access Journals (Sweden)

    Hoong-Kun Fun

    2012-09-01

    Full Text Available The asymmetric unit of the title compound, C27H16F2N2O4, consists of two crystallographically independent molecules (A and B. In molecule B, the isoindoline-1,3-dione ring system is disordered over two set of sites with a site-occupancy ratio of 0.658 (12:0.342 (12. In molecule A, the fluoro-substituted benzene rings make dihedral angles of 18.36 (8 and 46.37 (8° with the central benzene ring, whereas the corresponding angles are 40.90 (8 and 52.89 (9° in molecule B. The isoindoline ring system in molecule A and the major and minor components of the disordered isoindoline ring system in molecule B make dihedral angles of 58.50 (4, 54.13 (16 and 70.01 (28 °, respectively, with their attached benzene rings, linked through the amide group. An intramolecular O—H...O hydrogen bond generates an S(6 ring in each molecule. In the crystal, molecules are linked by N—H...O, C—H...F and C—H...O hydrogen bonds into sheets lying parallel to the bc plane. The crystal studied was a non-merohedral twin with a refined twin component ratio of 0.9316 (8:0.0684 (8.

  7. 5-(4,4′′-Difluoro-5′-hydroxy-1,1′:3′,1′′-terphenyl-4′-yl-3-(morpholin-4-ylmethyl-1,3,4-oxadiazole-2(3H-thione

    Directory of Open Access Journals (Sweden)

    Hoong-Kun Fun

    2011-12-01

    Full Text Available In the title compound, C25H21F2N3O3S, the morpholine ring adopts a chair conformation. The 1,3,4-oxadiazole-2(3H-thione group makes dihedral angles of 78.69 (8, 53.56 (7 and 55.30 (9° with the benzene rings. In the crystal, O—H...O, C—H...S and C—H...F hydrogen bonds linked the molecules into layers lying parallel to the ab plane. Weak C—H...π interactions also occur.

  8. Design and modular parallel synthesis of a MCR derived α-helix mimetic protein-protein interaction inhibitor scaffold

    NARCIS (Netherlands)

    Antuch, Walfrido; Menon, Sanjay; Chen, Quin-Zene; Lu, Yingchun; Sakamuri, Sukumar; Beck, Barbara; Schauer-Vukašinović, Vesna; Agarwal, Seema; Hess, Sibylle; Dömling, Alexander

    2006-01-01

    A terphenyl α-helix mimetic scaffold recognized to be capable of disrupting protein-protein interactions was structurally morphed into an easily amenable and versatile multicomponent reaction (MCR) backbone. The design, modular in-parallel library synthesis, initial cell based biological data, and

  9. Fast Resonance Raman Spectroscopy of Short-Lived Radicals

    DEFF Research Database (Denmark)

    Pagsberg, Palle Bjørn; Wilbrandt, Robert Walter; Hansen, Karina Benthin

    1976-01-01

    We report the first application of pulsed resonance Raman spectroscopy to the study of short-lived free radicals produced by pulse radiolysis. A single pulse from a flash-lamp pumped tunable dye laser is used to excite the resonance Raman spectrum of the p-terphenyl anion radical with an initial...

  10. a -1-2-1

    African Journals Online (AJOL)

    branes' should be replaced by 'prelabour rupture of the membranes', either preterm or at term. Despite these comments, Midwifery is an impressive achievement and the books are thoroughtly recommended. H. A. VAN COEVERDEN DE GROOT. Books received November 1993. Polycblorinated Biphenyls and Terphenyls.

  11. Single-molecule fluorescence autocorrelation experiments on pentacene : The dependence of intersystem crossing on isotopic composition

    NARCIS (Netherlands)

    Brouwer, A.C.J.; Köhler, J.; Oijen, A.M. van; Groenen, E.J.J.; Schmidt, J.

    1999-01-01

    Single pentacene molecules containing 13C or 1H in a pentacene-d14 doped p-terphenyl crystal have been studied by fluorescence autocorrelation. The triplet dynamics has been analyzed and a systematic dependence of the S1→T1 intersystem crossing rate on isotopic composition was found. This variation

  12. Bottom-up fabrication of graphene on Ru(0001) via molecular self-assembly

    Science.gov (United States)

    Cai, Yiliang; Zhang, Hanjie; Song, Junjie; Zhang, Yuxi; Rehman, A. U.; He, Pimo

    2015-07-01

    A bottom-up fabrication of graphene via molecular self-assembly of p-Terphenyl on Ru(0001) has been investigated by scanning tunneling microcopy and density functional theory. Upon annealing of the sample at 450 °C, the intermediate stage is observed, in which the adsorbed p-Terphenyl molecules and graphitized flakes converted from the molecules coexist, implying the onset of dehydrogenation of p-Terphenyl. At the annealing temperature of 480 °C, the graphitized flakes start to convert into graphene. An adsoption energy of 5.99 eV is calculated for an individual p-Terphenyl molecule on Ru(0001), denoting a strong interaction between the adsorbate and substrate. The intermolecular interaction brings an extra adsorption energy of 0.28 eV for each molecule in the di-molecule adsorption system. During the conversion process from adsorbed molecule into graphene, the intermolecular interaction leads to the increase of the dehydrogenation barrier from 1.52 to 1.64 eV.

  13. Crystallization dynamics in glass-forming systems

    Energy Technology Data Exchange (ETDEWEB)

    Cullinan, Timothy Edward [Iowa State Univ., Ames, IA (United States)

    2016-02-19

    Crystallization under far-from-equilibrium conditions is investigated for two different scenarios: crystallization of the metallic glass alloy Cu50Zr50 and solidification of a transparent organic compound, o-terphenyl. For Cu50Zr50, crystallization kinetics are quanti ed through a new procedure that directly fits thermal analysis data to the commonly utilized JMAK model. The phase evolution during crystallization is quantified through in-situ measurements (HEXRD, DSC) and ex-situ microstructural analysis (TEM, HRTEM). The influence of chemical partitioning, diffusion, and crystallographic orientation on this sequence are examined. For o-terphenyl, the relationship between crystal growth velocity and interface undercooling is systematically studied via directional solidification.

  14. CMS Hadronic EndCap Calorimeter Upgrade R&D Studies

    CERN Document Server

    Akgun, Ugur; Onel, Yasar

    2012-01-01

    Due to an expected increase in radiation damage in LHC, we propose to replace the active material of the CMS Hadronic EndCap calorimeters with radiation hard quartz plate. Quartz is proven to be radiation hard with radiation damage tests using electron, proton, neutron and gamma beams. However, the light produced in quartz is from Cerenkov process, which yields drastically fewer photons than scintillators. To increase the light collection efficiency we pursue two separate methods: First method: use wavelength shifting (WLS) fibers, which have been shown to collect efficiently the Cerenkov light generated in quartz plates. A quartz plate calorimeter prototype with WLS fibers has been constructed and tested at CERN that shows this method is feasible. Second proposed solution is to treat the quartz plates with radiation hard wavelength shifters, p-terphenyl, doped zinc oxide, or doped CdS. Another calorimeter prototype has been constructed with p-terphenyl deposited quartz plates, and showed superior calorimeter...

  15. Single Molecule Spectral Diffusion in a Solid Detected Via Fluorescence Spectroscopy

    Science.gov (United States)

    1991-10-15

    NO. NO ACCESSION NO. 11. TITLE (Include Security Classification) Single Molecule Spectral Diffusion In A Solid Detected Via Fluorescence Spectroscopy...and identify by block number) FIELD jGROUP SUB-GROUP_ Single molecule spectroscopy Precision detection Spectral diffusion, Pentacene in p-terphenyl 19... Single Molecule Spectral Diffusion ’n A Solid Detected Via Fluorescence Spectroscopy hy W. P. Ambrose, T. Basche, and W. E. Moerner

  16. Energy Storage As Heat-of-Fusion in Containerized Salts.

    Science.gov (United States)

    1980-06-27

    las mezclas terfenili- cas comerciales,* J.E.N. 123 DQ/137. (Junta de Energia Nuclear, Ciudad Universitaria , Madrid , Spain) F2. Rhone-Poulenc...evaluated quantitatively at NRL, but has been studied de Halas, working with separated terphenyls and by Pinero and Rodriguez working with Gilotherm...that no trouble should be encountered in the proof-of-concept demonstration over several months. Lifetime estimates based on de Halas data and on

  17. Time resolved multiphoton excited fluorescence probes in model membranes

    CERN Document Server

    Bai, Y

    2000-01-01

    Using the time-correlated single-photon counting technique, this thesis reports on a time-resolved fluorescence study of several fluorescent probes successfully employed in membrane research. Concentration and temperature effects on fluorescence anisotropy parameters are demonstrated by DPH, p-terphenyl, alpha-NPO and PPO in DPPC lipid bilayers. Fluorescence anisotropy has shown that trans-stilbene and Rhd 800 have a two-site location in membranes. Multiphoton induced fluorescence of DPH, p-terphenyl, alpha-NPO and v-biphenyl in liposomes was measured using 800nm excitation with a femtosecond Ti:Sapphire laser. P-terphenyl, alpha-NPO and v-biphenyl are new probes for membranes. Comparison of one and multiphoton excitation results has demonstrated higher initial anisotropy with multiphoton excitation than with one-photon excitation. The rotational times were identical for one and multiphoton excitation, indicating the absence of significant local heating or sample perturbation. Excimer formation of alpha-NPO w...

  18. Reassembling and testing of a high-precision heat capacity drop calorimeter. Heat capacity of some polyphenyls at T = 298.15 K

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Luis M.N.B.F., E-mail: lbsantos@fc.up.pt [Centro de Investigacao em Quimica, Departamento de Quimica e Bioquimica, Faculdade de Ciencias, Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto (Portugal); Rocha, Marisa A.A.; Rodrigues, Ana S.M.C. [Centro de Investigacao em Quimica, Departamento de Quimica e Bioquimica, Faculdade de Ciencias, Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto (Portugal); Stejfa, Vojtech; Fulem, Michal [Department of Physical Chemistry, Institute of Chemical Technology, Technicka 5, CZ-166 28 Prague 6 (Czech Republic); Bastos, Margarida [Centro de Investigacao em Quimica, Departamento de Quimica e Bioquimica, Faculdade de Ciencias, Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto (Portugal)

    2011-12-15

    Graphical abstract: Highlights: > We present the reassembling, improvement and testing of a high-precision C{sub p} drop calorimeter. > The apparatus was tested, using benzoic acid and hexafluorobenzene. > The high sensitivity of the apparatus is comparable to the one obtained in adiabatic calorimetry. > Heat capacities at T = 298.15 K of some polyphenyls were measured. > Subtle heat capacity differences among position isomers (ortho, meta, para) were detected. - Abstract: The description of the reassembling and testing of a twin heat conduction, high-precision, drop microcalorimeter for the measurement of heat capacities of small samples are presented. The apparatus, originally developed and used at the Thermochemistry Laboratory, Lund, Sweden, has now been reassembled and modernized, with changes being made as regarding temperature sensors, electronics and data acquisition system. The apparatus was thereafter thoroughly tested, using benzoic acid and hexafluorobenzene as test substances. The accuracy of the C{sub p,m}{sup 0} (298.15 K) data obtained with this apparatus is comparable to that achieved by high-precision adiabatic calorimetry. Here we also present the results of heat capacity measurements on of some polyphenyls (1,2,3-triphenylbenzene, 1,3,5-triphenylbenzene, p-terphenyl, m-terphenyl, o-terphenyl, p-quaterphenyl) at T = 298.15 K, measured with the renewed high precision heat capacity drop calorimeter system. The high resolution and accuracy of the obtained heat capacity data enabled differentiation among the ortho-, meta-, and para-phenyl isomers.

  19. Change of translational-rotational coupling in liquids revealed by field-cycling 1H NMR.

    Science.gov (United States)

    Meier, R; Schneider, E; Rössler, E A

    2015-01-21

    Applying the field-cycling nuclear magnetic resonance technique, the frequency dependence of the (1)H spin-lattice relaxation rate, R1ω=T1(-1)ω, is measured for propylene glycol (PG) which is increasingly diluted with deuterated chloroform. A frequency range of 10 kHz-20 MHz and a broad temperature interval from 220 to about 100 K are covered. The results are compared to those of experiments, where glycerol and o-terphenyl are diluted with their deuterated counter-part. Reflecting intra- as well as intermolecular relaxation, the dispersion curves R1ω,x (x denotes mole fraction PG) allow to extract the rotational time constant τrot(T, x) and the self-diffusion coefficient D(T, x) in a single experiment. The Stokes-Einstein-Debye (SED) relation is tested in terms of the quantity D(T, x) τrot(T, x) which provides a measure of an effective hydrodynamic radius or equivalently of the spectral separation of the translational and the rotational relaxation contribution. In contrast to o-terphenyl, glycerol and PG show a spectral separation much larger than suggested by the SED relation. In the case of PG/chloroform mixtures, not only an acceleration of the PG dynamics is observed with increasing dilution but also the spectral separation of rotational and translational relaxation contributions continuously decreases. Finally, following a behavior similar to that of o-terphenyl already at about x = 0.6; i.e., while D(T, x) τrot(T, x) in the mixture is essentially temperature independent, it strongly increases with x signaling thus a change of translational-rotational coupling. This directly reflects the dissolution of the hydrogen-bond network and thus a change of solution structure.

  20. Substituent effect on color tuning of red light emission in photoluminescence and electroluminescence of red fluorophore.

    Science.gov (United States)

    Ryu, Gweon Young; Lee, Sang Gu; Shin, Sung Eui; Park, Jong Jin; Park, Seungho; Shin, Dong Myung

    2010-10-01

    Typical small red light-emitting molecules for organic light emitting diodes (OLEDs) were highly susceptible to fluorescence concentration quenching in solid state. Red fluorophores, (2Z, 2'Z)-3, 3'-[4,4"-bis(dimethylamino)-1,1':4',1"-terphenyl-29',5'-diyl]bis(2-phenylacrylonitrile) (ABCV-P), (2E, 2'E)-3,3'-[4,4"-bis(dimethylamino)-1,1':4',1"-terphenyl-2',5'-diyl]bis[2-(2-thienyl)acrylonitrile] (ABCV-Th) and (2Z, 2'Z)-3,3'-[4,4"-bis(dimethylamino)-1,1':4',1"-terphenyl-2',5'-diyl]bis[2-(2-naphthyl)acrylonitrile] (ABCV-Np), capable of preventing fluorescence concentration quenching were designed and synthesized. These compounds have intramolecular charge transfer (ICT) properties which were estimated by measurement of UV-Visible absorption and photoluminescence (PL) emission spectra with variation of solvent polarity (n-Hexane/Chloroform = 99/1, 1/1; Chloroform; Methylene chloride). The magnitude of ICT for ABCV-Th was measured to be the largest and that for ABCV-Np was slightly larger compared to that for ABCV-P. The magnitude of ICT resulted in a shift of peak wavelength of PL emission. Therefore, this result well supported substituent effect on the color change of PL emission. The peak wavelengths of photoluminescence for ABCV-P, ABCV-Np and ABCV-Th were observed to be 607.5, 611.5 and 617.5 nm, respectively, and those of EL spectra were measured to be 612.5, 619.5, 621.0 nm, respectively. The emission maxima of PL and EL spectra for these red fluorescent compounds were well correlated with substituent effect on ICT for them.

  1. Structure-Stability Relationships of Polymers Based on Thermogravimetric Analysis Data. Part 1. Polyaliphatics, Polyalicyclics, Spiro Polymers and Phenylene-R-Polymers

    Science.gov (United States)

    1974-12-01

    34copolymerized with m-terphenyl, naphthalene , biphenyl (cationic oxid. pol.) 340-460 370-590 Phenylated polyphenylenes )(.(J m 530-590 510-560 (C6H 5...more O residue at 9000C), unsubstituted, methyl- "- 370 or methoxy substituted rings and the 3C O0 replacement of phenylene by naphthalene or C-Ma-CHi...the diimide moieties:or % Sroog and coworkers (Ref. 35) compared polyimides of this type 0 0 OI?- 0 0 in helium. Tdec’s derived from their data show

  2. Systematic design and research on a series of cadmium coordination polymers assembled due to tetracarboxylate ligands

    Science.gov (United States)

    Lü, Lei; Mu, Bao; Li, Chang-Xia; Huang, Ru-Dan

    2016-02-01

    A series of metal-organic frameworks (MOFs) have been prepared by tetracarboxylate ligands and Cd(II) ions under the hydrothermal or solvothermal conditions with the formulas of {[Cd2(L1)(H2O)4]·H2O}n (1), {[(CH3)2NH2]2[Cd(L1)]}n (2), [Cd(L2)0.5(H2O)]n (3), {[(CH3)2NH2]2 [Cd(L2)]·2DMF}n (4), [Cd(L3)0.5(H2O)]n (5), {[Cd(L3)0.5(H2O)]·CH3OH}n (6), {[(CH3)2NH2]2[Cd3(L4)2]}n (7) (H4L1=[1,1‧:4‧,1″-terphenyl]-2,2″,5,5″-tetracarboxylic acid; H4L2=[1,1‧:4‧,1″-terphenyl]-2‧,4,4″,5‧-tetracarboxylic acid; H4L3=[1,1‧:3‧,1″-terphenyl]-2‧,3,3″,5‧-tetracarboxylic acid; H4L4=[1,1‧:4‧,1″-terphenyl]-3,3″,5,5″-tetracarboxylic acid), which are characterized by single-crystal X-ray diffraction, elemental analyses, IR, TGA and PXRD. Complex 1 exhibits a three-dimensional (3D) supramolecular framework based on two-dimensional (2D) coordination networks. Complexes 2 and 4 possess 3D framework based on the 1D right-handed helix channels. Complexes 3 and 7 are a 3D architecture containing two different channels. Isostructural complexes 5 and 6 display 3D framework. The different synthetic methods and coordination modes of the tetracarboxylates ligands have effect on formation of various MOFs. Moreover, the luminescent properties and N2 adsorption behaviors have been reported.

  3. Generation of UV radiation by vapors of complex molecules

    Energy Technology Data Exchange (ETDEWEB)

    Barkova, L.A.; Gruzinskii, V.V.; Danilova, V.I.; Degtiarenko, K.M.; Kopylova, T.N.; Kuznetsov, A.L.

    1981-08-01

    Laser action has been obtained in the following organic compounds under pumping by XeCl excimer laser radiation at 308 nm: para-terphenyl, 2-phenylbenzoxazole, 2-(n-tolyl)-benzoxaxole, 2-(n-methoxyphenyl)-benzoxazole, 2-(n-dimethylaminophenyl)-benzoxazole, 2-biphenylbenzoxazole, (2-alpha-naphthyl)-benzoxazole, 1.4-di(n-phenylethynyl)-benzole, and paraquaterphenyl. The nontuning lasing bands covered the range of 330-370 nm, and the most short-wavelength maximum (333.5 nm) was found for 2(n-methoxyphenyl)-benzoxazole. The lasing capability of the molecules was analyzed.

  4. Stimulated emission of ultraviolet radiation by vapors of complex molecules

    Energy Technology Data Exchange (ETDEWEB)

    Barkova, L.A.; Gruzinskii, V.V.; Danilova, V.I.; Degtyarenko, K.M.; Kopylova, T.N.; Kuznetsov, A.L.

    1981-08-01

    Lasing was observed in vapors of new organic compounds: para-terphenyl, 2-phenylbenzoxazole, 2-(n-tolyl) benzoxazole, 2-(n-methoxyphenyl) benzoxazole, 2-(n-dimethylaminophenyl) benzoxazole, 2-biphenylbenzoxazole, 2-(..cap alpha..-naphthyl) benzoxazole, and also 1,4-di(n-phenylethynyl) benzole, and para-quaterphenyl pumped transversely by XeCl excimer laser radiation at lambda/sub p/ = 308 nm. The lasing bands without tuning covered the 330--370 nm range. The shortest-wavelength maximum (333.5 nm) was observed for 2-(n-methoxyphenyl) benzoxazole. An analysis was made of the lasing ability of the molecules.

  5. A method for measuring the formation times of light flashes in scintillator films

    CERN Document Server

    Astvatsaturov, R G; Harutunyan, V N; Eganov, V S

    1999-01-01

    A method is proposed to estimate experimentally the formation times of light flashes in different types of scintillators. For illustration of the method a series of measurements with three following types of polystyrene (PS)-based scintillator films has been conducted: PS+1% 4'-vinyl-3-hydroxyflavone (4V3HF); PS+2% para-terphenyl (PTP)+0.007%4, 4'-distyrylbiphenyl( DSBP); PS+1% hydroxyflavone (3HF). The values obtained for the delays of light flashes were respectively: (0.2+-0.14) ns, (0.6+-0.17) ns and (0.9+-0.18) ns.

  6. Synthesis and Fluorescence Properties of 5,7-Diphenylquinoline and 2,5,7-Triphenylquinoline Derived from m-Terphenylamine

    Directory of Open Access Journals (Sweden)

    Hong Wang

    2007-05-01

    Full Text Available Synthesis of 5,7-phenylquinoline from the Skraup reaction of m-terphenyl-amine and glycerol in the presence of acid is reported. Further reaction of 5,7-diphenyl-quinoline with phenyl lithium prepared in situ led to the formation of 2,5,7-triphenyl-quinoline. All of the products and their intermediates were characterized and the UV-Vis and photo-luminescence (PL spectra of m-terphenylamine, 5,7-diphenylquinoline and 2,5,7-triphenylquinoline are also reported.

  7. Fibrous adsorbent for removal of aqueous aromatic hydrocarbons.

    Science.gov (United States)

    Jung, Yong-Jun; Kiso, Yoshiaki; Oguchi, Tatsuo; Yamada, Toshiro; Takagi, Hiroo; Nishimura, Kazuyuki

    2007-01-01

    Bundles of a strongly hydrophobic fibrous material (p-phenylene-2,6-benzobisoxazole; PBO; Zylon) were employed as an adsorbent for the removal of aqueous aromatic compounds, because the PBO fibers are too rigid to be woven and did not entrap suspended solids. The removal performance for nine kinds of polyaromatic hydrocarbons (PAHs) and di-(2-ethylhexyl) phthalate (DEHP) was evaluated. PAHs and DEHP at initial concentrations of 50 microg L(-1) were removed at 72.5-99.9% and ca. 95%, respectively, although the removal efficiencies were affected by the phase ratio (fiber weight/solution volume). The logarithm of the partition coefficient (log K) for planar PAHs was linearly correlated with the logarithm of the n-octanol/water partition coefficient (log P), but nonplanar PAHs, such as cis-stilbene, p-terphenyl, and o-terphenyl, showed significantly lower adsorption performance. The adsorbed PAHs were not desorbed effectively with CH3CN, CH2Cl2, and toluene. On the other hand, DEHP was effectively desorbed with methanol.

  8. Drastic reduction in the growth temperature of graphene on copper via enhanced London dispersion force.

    Science.gov (United States)

    Choi, Jin-Ho; Li, Zhancheng; Cui, Ping; Fan, Xiaodong; Zhang, Hui; Zeng, Changgan; Zhang, Zhenyu

    2013-01-01

    London dispersion force is ubiquitous in nature, and is increasingly recognized to be an important factor in a variety of surface processes. Here we demonstrate unambiguously the decisive role of London dispersion force in non-equilibrium growth of ordered nanostructures on metal substrates using aromatic source molecules. Our first-principles based multi-scale modeling shows that a drastic reduction in the growth temperature, from ~1000°C to ~300°C, can be achieved in graphene growth on Cu(111) when the typical carbon source of methane is replaced by benzene or p-Terphenyl. The London dispersion force enhances their adsorption energies by about (0.5-1.8) eV, thereby preventing their easy desorption, facilitating dehydrogenation, and promoting graphene growth at much lower temperatures. These quantitative predictions are validated in our experimental tests, showing convincing demonstration of monolayer graphene growth using the p-Terphenyl source. The general trends established are also more broadly applicable in molecular synthesis of surface-based nanostructures.

  9. Temperature dependence of the infinite dilution activity coefficient and Henry's law constant of polycyclic aromatic hydrocarbons in water.

    Science.gov (United States)

    Reza, Joel; Trejo, Arturo

    2004-08-01

    The water solubility of 9,10-dihydroanthracene was experimentally determined between 278.12 and 313.17 K. Determinations were carried out by an experimental procedure developed in our laboratory, which is a modification of the dynamic coupled column liquid chromatographic technique. The uncertainty of the experimental determinations ranged from +/- 0.50% to +/- 3.10%. These data, as well as the water solubility data of other five polycyclic aromatic hydrocarbons (PAHs) previously studied, were used to calculate the temperature dependence of the infinite dilution activity coefficient of 9,10-dihydroanthracene, anthracene, pyrene, 9,10-dihydrophenanthrene, m-terphenyl, and guaiazulene in water. Molar excess enthalpies and entropies at infinite dilution, at 298.15 K, were also derived. The temperature dependence of the infinite dilution activity coefficients was used, together with literature values of the vapor pressures of supercooled liquid PAHs (p(B)(sc)), to estimate their Henry's law constants (HLC). Only HLC for anthracene, pyrene, and 9,10-dihydrophenanthrene were calculated, since no p(B)(sc) data were available in the literature for 9,10-dihydroanthracene, m-terphenyl, and guaiazulene. From the observed temperature dependence of the Henry's law constants the enthalpy and entropy of the phase change from the dissolved phase to the gas phase were also derived for anthracene, pyrene, and 9,10-dihydrophenanthrene.

  10. Functionalized organic semiconductor molecules to enhance charge carrier injection in electroluminescent cell

    Science.gov (United States)

    Yalcin, Eyyup; Kara, Duygu Akin; Karakaya, Caner; Yigit, Mesude Zeliha; Havare, Ali Kemal; Can, Mustafa; Tozlu, Cem; Demic, Serafettin; Kus, Mahmut; Aboulouard, Abdelkhalk

    2017-07-01

    Organic semiconductor (OSC) materials as a charge carrier interface play an important role to improve the device performance of organic electroluminescent cells. In this study, 4,4″-bis(diphenyl amino)-1,1':3‧,1″-terphenyl-5'-carboxylic acid (TPA) and 4,4″-di-9H-carbazol-9-yl-1,1':3‧,1″-terphenyl-5'-carboxylic acid (CAR) has been designed and synthesized to modify indium tin oxide (ITO) layer as interface. Bare ITO and PEDOT:PSS coated on ITO was used as reference anode electrodes for comparison. Furthermore, PEDOT:PSS coated over CAR/ITO and TPA/ITO to observe stability of OSC molecules and to completely cover the ITO surface. Electrical, optical and surface characterizations were performed for each device. Almost all modified devices showed around 36% decrease at the turn on voltage with respect to bare ITO. The current density of bare ITO, ITO/CAR and ITO/TPA were measured as 288, 1525 and 1869 A/m2, respectively. By increasing current density, luminance of modified devices showed much better performance with respect to unmodified devices.

  11. Systematic design and research on a series of cadmium coordination polymers assembled due to tetracarboxylate ligands

    Energy Technology Data Exchange (ETDEWEB)

    Lü, Lei; Mu, Bao; Li, Chang-Xia; Huang, Ru-Dan, E-mail: huangrd@bit.edu.cn

    2016-02-15

    A series of metal-organic frameworks (MOFs) have been prepared by tetracarboxylate ligands and Cd(II) ions under the hydrothermal or solvothermal conditions with the formulas of {[Cd_2(L_1)(H_2O)_4]·H_2O}{sub n} (1), {[(CH_3)_2NH_2]_2[Cd(L_1)]}{sub n} (2), [Cd(L{sub 2}){sub 0.5}(H{sub 2}O)]{sub n} (3), {[(CH_3)_2NH_2]_2 [Cd(L_2)]·2DMF}{sub n} (4), [Cd(L{sub 3}){sub 0.5}(H{sub 2}O)]{sub n} (5), {[Cd(L_3)_0_._5(H_2O)]·CH_3OH}{sub n} (6), {[(CH_3)_2NH_2]_2[Cd_3(L_4)_2]}{sub n} (7) (H{sub 4}L{sub 1}=[1,1′:4′,1″-terphenyl]-2,2″,5,5″-tetracarboxylic acid; H{sub 4}L{sub 2}=[1,1′:4′,1″-terphenyl]-2′,4,4″,5′-tetracarboxylic acid; H{sub 4}L{sub 3}=[1,1′:3′,1″-terphenyl]-2′,3,3″,5′-tetracarboxylic acid; H{sub 4}L{sub 4}=[1,1′:4′,1″-terphenyl]-3,3″,5,5″-tetracarboxylic acid), which are characterized by single-crystal X-ray diffraction, elemental analyses, IR, TGA and PXRD. Complex 1 exhibits a three-dimensional (3D) supramolecular framework based on two-dimensional (2D) coordination networks. Complexes 2 and 4 possess 3D framework based on the 1D right-handed helix channels. Complexes 3 and 7 are a 3D architecture containing two different channels. Isostructural complexes 5 and 6 display 3D framework. The different synthetic methods and coordination modes of the tetracarboxylates ligands have effect on formation of various MOFs. Moreover, the luminescent properties and N{sub 2} adsorption behaviors have been reported. - Graphical abstract: A series of cadmium(II) high-dimensional coordination polymers constructed from four different kinds of tetracarboxylate ligands have been successfully prepared under hydrothermal or solvothermal conditions. The effect of solvents, the coordination modes of the tetracarboxylates and positions of carboxylate groups on the architectures of complexes 1–7 have been investigated in detail. The luminescent properties of the part of complexes, N{sub 2} adsorption behaviors of complexes 2, 4–7 have

  12. Using LEDs to stimulate the recovery of radiation damage to plastic scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Wetzel, J., E-mail: james-wetzel@uiowa.edu [The University of Iowa, Iowa City, IA (United States); Tiras, E. [The University of Iowa, Iowa City, IA (United States); Bilki, B. [The University of Iowa, Iowa City, IA (United States); Beykent University, Istanbul (Turkey); Onel, Y. [The University of Iowa, Iowa City, IA (United States); Winn, D. [Fairfield University, Fairfield, CT (United States)

    2017-03-15

    In this study, we consider using LEDs to stimulate the recovery of scintillators damaged from radiation in high radiation environments. We irradiated scintillating tiles of polyethylene naphthalate (PEN), Eljen brand EJ-260 (EJN), an overdoped EJ-260 (EJ2P), and a lab-produced elastomer scintillator (ES) composed of p-terphenyl (ptp) in epoxy. Two different high-dose irradiations took place, with PEN dosed to 100 kGy, and the others to 78 kGy. We found that the ‘blue’ scintillators (PEN and ES) recovered faster and maximally higher with LEDs than without. Conversely exposing the ‘green’ scintillators (EJ-260) to LED light had a nearly negligible effect on the recovery. We hypothesize that the ‘green’ scintillators require wavelengths that match their absorption and emission spectra for LED stimulated recovery.

  13. Synthesis and characterization of low-melting scintillating glass doped with organic activator

    CERN Document Server

    Zhao Hong Sheng; Zhu Dong Mei; Wu Jing

    2000-01-01

    New colliders for high-energy physics studies require scintillators with short decay time, high density, good radiation hardness and low cost. It is possible to make glass scintillators that can meet these requirements by doping organic scintillating activators into an inorganic glass host. In this research, p-Terphenyl as the activator is doped into lead-tin-fluorophosphate glasses. There is no detectable change of the dopant on the densities and characteristic temperatures of the glass host. The hybrid scintillating glasses doped with p-TP possess 5 ns decay time and a broad fluorescence emission band, the peak of which is at about 545 nm. Although the light yields of the glasses are low, this research shows that it is possible to develop good hybrid scintillating glasses by doping organic activators into inorganic glass host.

  14. Increased lateral dipole moment in the core region of potential ferroelectric liquid crystal molecules

    Science.gov (United States)

    Tiemann, Bruce G.

    2000-10-01

    Visual displays, unlike audio systems, fall far short of human limits: orders of magnitude in information content separate what can be seen from what can be displayed. One technology employed for next-generation high-performance displays uses ferroelectric liquid crystals (FLCs), whose switching speed depends in part on the ferroelectric polarization of the active material, which itself arises from the lateral dipole moment of the constituent molecules. Several series of molecules based on the 2,3-dinitrophenyl moiety, which has a high lateral dipole moment, was conceived and prepared. Most of the new molecules did not exhibit any liquid crystal phases, but those that did had high polarization as expected. One such molecule, 2,3-Dinitro-4-(R)-(2-octyloxy)phenyl 4'-decyloxy-4-biphenylcarboxylate, had a polarization density of over 500 nC/cm2. Compounds with other core geometries, including phenyls, phenyl benzoates, biphenyls, and terphenyls, were prepared but failed to exhibit liquid crystal phases.

  15. CMS Hadron Endcap Calorimeter Upgrade Studies for Super-LHC

    CERN Document Server

    Bilki, Burak

    2010-01-01

    When the Large Hadron Collider approaches Super-LHC conditions above a luminosity of $10^{34} cm^{-2} s^{-1}$, the scintillator tiles of the CMS Hadron Endcap calorimeters will lose their efficiencies. As a radiation hard solution, the scintillator tiles are planned to be replaced by quartz plates. In order to improve the efficiency of the photodetection, various methods were investigated including radiation hard wavelength shifters, p-terphenyl or 4\\% gallium doped zinc oxide. We constructed a 20 layer calorimeter prototype with pTp coated plates of size 20 cm x 20 cm, and tested the hadronic and the electromagnetic capabilities at the CERN H2 beam-line. The beam tests revealed a substantial light collection increase with pTp or ZnO:Ga deposited quartz plates. Here we report on the current R\\&D for a viable endcap calorimeter solution for CMS with beam tests and radiation damage studies.

  16. Energy Renormalization for Coarse-Graining the Dynamics of a Model Glass-Forming Liquid.

    Science.gov (United States)

    Xia, Wenjie; Song, Jake; Hansoge, Nitin K; Phelan, Frederick R; Keten, Sinan; Douglas, Jack F

    2018-02-15

    Coarse-grained modeling achieves the enhanced computational efficiency required to model glass-forming materials by integrating out "unessential" molecular degrees of freedom, but no effective temperature transferable coarse-graining method currently exists to capture dynamics. We address this fundamental problem through an energy-renormalization scheme, in conjunction with the localization model of relaxation relating the Debye-Waller factor ⟨u 2 ⟩ to the structural relaxation time τ. Taking ortho-terphenyl as a model small-molecule glass-forming liquid, we show that preserving ⟨u 2 ⟩ (at picosecond time scale) under coarse-graining by renormalizing the cohesive interaction strength allows for quantitative prediction of both short- and long-time dynamics covering the entire temperature range of glass formation. Our findings provide physical insights into the dynamics of cooled liquids and make progress for building temperature-transferable coarse-grained models that predict key properties of glass-forming materials.

  17. Chain-length-dependent intermolecular packing in polyphenylenes: a high pressure study

    CERN Document Server

    Heimel, G; Oehzelt, M; Hummer, K; Koppelhuber-Bitschnau, B; Porsch, F; Ambrosch-Draxl, C; Resel, R

    2003-01-01

    We report on pressure-induced structural changes in crystalline oligo(para-phenylenes) containing two to six phenyl rings. The results are discussed with particular emphasis put on the implications these changes in intermolecular distances and molecular arrangement have on important bulk properties of this class of materials, such as optical response and charge transport. We performed energy dispersive x-ray diffraction in a systematic study on polycrystalline powders of biphenyl, para-terphenyl, p-quaterphenyl, p-quinquephenyl and p-sexiphenyl under hydrostatic pressure up to 60 kbar. Revisiting the crystal structures at ambient conditions reveals details in the packing principle. A linear relationship between the density at ambient conditions and the number of phenyl rings is found. High pressure data not only yields pressure-dependent lattice parameters and hints towards pressure-induced changes in the molecular arrangement but also allows for an analysis of the equations of state of these substances as a ...

  18. Three-dimensional orientational colocalization of individual donor--acceptor pairs.

    Science.gov (United States)

    Hubner, Christian G; Ksenofontov, Vsevolod; Nolde, Fabian; Mullen, Klaus; Basche, Thomas

    2004-06-15

    We report on the determination of the three-dimensional orientation of the donor and acceptor transition dipoles in individual fluorescence resonance energy transfer (FRET) pairs by means of scanning optical microscopy with annular illumination. Knowledge of the mutual orientation of the donor and acceptor dipole is mandatory for reliable distance determination based on FRET efficiency measurements. In our model system perylenediimide as the donor and terryelenediimide as the acceptor are coupled via a stiff p-terphenyl linker. The absorption dipoles of the donor and acceptor are selectively addressed by the 488 nm and 647 line of an Ar/Kr mixed gas laser, respectively. A clear deviation from collinearity is observed with a distribution of misalignment angles peaked around 22 degrees.

  19. A novel metal-organic framework for high storage and separation of acetylene at room temperature

    Science.gov (United States)

    Duan, Xing; Wang, Huizhen; Ji, Zhenguo; Cui, Yuanjing; Yang, Yu; Qian, Guodong

    2016-09-01

    A novel 3D microporous metal-organic framework with NbO topology, [Cu2(L)(H2O)2]•(DMF)6·(H2O)2 (ZJU-10, ZJU = Zhejiang University; H4L =2‧-hydroxy-[1,1‧:4‧,1″-terphenyl]-3,3″,5,5″-tetracarboxylic acid; DMF =N,N-dimethylformamide), has been synthesized and structurally characterized. With suitable pore sizes and open Cu2+ sites, ZJU-10a exhibits high BET surface area of 2392 m2/g, as well as moderately high C2H2 volumetric uptake capacity of 132 cm3/cm3. Meanwhile, ZJU-10a is a promising porous material for separation of acetylene from methane and carbon dioxide gas mixtures at room temperature.

  20. Radiation Hard Active Media R&D for CMS Hadron Endcap Calorimetry

    Science.gov (United States)

    Tiras, Emrah; CMS-HCAL Collaboration

    2015-04-01

    The High Luminosity LHC era imposes unprecedented radiation conditions on the CMS detectors targeting a factor of 5-10 higher than the LHC design luminosity. The CMS detectors will need to be upgraded in order to withstand these conditions yet maintain/improve the physics measurement capabilities. One of the upgrade options is reconstructing the CMS Endcap Calorimeters with a shashlik design electromagnetic section and replacing active media of the hadronic section with radiation-hard scintillation materials. In this context, we have studied various radiation-hard materials such as Polyethylene Naphthalate (PEN), Polyethylene Terephthalate (PET), HEM and quartz plates coated with various organic materials such as p-Terphenyl (pTp), Gallium doped Zinc Oxide (ZnO:Ga) and Anthracene. Here we discuss the related test beam activities, laboratory measurements and recent developments.

  1. R and D on Radiation Hard Active Media Based on Quartz Plates

    CERN Document Server

    Onel, Yasar

    2014-01-01

    The need for radiation-hard active media in particle detectors is prominently dictated by the future colliders and the future operations of the Large Hadron Collider. The areas of implementation range from calorimetry to beamline instrumentation to specialized forward detectors e.g. luminosity monitors. In this context, we developed the idea of utilizing quartz plates with various surface coating properties as the active medium for such detectors. Plain quartz is a pure Cerenkov radiator which has quite limited photostatistics. In order to improve the efficiency of the photodetection, various methods were investigated including radiation hard wavelength shifters, p-terphenyl or 4pct gallium doped zinc oxide. The readout options include direct coupling of the photodetector to the quartz plate, or fibers. We have studied various geometries and readout options and constructed calorimeter prototypes. Here we report on the results of the previous tests, and the recent developments, which enable several factors of ...

  2. Radiation Hard and High Light Yield Scintillator Search for CMS Phase II Upgrade

    CERN Document Server

    Tiras, Emrah

    2015-01-01

    The CMS detector at the LHC requires a major upgrade to cope with the higher instantaneous luminosity and the elevated radiation levels. The active media of the forward backing hadron calorimeters is projected to be radiation-hard, high light yield scintillation materials or similar alternatives. In this context, we have studied various radiation-hard scintillating materials such as Polyethylene Terephthalate (PET), Polyethylene Naphthalate (PEN), High Efficiency Mirror (HEM) and quartz plates with various coatings. The quartz plates are pure Cerenkov radiators and their radiation hardness has been confirmed. In order to increase the light output, we considered organic and inorganic coating materials such as p-Terphenyl (pTp), Anthracene and Gallium-doped Zinc Oxide (ZnO Ga) that are applied as thin layers on the surface of the quartz plates. Here, we present the results of the related test beam activities, laboratory measurements and recent developments.

  3. Structure-property relations in siloxane-based main chain liquid crystalline elastomers and related linear polymers

    Science.gov (United States)

    Ren, Wanting

    2007-12-01

    Soft materials have attracted much scientific and technical interest in recent years. In this thesis, attention has been placed on the underpinning relations between molecular structure and properties of one type of soft matter---main chain liquid crystalline elastomers (MCLCEs), which may have application as shape memory or as auxetic materials. In this work, a number of siloxane-based MCLCEs and their linear polymer analogues (MCLCEs) with chemical variations were synthesized and examined. Among these chemical variations, rigid p-phenylene transverse rod and flat-shaped anthraquinone (AQ) mesogenic monomers were specifically incorporated. Thermal and X-ray analysis found a smectic C phase in most of our MCLCEs, which was induced by the strong self-segregation of siloxane spacers, hydrocarbon spacers and mesogenic rods. The smectic C mesophase of the parent LCE was not grossly affected by terphenyl transverse rods. Mechanical studies of MCLCEs indicated the typical three-region stress-strain curve and a polydomain-to-monodomain transition. Strain recovery experiments of MCLCEs showed a significant dependence of strain retentions on the initial strains but not on the chemical variations, such as the crosslinker content and the lateral substituents on mesogenic rods. The MCLCE with p-phenylene transverse rod showed a highly ordered smectic A mesophase at room temperature with high stiffness. Mechanical properties of MCLCEs with AQ monomers exhibit a strong dependence on the specific combination of hydrocarbon spacer and siloxane spacer, which also strongly affect the formation of pi-pi stacking between AQ units. Poisson's ratio measurement over a wide strain range found distinct trends of Poisson's ratio as a function of the crosslinker content as well as terphenyl transverse rod loadings in its parent MCLCEs.

  4. Experimental and computational investigation of graphene/SAMs/n-Si Schottky diodes

    Science.gov (United States)

    Aydin, H.; Bacaksiz, C.; Yagmurcukardes, N.; Karakaya, C.; Mermer, O.; Can, M.; Senger, R. T.; Sahin, H.; Selamet, Y.

    2018-01-01

    We have investigated the effect of two different self-assembled monolayers (SAMs) on electrical characteristics of bilayer graphene (BLG)/n-Si Schottky diodes. Novel 4″bis(diphenylamino)-1, 1‧:3″-terphenyl-5‧ carboxylic acids (TPA) and 4,4-di-9H-carbazol-9-yl-1,1‧:3‧1‧-terphenyl-5‧ carboxylic acid (CAR) aromatic SAMs have been used to modify n-Si surfaces. Cyclic voltammetry (CV) and Kelvin probe force microscopy (KPFM) results have been evaluated to verify the modification of n-Si surface. The current-voltage (I-V) characteristics of bare and SAMs modified devices show rectification behaviour verifying a Schottky junction at the interface. The ideality factors (n) from ln(I)-V dependences were determined as 2.13, 1.96 and 2.07 for BLG/n-Si, BLG/TPA/n-Si and BLG/CAR/n-Si Schottky diodes, respectively. In addition, Schottky barrier height (SBH) and series resistance (Rs) of SAMs modified diodes were decreased compared to bare diode due to the formation of a compatible interface between graphene and Si as well as π-π interaction between aromatic SAMs and graphene. The CAR-based device exhibits better diode characteristic compared to the TPA-based device. Computational simulations show that the BLG/CAR system exhibits smaller energy-level-differences than the BLG/TPA, which supports the experimental findings of a lower Schottky barrier and series resistance in BLG/CAR diode.

  5. Versatile benzimidazole/triphenylamine hybrids: efficient nondoped deep-blue electroluminescence and good host materials for phosphorescent emitters.

    Science.gov (United States)

    Gong, Shaolong; Zhao, Yongbiao; Wang, Meng; Yang, Chuluo; Zhong, Cheng; Qin, Jingui; Ma, Dongge

    2010-09-03

    Two new bipolar compounds, N,N,N',N'-tetraphenyl-5'-(1-phenyl-1H-benzimidazol-2-yl)-1,1':3',1''-terphenyl-4,4''-diamine (1) and N,N,N',N'-tetraphenyl-5'-(1-phenyl-1H-benzimidazol-2-yl)-1,1':3',1''-terphenyl-3,3''-diamine (2), were synthesized and characterized, and their thermal, photophysical, and electrochemical properties were investigated. Compounds 1 and 2 possess good thermal stability with high glass-transition temperatures of 109-129 degrees C and thermal decomposition temperatures of 501-531 degrees C. The fluorescence quantum yield of 1 (0.52) is higher than that of 2 (0.16), which could be attributed to greater pi conjugation between the donor and acceptor moieties. A nondoped deep-blue fluorescent organic light-emitting diode (OLED) using 1 as the blue emitter displays high performance, with a maximum current efficiency of 2.2 cd A(-1) and a maximum external efficiency of 2.9 % at the CIE coordinates of (0.17, 0.07) that are very close to the National Television System Committee's blue standard (0.15, 0.07). Electrophosphorescent devices using the two compounds as host materials for green and red phosphor emitters show high efficiencies. The best performance of a green phosphorescent device was achieved using 2 as the host, with a maximum current efficiency of 64.3 cd A(-1) and a maximum power efficiency of 68.3 lm W(-1); whereas the best performance of a red phosphorescent device was achieved using 1 as the host, with a maximum current efficiency of 11.5 cd A(-1), and a maximum power efficiency of 9.8 lm W(-1). The relationship between the molecular structures and optoelectronic properties are discussed.

  6. Dependence of surface morphology on molecular structure and its influence on the properties of OLEDs.

    Science.gov (United States)

    Lim, S H; Ryu, G Y; Seo, J H; Park, J H; Youn, S W; Kim, Y K; Shin, D M

    2008-09-01

    Most organic light-emitting diodes (OLEDs) have a multilayer structure composed of organic layers such as a hole injection layer (HIL), a hole transport layer (HTL), an emission layer (EML), an electron transport layer (ETL) and an electron injection layer (EIL) sandwiched between two electrodes. The organic layers are thin solid films with a thickness from a few nano meters to a few tenths nano meter, respectively. Surface morphology of an organic thin solid film in OLEDs depends on the molecular structure of the organic material and has an affect on device performance. To analyze the effect of surface morphology of an organic thin solid film on fluorescence and electroluminescence (EL) properties, thin solid films of 4-(dicyanomethylene)-2-methyl-6-(julolidin-4-yl-vinyl)-4H-pyran (DCM2) and new red fluorophores, (2E,2'E)-3,3'-[4,4''-bis(dimethylamino)-1,1':4',1''-terphenyl-2',5'-diyl]bis[2-(2-thienyl)acrylonitrile] (ABCV-Th) and (2Z,2'Z)-3,3'-[4,4''-bis(dimethylamino)-1,1':4',1''-terphenyl-2',5'-diyl]bis(2-phenylacrylonitrile) (ABCV-P) were investigated by atomic force microscopy (AFM). The samples for EL and AFM measurement were fabricated by the high-vacuum thermal deposition (8 x 10(-7) Torr) of organic materials onto the surface of indium tin oxide (ITO)-coated glass substrate, in which the layer structures of samples for AFM measurement and those for EL measurement were ITO/NPB (40 nm)/red emitters (80 nm) and ITO/NPB (40 nm)/red emitters (80 nm)/BCP (30 nm)/Liq (2 nm)/Al (100 nm), respectively. The analysis based on AFM measurements well supported that the photoluminescence properties and the device performance were very much dependent upon surface morphology of an organic thin layer.

  7. A chalcone showing positional disorder, two related diarylcyclohexenones showing enantiomeric disorder and a related hydroxyterphenyl, all derived from simple carbonyl precursors.

    Science.gov (United States)

    Salian, Vinutha V; Narayana, Badiadka; Yathirajan, Hemmige S; Akkurt, Mehmet; Çelik, Ömer; Ersanlı, Cem Cüneyt; Glidewell, Christopher

    2015-07-01

    Four compounds are reported, all of which lie along a versatile reaction pathway which leads from simple carbonyl compounds to terphenyls. (2E)-1-(2,4-Dichlorophenyl)-3- [4-(prop-1-en-2-yl)phenyl]prop-2-en-1-one, C18H14Cl2O, (I), prepared from 4-(prop-1-en-2-yl)benzaldehyde and 2,4-dichloroacetophenone, exhibits disorder over two sets of atomic sites having occupancies of 0.664 (6) and 0.336 (6). The related chalcone (2E)-3-(4-chlorophenyl)-1-(4-fluorophenyl)prop-2-en-1-one reacts with acetone to produce (5RS)-3-(4-chlorophenyl)-5-[4-(propan-2-yl)phenyl]cyclohex-2-en-1-one, C21H21ClO, (II), which exhibits enantiomeric disorder with occupancies at the reference site of 0.662 (4) and 0.338 (4) for the (5R) and (5S) forms; the same chalcone reacts with methyl 3-oxobutanoate to give methyl (1RS,6SR)-4-(4-chlorophenyl)-6-[4-(propan-2-yl)phenyl]-2-oxocyclohex-3-ene-1-carboxylate, C23H23ClO3, (III), where the reference site contains both (1R,6S) and (1S,6R) forms with occupancies of 0.923 (3) and 0.077 (3), respectively. Oxidation, using 2,3-dichloro-5,6-dicyano-1,4-benzoquinone, of ethyl (1RS,6SR)-6-(4-bromophenyl)-4-(4-fluorophenyl)-2-oxocyclohex-3-ene-1-carboxylate, prepared in a similar manner to (II) and (III), produces ethyl 4''-bromo-4-fluoro-5'-hydroxy-1,1':3',1''-terphenyl-4'-carboxylate, C21H16BrFO3, (IV), which crystallizes with Z' = 2 in the space group P-1. There are no significant intermolecular interactions in the structures of compounds (I) and (II), but for the major disorder component of compound (III), the molecules are linked into sheets by a combination of C-H...O and C-H...π(arene) hydrogen bonds. The two independent molecules of compound (IV) form two different centrosymmetric dimers, one built from inversion-related pairs of C-H...O hydrogen bonds and the other from inversion-related pairs of C-H...π(arene) hydrogen bonds. Comparisons are made with related compounds.

  8. Dependence of surface morphology on molecular structure and its influence on the properties of OLEDs

    Energy Technology Data Exchange (ETDEWEB)

    Lim, S.H. [Department of Chemical Engineering, Hongik University, 72-1, Sangsu-Dong, Mapo-Gu, Seoul 121-791 (Korea, Republic of); Ryu, G.Y. [Department of Electric Information and Control Engineering, Hongik University, 72-1, Sangsu-Dong, Mapo-Gu, Seoul 121-791 (Korea, Republic of); Seo, J.H.; Park, J.H. [Center for Organic Materials and Information Devices (COMID), Hongik University, 72-1, Sangsu-Dong, Mapo-Gu, Seoul 121-791 (Korea, Republic of); Department of Information Display, Hongik University, 72-1, Sangsu-Dong, Mapo-Gu, Seoul 121-791 (Korea, Republic of); Youn, S.W. [Department of Chemical Engineering, Hongik University, 72-1, Sangsu-Dong, Mapo-Gu, Seoul 121-791 (Korea, Republic of); Kim, Y.K. [Center for Organic Materials and Information Devices (COMID), Hongik University, 72-1, Sangsu-Dong, Mapo-Gu, Seoul 121-791 (Korea, Republic of); Department of Information Display, Hongik University, 72-1, Sangsu-Dong, Mapo-Gu, Seoul 121-791 (Korea, Republic of); Shin, D.M. [Department of Chemical Engineering, Hongik University, 72-1, Sangsu-Dong, Mapo-Gu, Seoul 121-791 (Korea, Republic of)], E-mail: shindm@wow.hongik.ac.kr

    2008-09-15

    Most organic light-emitting diodes (OLEDs) have a multilayer structure composed of organic layers such as a hole injection layer (HIL), a hole transport layer (HTL), an emission layer (EML), an electron transport layer (ETL) and an electron injection layer (EIL) sandwiched between two electrodes. The organic layers are thin solid films with a thickness from a few nano meters to a few tenths nano meter, respectively. Surface morphology of an organic thin solid film in OLEDs depends on the molecular structure of the organic material and has an affect on device performance. To analyze the effect of surface morphology of an organic thin solid film on fluorescence and electroluminescence (EL) properties, thin solid films of 4-(dicyanomethylene)-2-methyl-6-(julolidin-4-yl-vinyl)-4H-pyran (DCM2) and new red fluorophores, (2E,2'E)-3,3'-[4,4''-bis(dimethylamino)-1,1':4',1''-terphenyl-2',5'-diyl] bis[2= -(2-thienyl)acrylonitrile] (ABCV-Th) and (2Z,2'Z)-3,3'-[4,4''-bis(dimethylamino)-1,1':4',1''-terphenyl-2',5'-diyl] bis(2-phenylacrylonitrile) (ABCV-P) were investigated by atomic force microscopy (AFM). The samples for EL and AFM measurement were fabricated by the high-vacuum thermal deposition (8x10{sup -7} Torr) of organic materials onto the surface of indium tin oxide (ITO)-coated glass substrate, in which the layer structures of samples for AFM measurement and those for EL measurement were ITO/NPB (40 nm)/red emitters (80 nm) and ITO/NPB (40 nm)/red emitters (80 nm)/BCP (30 nm)/Liq (2 nm)/Al (100 nm), respectively. The analysis based on AFM measurements well supported that the photoluminescence properties and the device performance were very much dependent upon surface morphology of an organic thin layer.

  9. Heterometallic Alkaline Earth-Lanthanide Ba(II)-La(III) Microporous Metal-Organic Framework as Bifunctional Luminescent Probes of Al(3+) and MnO4(.).

    Science.gov (United States)

    Ding, Bin; Liu, Shi Xin; Cheng, Yue; Guo, Chao; Wu, Xiang Xia; Guo, Jian Hua; Liu, Yuan Yuan; Li, Yan

    2016-05-02

    In this work a rigid asymmetrical tricarboxylate ligand p-terphenyl-3,4″,5-tricarboxylic acid (H3L) has been employed, and a unique heterometallic alkaline earth-lanthanide microporous luminescent metal-organic framework (MOF) {[Ba3La0.5(μ3-L)2.5(H2O)3(DMF)]·(3DMF)}n (1·3DMF) (DMF = dimethylformamide) has been isolated under solvothermal conditions. Single-crystal X-ray structural analysis demonstrates that 2D inorganic Ba-O-La connectivity can be observed in 1, which are further bridged via rigid terphenyl backbones of L(3-), forming a unique I(2)O(1)-type microporous luminescent framework. A 1D microporous channel with dimensionality of 9.151(3) Å × 10.098(1) Å can be observed along the crystallographic a axis. PXRD patterns have been investigated indicating pure phases of 1. The luminescence explorations demonstrated that 1 exhibits highly selective and sensitive sensing for Al(3+) over other cations with high quenching efficiency Ksv value of 1.445 × 10(4) L·mol(-1) and low detection limit (1.11 μM (S/N = 3)). Meanwhile 1 also exhibits highly selective and sensitive sensing for MnO4(-) over other anions with quenching efficiency Ksv = 7.73 × 10(3) L·mol(-1) and low detection limit (0.28 μM (S/N = 3)). It is noted that, when different concentrations of MnO4(-) solutions (0.5 to 100 μM) were dropped into the suspension of 1, the bright blue luminescence of the suspension observed under UV light can gradually change into pink color, indicating visually luminescent sensing, which makes the detection process of MnO4(-) more convenient in practical. The result also reveals that 1 represents the first example of bifunctional heterometallic alkaline earth-lanthanide MOF-based luminescent probes for selectively detecting Al(3+) and MnO4(-) in the water solutions.

  10. X-ray excited luminescence of polystyrene composites loaded with SrF{sub 2} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Demkiv, T.M.; Halyatkin, O.O.; Vistovskyy, V.V. [Ivan Franko National University of Lviv, 8a Kyryla i Mefodiya St., 79005 Lviv (Ukraine); Hevyk, V.B. [Ivano-Frankivsk National Technical University of Oil and Gas, 15 Karpatska St., 76019 Ivano-Frankivsk (Ukraine); Yakibchuk, P.M. [Ivan Franko National University of Lviv, 8a Kyryla i Mefodiya St., 79005 Lviv (Ukraine); Gektin, A.V. [Institute for Scintillation Materials, NAS of Ukraine, 60 Lenina Ave, 61001 Kharkiv (Ukraine); Voloshinovskii, A.S. [Ivan Franko National University of Lviv, 8a Kyryla i Mefodiya St., 79005 Lviv (Ukraine)

    2017-03-01

    The polystyrene film nanocomposites of 0.3 mm thickness with embedded SrF{sub 2} nanoparticles up to 40 wt% have been synthesized. The luminescent and kinetic properties of the polystyrene composites with embedded SrF{sub 2} nanoparticles upon the pulse X-ray excitation have been investigated. The luminescence intensity of the pure polystyrene scintillator film significantly increases when it is loaded with the inorganic SrF{sub 2} nanoparticles. The film nanocomposites show fast (∼2.8 ns) and slow (∼700 ns) luminescence decay components typical for a luminescence of polystyrene activators (p-Terphenyl and POPOP) and SrF{sub 2} nanoparticles, respectively. It is revealed that the fast decay luminescence component of the polystyrene composites is caused by the excitation of polystyrene by the photoelectrons escaped from the nanoparticles due to photoeffect, and the slow component is caused by reabsorption of the self-trapped exciton luminescence of SrF{sub 2} nanoparticles by polystyrene.

  11. Properties of kinetic transition networks for atomic clusters and glassy solids.

    Science.gov (United States)

    Morgan, John W R; Mehta, Dhagash; Wales, David J

    2017-09-27

    A database of minima and transition states corresponds to a network where the minima represent nodes and the transition states correspond to edges between the pairs of minima they connect via steepest-descent paths. Here we construct networks for small clusters bound by the Morse potential for a selection of physically relevant parameters, in two and three dimensions. The properties of these unweighted and undirected networks are analysed to examine two features: whether they are small-world, where the shortest path between nodes involves only a small number or edges; and whether they are scale-free, having a degree distribution that follows a power law. Small-world character is present, but statistical tests show that a power law is not a good fit, so the networks are not scale-free. These results for clusters are compared with the corresponding properties for the molecular and atomic structural glass formers ortho-terphenyl and binary Lennard-Jones. These glassy systems do not show small-world properties, suggesting that such behaviour is linked to the structure-seeking landscapes of the Morse clusters.

  12. SNOWMASS WHITE PAPER - SLHC Endcap 1.4

    CERN Document Server

    Bilki, Burak; Winn, David R; Yetkin, Taylan

    2013-01-01

    Radiation damage in the plastic scintillator and/or readout WLS fibers in the HE endcap calorimeter 1.4Terphenyl(pTP) or the fast phosphor ZnO:Ga. These tiles would be read-out by easily replaceable arrays of straight, parallel WLS fibers coupled to clear plastic-cladded quartz fibers of proven radiation resistance. We describe a second alternative with a new absorber matrix extending to 1.4

  13. On-Surface Pseudo-High-Dilution Synthesis of Macrocycles: Principle and Mechanism.

    Science.gov (United States)

    Fan, Qitang; Wang, Tao; Dai, Jingya; Kuttner, Julian; Hilt, Gerhard; Gottfried, J Michael; Zhu, Junfa

    2017-05-23

    Macrocycles have attracted much attention due to their specific "endless" topology, which results in extraordinary properties compared to related linear (open-chain) molecules. However, challenges still remain in their controlled synthesis with well-defined constitution and geometry. Here, we report the successful application of the (pseudo-)high-dilution method to the conditions of on-surface synthesis in ultrahigh vacuum. This approach leads to high yields (up to 84%) of cyclic hyperbenzene ([18]-honeycombene) via an Ullmann-type reaction from 4,4″-dibromo-meta-terphenyl (DMTP) as precursor on a Ag(111) surface. The mechanism of macrocycle formation was explored in detail using scanning tunneling microscopy and X-ray photoemission spectroscopy. We propose that the dominant pathway for hyperbenzene (MTP)6 formation is the stepwise desilverization of an organometallic (MTP-Ag)6 macrocycle, which forms via cyclization of (MTP-Ag)6 chains under pseudo-high-dilution conditions. The high probability of cyclization on the stage of the organometallic phase results from the reversibility of the C-Ag bond. The case is different from that in solution, in which cyclization typically occurs on the stage of a covalently bonded open-chain precursor. This difference in the cyclization mechanism on a surface compared to that in solution stems mainly from the 2D confinement exerted by the surface template, which hinders the flipping of chain segments necessary for cyclization.

  14. Tuning the helicity of self-assembled structure of a sugar-based organogelator by the proper choice of cooling rate.

    Science.gov (United States)

    Cui, Jiaxi; Liu, Anhua; Guan, Yan; Zheng, Jia; Shen, Zhihao; Wan, Xinhua

    2010-03-02

    A novel sugar-appended low-molecular-mass gelator, 4''-butoxy-4-hydroxy-p-terphenyl-beta-D-glucoside (BHTG), was synthesized. It formed thermally reversible gels in a variety of aqueous and organic solvents. Three-dimensional networks made up of helical ribbons were observed in the mixture of H(2)O/1,4-dioxane (40/60 v/v). The handedness of the ribbons depended on the rate of gel formation. Fast-cooling process led to right-handed ribbons, while slow-cooling process led to left-handed ones. A combinatory analyses of microscopic, spectroscopic, and diffraction techniques revealed that BHTG formed a twisted interdigitated bilayer structure with a d spacing of 3.1 nm in gels through a kinetically controlled nucleation-growth process. There were two kinds of molecular orientations of BHTG in the nuclei, clockwise and anticlockwise, which dictated the growth of ribbons. One was metastable and formed first during the cooling process of gel formation. It was able to gradually transform into the more stable latter one with further decreasing temperature. Fast-cooling process did not leave enough time for the nuclei to evolve from metastable to stable state and the ribbons grown from them exhibited right-handedness. However, the metastable nuclei transformed into the stable one when cooled slowly and directed the molecules of BHTG to grow into left-handed aggregates.

  15. Water permeation through anion exchange membranes

    Science.gov (United States)

    Luo, Xiaoyan; Wright, Andrew; Weissbach, Thomas; Holdcroft, Steven

    2018-01-01

    An understanding of water permeation through solid polymer electrolyte (SPE) membranes is crucial to offset the unbalanced water activity within SPE fuel cells. We examine water permeation through an emerging class of anion exchange membranes, hexamethyl-p-terphenyl poly (dimethylbenzimidazolium) (HMT-PMBI), and compare it against series of membrane thickness for a commercial anion exchange membrane (AEM), Fumapem® FAA-3, and a series of proton exchange membranes, Nafion®. The HMT-PMBI membrane is found to possess higher water permeabilities than Fumapem® FAA-3 and comparable permeability than Nafion (H+). By measuring water permeation through membranes of different thicknesses, we are able to decouple, for the first time, internal and interfacial water permeation resistances through anion exchange membranes. Permeation resistances on liquid/membrane interface is found to be negligible compared to that for vapor/membrane for both series of AEMs. Correspondingly, the resistance of liquid water permeation is found to be one order of magnitude smaller compared to that of vapor water permeation. HMT-PMBI possesses larger effective internal water permeation coefficient than both Fumapem® FAA-3 and Nafion® membranes (60 and 18% larger, respectively). In contrast, the effective interfacial permeation coefficient of HMT-PMBI is found to be similar to Fumapem® (±5%) but smaller than Nafion®(H+) (by 14%).

  16. Quantitative interpretation of the transition voltages in gold-poly(phenylene) thiol-gold molecular junctions

    KAUST Repository

    Wu, Kunlin

    2013-01-01

    The transition voltage of three different asymmetric Au/poly(phenylene) thiol/Au molecular junctions in which the central molecule is either benzene thiol, biphenyl thiol, or terphenyl thiol is investigated by first-principles quantum transport simulations. For all the junctions, the calculated transition voltage at positive polarity is in quantitative agreement with the experimental values and shows weak dependence on alterations of the Au-phenyl contact. When compared to the strong coupling at the Au-S contact, which dominates the alignment of various molecular orbitals with respect to the electrode Fermi level, the coupling at the Au-phenyl contact produces only a weak perturbation. Therefore, variations of the Au-phenyl contact can only have a minor influence on the transition voltage. These findings not only provide an explanation to the uniformity in the transition voltages found for π-conjugated molecules measured with different experimental methods, but also demonstrate the advantage of transition voltage spectroscopy as a tool for determining the positions of molecular levels in molecular devices. © 2013 AIP Publishing LLC.

  17. Measurement of Density, Sound Velocity, Surface Tension, and Viscosity of Freely Suspended Supercooled Liquids

    Science.gov (United States)

    Trinh, E. H.

    1995-01-01

    Non-contact methods have been implemented in conjunction with levitation techniques to carry out the measurement of the macroscopic properties of liquids significantly cooled below their nominal melting point. Free suspension of the sample and remote methods allow the deep excursion into the metastable liquid state and the determination of its thermophysical properties. We used this approach to investigate common substances such as water, o-terphenyl, succinonitrile, as well as higher temperature melts such as molten indium, aluminum and other metals. Although these techniques have thus far involved ultrasonic, electromagnetic, and more recently electrostatic levitation, we restrict our attention to ultrasonic methods in this paper. The resulting magnitude of maximum thermal supercooling achieved have ranged between 10 and 15% of the absolute temperature of the melting point for the materials mentioned above. The physical properties measurement methods have been mostly novel approaches, and the typical accuracy achieved have not yet matched their standard equivalent techniques involving contained samples and invasive probing. They are currently being refined, however, as the levitation techniques become more widespread, and as we gain a better understanding of the physics of levitated liquid samples.

  18. A new experimental scheme for nuclear γ -resonance time-domain interferometry

    Science.gov (United States)

    Caporaletti, F.; Chumakov, A. I.; Rüffer, R.; Monaco, G.

    2017-10-01

    Time-domain interferometry (TDI) based on nuclear resonant scattering of synchrotron radiation by Mössbauer nuclei is a promising technique to study slow dynamics at the interatomic length scale. In order to improve the efficiency of this technique, a new TDI scheme is developed involving the use of a nuclear absorber with a two-line energy spectrum combined with a single-line spectrum. Different from other TDI setups, the issue of external vibrations is much reduced since the two absorbers are at rest and no velocity transducer is used. This allows measuring beating patterns with satisfying statistical accuracy and contrast up to 350 ns. We report here the characterization of the experimental setup necessary for the implementation of this new scheme. The model required for the description of the beating pattern produced by a three-line spectrum system is also discussed in detail. Finally, we report some results for the dynamics of the prototypical glass-former ortho-terphenyl to demonstrate the possibilities offered by this new scheme.

  19. Vialinin A, a novel potent inhibitor of TNF-alpha production from RBL-2H3 cells.

    Science.gov (United States)

    Onose, Jun-Ichi; Xie, Chun; Ye, Yue Qi; Sugaya, Kouichi; Takahashi, Shunya; Koshino, Hiroyuki; Yasunaga, Katsuaki; Abe, Naoki; Yoshikawa, Kunie

    2008-05-01

    Thelephora vialis is a mushroom that grows in symbiosis with pine trees in Yunnan, China, a place known to have some of the richest and most diverse bioresources in the world. This is one of the most favored edible mushrooms, due to its flavor. Our screening for bioactive compounds from these mushrooms isolated a novel potent antioxidant, vialinin A, together with known compounds, from the dry fruiting bodies of T. vialis. Vialinin A is a terphenyl derivative and was elucidated by spectroscopic and chemical methods. Vialinin A showed anti-allergic activities, inhibition of beta-hexosaminidase, tumor necrosis factor (TNF)-alpha, interleukin 4 and monocyte chemotactic protein 1 release from RBL-2H3 cells, whereas atromentin and an inseparable mixture of ganbajunins D and E showed no such effects. Vialinin A displayed potent inhibition of TNF-alpha production from RBL-2H3 cells (IC50, 0.09+/-0.01 nM), indicating stronger inhibition than tacrolimus for organ transplantation (IC50, 0.25+/-0.03 nM). The potent inhibitory activities of these compounds against TNF-alpha production indicate promising new candidates for anti-allergic agents.

  20. Exploring NMR ensembles of calcium binding proteins: Perspectives to design inhibitors of protein-protein interactions

    Directory of Open Access Journals (Sweden)

    Craescu Constantin T

    2011-05-01

    Full Text Available Abstract Background Disrupting protein-protein interactions by small organic molecules is nowadays a promising strategy employed to block protein targets involved in different pathologies. However, structural changes occurring at the binding interfaces make difficult drug discovery processes using structure-based drug design/virtual screening approaches. Here we focused on two homologous calcium binding proteins, calmodulin and human centrin 2, involved in different cellular functions via protein-protein interactions, and known to undergo important conformational changes upon ligand binding. Results In order to find suitable protein conformations of calmodulin and centrin for further structure-based drug design/virtual screening, we performed in silico structural/energetic analysis and molecular docking of terphenyl (a mimicking alpha-helical molecule known to inhibit protein-protein interactions of calmodulin into X-ray and NMR ensembles of calmodulin and centrin. We employed several scoring methods in order to find the best protein conformations. Our results show that docking on NMR structures of calmodulin and centrin can be very helpful to take into account conformational changes occurring at protein-protein interfaces. Conclusions NMR structures of protein-protein complexes nowadays available could efficiently be exploited for further structure-based drug design/virtual screening processes employed to design small molecule inhibitors of protein-protein interactions.

  1. Transition from Arrhenius to non-Arrhenius temperature dependence of structural relaxation time in glass-forming liquids: continuous versus discontinuous scenario.

    Science.gov (United States)

    Popova, V A; Surovtsev, N V

    2014-09-01

    The temperature dependences of α relaxation time τ(α)(T) of three glass-forming liquids (salol, o-terphenyl, and α-picoline) were investigated by a depolarized light scattering technique. A detailed description of τ(α)(T) near T(A), the temperature of the transition from the Arrhenius law at high temperatures to a non-Arrhenius behavior of τ(α)(T) at lower temperatures, was done. It was found that this transition is quite sharp. If the transition is described as switching from the Arrhenius law to the Vogel-Fulcher-Tammann law, it occurs within the temperature range of about 15 K or less. Most of the known expressions for τ(α)(T) cannot describe this sharp transition. Our analysis revealed that this transition can be described either as a discontinuous transition in the spirit of the frustration-limited domain theory [D. Kivelson, G. Tarjus, X. Zhao, and S. A. Kivelson, Phys. Rev. E 53, 751 (1996)], implying a phase transition, or by a phenomenological expression recently suggested [B. Schmidtke, N. Petzold, R. Kahlau, M. Hofmann, and E. A. Rössler, Phys. Rev. E 86, 041507 (2012)], where the activation energy includes the term depending exponentially on temperature.

  2. Intraoperative probe detecting β{sup −} decays in brain tumour radio-guided surgery

    Energy Technology Data Exchange (ETDEWEB)

    Solfaroli Camillocci, E., E-mail: elena.solfaroli@roma1.infn.it [Dip. Fisica, Sapienza Univ. di Roma, Roma (Italy); INFN Sezione di Roma, Roma (Italy); Bocci, V.; Chiodi, G. [INFN Sezione di Roma, Roma (Italy); Collamati, F. [INFN Sezione di Roma, Roma (Italy); Dip. Scienze di Base e Applicate per l' Ingegneria, Sapienza Univ. di Roma, Roma (Italy); Donnarumma, R.; Faccini, R.; Mancini Terracciano, C. [Dip. Fisica, Sapienza Univ. di Roma, Roma (Italy); INFN Sezione di Roma, Roma (Italy); Marafini, M. [INFN Sezione di Roma, Roma (Italy); Museo Storico della Fisica e Centro Studi e Ricerche ‘E. Fermi’, Roma (Italy); Mattei, I.; Muraro, S. [Center for Life Nano Science@Sapienza, Istituto Italiano di Tecnologia, Roma (Italy); Recchia, L. [INFN Sezione di Roma, Roma (Italy); Rucinski, A. [INFN Sezione di Roma, Roma (Italy); Dip. Scienze di Base e Applicate per l' Ingegneria, Sapienza Univ. di Roma, Roma (Italy); Russomando, A. [Dip. Fisica, Sapienza Univ. di Roma, Roma (Italy); INFN Sezione di Roma, Roma (Italy); Center for Life Nano Science@Sapienza, Istituto Italiano di Tecnologia, Roma (Italy); Toppi, M. [Laboratori Nazionali di Frascati dell' INFN, Frascati (Italy); Traini, G. [Dip. Fisica, Sapienza Univ. di Roma, Roma (Italy); INFN Sezione di Roma, Roma (Italy); Morganti, S. [INFN Sezione di Roma, Roma (Italy)

    2017-02-11

    Radio-guided surgery (RGS) is a technique to intraoperatively detect tumour remnants, favouring a radical resection. Exploiting β{sup −} emitting tracers provides a higher signal to background ratio compared to the established technique with γ radiation, allowing the extension of the RGS applicability range. We developed and tested a detector based on para-terphenyl scintillator with high sensitivity to low energy electrons and almost transparent to γs to be used as intraoperative probe for RGS with β{sup −} emitting tracer. Portable read out electronics was customised to match the surgeon needs. This probe was used for preclinical test on specific phantoms and a test on “ex vivo” specimens from patients affected by meningioma showing very promising results for the application of this new technique on brain tumours. In this paper, the prototype of the intraoperative probe and the tests are discussed; then, the results on meningioma are used to make predictions on the performance of the probe detecting residuals of a more challenging and more interesting brain tumour: the glioma.

  3. Three new solvent-directed Cd(II)-based MOFs with unique luminescent properties and highly selective sensors for Cu(2+) cations and nitrobenzene.

    Science.gov (United States)

    Wu, Yunlong; Yang, Guo-Ping; Zhao, Yanqing; Wu, Wei-Ping; Liu, Bo; Wang, Yao-Yu

    2015-02-21

    Three new solvent-induced metal-organic frameworks (MOFs)-[Cd(H2L)(H2O)3]·NMP (), [Cd3(L)(H2O)4(OH)2] () and [Cd(L)0.5(H2O)]·H2O ()-were designed and successfully prepared via solvothermal reaction by multidentate phenyltetracarboxylic acid [1,1':4',1''-terphenyl]-2',3,3'',5'-tetracarboxylic acid (H4L) and Cd(ii) salts in various solvent systems. Structural analyses indicated that the H2L/L ligands took three different coordination fashions in , and thus resulted in diversity of the targeted MOFs. Solid-state luminescent properties of the three MOFs were studied under ultraviolet light irradiation at ambient temperature; in particular showed high selectivity and sensitivity for Cu(2+) ions and nitrobenzene because of the quenching effect, which thus could make it a potential crystalline material for detecting these substances. The mechanisms of the quenching effect and sensing properties of are discussed in detail.

  4. Effect of Low-Concentration Polymers on Crystal Growth in Molecular Glasses: A Controlling Role for Polymer Segmental Mobility Relative to Host Dynamics.

    Science.gov (United States)

    Huang, Chengbin; Powell, C Travis; Sun, Ye; Cai, Ting; Yu, Lian

    2017-03-02

    Low-concentration polymers can strongly influence crystal growth in small-molecule glasses, a phenomenon important for improving physical stability against crystallization. We measured the velocity of crystal growth in two molecular glasses, nifedipine (NIF) and o-terphenyl (OTP), each doped with four or five different polymers. For each polymer, the concentration was fixed at 1 wt % and a wide range of molecular weights was tested. We find that a polymer additive can strongly alter the rate of crystal growth, from a 10-fold reduction to a 10-fold increase. For a given polymer, increasing molecular weight slows down crystal growth and the effect saturates around DP = 100, where DP is the degree of polymerization. For all the systems studied, the polymer effect on crystal growth rate forms a master curve in the variable (Tg,polymer - Tg,host)/Tcryst, where Tg is the glass transition temperature and Tcryst is the crystallization temperature. These results support the view that a polymer's effect on crystal growth is controlled by its segmental mobility relative to the host-molecule dynamics. In the proposed model, crystal growth rejects impurities and creates local polymer-rich regions, which must be traversed by host molecules to sustain crystal growth at rates determined by polymer segmental mobility. Our results do not support the view that host-polymer hydrogen bonding plays a controlling role in crystal growth inhibition.

  5. Theoretical studies of homogeneous catalysts mimicking nitrogenase.

    Science.gov (United States)

    Sgrignani, Jacopo; Franco, Duvan; Magistrato, Alessandra

    2011-01-10

    The conversion of molecular nitrogen to ammonia is a key biological and chemical process and represents one of the most challenging topics in chemistry and biology. In Nature the Mo-containing nitrogenase enzymes perform nitrogen 'fixation' via an iron molybdenum cofactor (FeMo-co) under ambient conditions. In contrast, industrially, the Haber-Bosch process reduces molecular nitrogen and hydrogen to ammonia with a heterogeneous iron catalyst under drastic conditions of temperature and pressure. This process accounts for the production of millions of tons of nitrogen compounds used for agricultural and industrial purposes, but the high temperature and pressure required result in a large energy loss, leading to several economic and environmental issues. During the last 40 years many attempts have been made to synthesize simple homogeneous catalysts that can activate dinitrogen under the same mild conditions of the nitrogenase enzymes. Several compounds, almost all containing transition metals, have been shown to bind and activate N₂ to various degrees. However, to date Mo(N₂)(HIPTN)₃N with (HIPTN)₃N= hexaisopropyl-terphenyl-triamidoamine is the only compound performing this process catalytically. In this review we describe how Density Functional Theory calculations have been of help in elucidating the reaction mechanisms of the inorganic compounds that activate or fix N₂. These studies provided important insights that rationalize and complement the experimental findings about the reaction mechanisms of known catalysts, predicting the reactivity of new potential catalysts and helping in tailoring new efficient catalytic compounds.

  6. Theoretical Studies of Homogeneous Catalysts Mimicking Nitrogenase

    Directory of Open Access Journals (Sweden)

    Alessandra Magistrato

    2011-01-01

    Full Text Available The conversion of molecular nitrogen to ammonia is a key biological and chemical process and represents one of the most challenging topics in chemistry and biology. In Nature the Mo-containing nitrogenase enzymes perform nitrogen ‘fixation’ via an iron molybdenum cofactor (FeMo-co under ambient conditions. In contrast, industrially, the Haber-Bosch process reduces molecular nitrogen and hydrogen to ammonia with a heterogeneous iron catalyst under drastic conditions of temperature and pressure. This process accounts for the production of millions of tons of nitrogen compounds used for agricultural and industrial purposes, but the high temperature and pressure required result in a large energy loss, leading to several economic and environmental issues. During the last 40 years many attempts have been made to synthesize simple homogeneous catalysts that can activate dinitrogen under the same mild conditions of the nitrogenase enzymes. Several compounds, almost all containing transition metals, have been shown to bind and activate N2 to various degrees. However, to date Mo(N2(HIPTN3N with (HIPTN3N= hexaisopropyl-terphenyl-triamidoamine is the only compound performing this process catalytically. In this review we describe how Density Functional Theory calculations have been of help in elucidating the reaction mechanisms of the inorganic compounds that activate or fix N2. These studies provided important insights that rationalize and complement the experimental findings about the reaction mechanisms of known catalysts, predicting the reactivity of new potential catalysts and helping in tailoring new efficient catalytic compounds.

  7. New deep blue emitting materials based on indenopyrazine core with high thermal stability.

    Science.gov (United States)

    Seok, Chang-Hun; Park, Young-Il; Kim, Soo-Kang; Lee, Ji-Hoon; Park, Jongwook

    2011-05-01

    New deep blue emitting materials 2,8-bis(3,5-diphenylphenyl)-6,6,12,12-tetraethyl-6,12-dihydrodiindeno[1,2-b:1',2'-e]pyrazine (DPP-EPY) and 2,8-bis(3',5'-diphenylbiphenyl-4-yl)-6,6,12,12-tetraethyl-6,12-dihydrodiindeno[1,2-b:1',2'-e]pyrazine (DPBP-EPY) were synthesized through introduction of m-terphenyl or triphenylbenzene bulky side groups in a new indenopyrazine core. These materials all showed high thermal stability and highly reduced intermolecular interaction. DPP-EPY and DPBP-EPY showed PL maxima of 456 nm and 460 nm in deep blue region and narrow PL spectra with full-width at half-maximum (FWHM) of 46 nm and 52 nm, respectively. As a result of making non-doped OLED devices using these synthesized materials as emitting layers, DPP-EPY showed EL spectrum of 452 nm, very narrow FWHM of 46 nm, luminance efficiency of 1.04 cd/A with current density of 10 mA/cm2 and CIE coordinate of (0.161, 0.104), creating a deep blue OLED close to the National Television System Committee (NTSC) blue standard.

  8. Highly Efficient Deep-Blue Electroluminescence from a Charge-Transfer Emitter with Stable Donor Skeleton.

    Science.gov (United States)

    Chen, Wen-Cheng; Yuan, Yi; Ni, Shao-Fei; Zhu, Ze-Lin; Zhang, Jinfeng; Jiang, Zuo-Quan; Liao, Liang-Sheng; Wong, Fu-Lung; Lee, Chun-Sing

    2017-03-01

    Organic materials containing arylamines have been widely used as hole-transporting materials as well as emitters in organic light-emitting devices (OLEDs). However, it has been pointed out that the C-N bonds in these arylamines can easily suffer from degradation in excited states, especially in deep-blue OLEDs. In this work, phenanthro[9,10-d]imidazole (PI) is proposed as a potential donor with higher stability than those of arylamines. Using PI as the donor, a donor-acceptor type deep-blue fluorophore 1-phenyl-2-(4″-(1-phenyl-1H-benzo[d]imidazol-2-yl)-[1,1':4',1″-terphenyl]-4-yl)-1H-phenanthro[9,10-d]imidazole (BITPI) is designed and synthesized. Results from UV-aging test on neat films of BITPI and other three arylamine compounds demonstrate that PI is indeed a more stable donor comparing to common arylamines. An OLED using BITPI as an emitter exhibits good device performances (EQE over 7%) with stable deep-blue emission (color index: (0.15, 0.13)) and longer operation lifetime than the similarly structured device using arylamine-based emitter. Single-organic layer device based on BITPI also shows superior performances, which are comparable to the best results from the arylamine-based donor-acceptor emitters, suggesting that PI is a stable donor with good hole transport/injection capability.

  9. Systematic Design of Pore Size and Functionality in Isoreticular MOFs and Their Application in Methane Storage

    Science.gov (United States)

    Eddaoudi, Mohamed; Kim, Jaheon; Rosi, Nathaniel; Vodak, David; Wachter, Joseph; O'Keeffe, Michael; Yaghi, Omar M.

    2002-01-01

    A strategy based on reticulating metal ions and organic carboxylate links into extended networks has been advanced to a point that allowed the design of porous structures in which pore size and functionality could be varied systematically. Metal-organic framework (MOF-5), a prototype of a new class of porous materials and one that is constructed from octahedral Zn-O-C clusters and benzene links, was used to demonstrate that its three-dimensional porous system can be functionalized with the organic groups -Br, -NH2, -OC3H7, -OC5H11, -C2H4, and -C4H4 and that its pore size can be expanded with the long molecular struts biphenyl, tetrahydropyrene, pyrene, and terphenyl. We synthesized an isoreticular series (one that has the same framework topology) of 16 highly crystalline materials whose open space represented up to 91.1% of the crystal volume, as well as homogeneous periodic pores that can be incrementally varied from 3.8 to 28.8 angstroms. One member of this series exhibited a high capacity for methane storage (240 cubic centimeters at standard temperature and pressure per gram at 36 atmospheres and ambient temperature), and others the lowest densities (0.41 to 0.21 gram per cubic centimeter) for a crystalline material at room temperature.

  10. Study of polystyrene scintillators-WLS fiber elements and scintillating tile-WLS prototypes for New CHOD detector of CERN NA-62 experiment

    CERN Document Server

    Semenov, Vitaliy; Gorin, Aleksandr; Khudyakov, Aleksey; Rykalin, Vladimir; Yushchenko, Oleg

    2016-01-01

    We measured the light output and the time resolution of few sets comprised of polystyrene scintillator and wavelength shifting (WLS) fibers as readout. The samples of different thickness (7-30 mm) have been made in the shape of bricks and plates with the areas of 25×80, 108×134 and 108×268 of mm2. In addition to samples of “ordinary” scintillator with additions of 2% p- Terphenyl + 0.05% POPOP, the rapid ultraviolet scintillator with single 2% additive PBD was tested. For the light collection WLS-fibers BCF92, Y11 and scintillation fiber SCSF-78M as reemitting were checked. The fibers were glued into the grooves on the front surface of scintillators. As the photo detectors silicon photomultipliers (SiPM) produced by CPTA (Russia) and SensL (Ireland) were used. It is shown that the dependence of light output on the thickness of scintillator is nonlinear and close to the square root function, which is also confirmed by the calculations carried out by Monte Carlo. The measured value of a light output make...

  11. Terminal Alkyne Coupling on a Corrugated Noble Metal Surface: From Controlled Precursor Alignment to Selective Reactions.

    Science.gov (United States)

    Lin, Tao; Zhang, Liding; Björk, Jonas; Chen, Zhi; Ruben, Mario; Barth, Johannes V; Klappenberger, Florian

    2017-11-07

    Surface-templated covalent coupling of organic precursors currently emerges as a promising route to the atom-precise fabrication of low-dimensional carbon materials. Here, we investigate the adsorption and the coupling reactions of 4,4''-diethynyl-1,1':4',1''-terphenyl on Au(110) under ultra-high vacuum conditions by using scanning tunneling microscopy combined with density functional theory and kinetic Monte Carlo calculations. Temperature treatment induces both 1,2,4-asymmetric cyclotrimerization and homocoupling, resulting in various reaction products, including a previously unreported, surface-templated H-shaped pentamer. Our analysis of the temperature-dependent relative product abundances unravels that 1,2,4-trimerization and homocoupling proceed via identical intermediate species with the final products depending on the competition of coupling to a third monomer versus dehydrogenation. Our study sheds light on the control of coupling reactions by corrugated surfaces and annealing protocols. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Fast Surface Diffusion and Crystallization of Amorphous Griseofulvin.

    Science.gov (United States)

    Huang, Chengbin; Ruan, Shigang; Cai, Ting; Yu, Lian

    2017-10-12

    Among molecular glasses, griseofulvin (GSF) is one of the fastest crystallizing. To understand this property, we have measured the surface diffusion in GSF using the method of surface grating decay. Surface diffusion in amorphous GSF is extremely fast, outpacing bulk diffusion by a factor of 10(8) at the glass transition temperature Tg (361 K). Among all molecular glasses studied (13 in all), GSF has the second fastest surface diffusion (to o-terphenyl) when compared at Tg. The GSF result fits the overall trend for molecular glasses without intermolecular hydrogen bonds, where surface diffusion systematically slows down with increasing molecular size. This result is particularly noteworthy because GSF has many hydrogen-bond acceptors but no donors, indicating that, so long as they do not participate in hydrogen bonding, the polar functional groups have a similar effect on surface diffusion as the nonpolar hydrocarbon groups. In contrast, the formation of intermolecular hydrogen bonds strongly inhibits surface diffusion. The surface crystal growth rate of amorphous GSF is nearly proportional to its surface diffusion coefficient, as noted for other systems, supporting the view that surface crystal growth is controlled by surface diffusion. In addition, the fast surface diffusion of GSF glasses explains the fast crystal growth along fracture surfaces and suggests a basis to understand fast crystal growth in the bulk through continuous creation of microcracks.

  13. 2,2′-(Disulfanediylbis[4,6-(4-fluorophenylpyrimidine

    Directory of Open Access Journals (Sweden)

    Richard Betz

    2012-02-01

    Full Text Available The title compound, C32H18F4N4S2, is a disulfide symmetrically substituted with two diaza-meta-terphenyl groups. In the crystal, the molecule adopts a twisted conformation with a C—S—S—C torsion angle of −91.82 (7°. One of the 4,6-(4-fluorophenylpyrimidine groups is virtually planar, with dihedral angles between the pyrimidine and benzene groups of 4.00 (8 and 5.44 (8°, wheares the other is non-planar with analogues dihedral angles of 18.69 (8 and 26.60 (8°. The planar 4,6-(4-fluorophenylpyrimidine groups are involved in π–π stacking interactions via their 4-fluorophenyl groups [centroid–centroid distances of 3.8556 (11 and 3.9284 (11 Å] that assemble the molecules into columns extended along the a axis. In addition, the structure is stabilized by C—F...π [F...centroid = 3.4017 (16 Å], C—H...F and C—H...π interactions.

  14. Gas adsorption and structural diversity in a family of Cu(II) pyridyl-isophthalate metal-organic framework materials

    Science.gov (United States)

    Gould, Jamie A.; Athwal, Harprit Singh; Blake, Alexander J.; Lewis, William; Hubberstey, Peter; Champness, Neil R.; Schröder, Martin

    2017-01-01

    A family of Cu(II)-based metal-organic frameworks (MOFs) has been synthesized using three pyridyl-isophthalate ligands, H2L1 (4'-(pyridin-4-yl)biphenyl-3,5-dicarboxylic acid), H2L2 (4''-(pyridin-4-yl)-1,1':4',1''-terphenyl-3,5-dicarboxylic acid) and H2L3 (5-[4-(pyridin-4-yl)naphthalen-1-yl]benzene-1,3-dicarboxylic acid). Although in each case the pyridyl-isophthalate ligands adopt the same pseudo-octahedral [Cu2(O2CR)4N2] paddlewheel coordination modes, the resulting frameworks are structurally diverse, particularly in the case of the complex of Cu(II) with H2L3, which leads to three distinct supramolecular isomers, each derived from Kagomé and square nets. In contrast to [Cu(L2)] and the isomers of [Cu(L3)], [Cu(L1)] exhibits permanent porosity. Thus, the gas adsorption properties of [Cu(L1)] were investigated with N2, CO2 and H2, and the material exhibits an isosteric heat of adsorption competitive with leading MOF sorbents for CO2. [Cu(L1)] displays high H2 adsorption, with the density in the pores approaching that of liquid H2. This article is part of the themed issue 'Coordination polymers and metal-organic frameworks: materials by design'.

  15. Direct spectroscopic observation of quantum jumps of a single molecule

    Science.gov (United States)

    Basché, Th.; Kummer, S.; Bräuchle, C.

    1995-01-01

    BOHR'S notion of quantum jumps between electronic states of an excited atom has now been demonstrated experimentally for single ions confined in radio-frequency traps and interacting with a driving laser field1-3. In these experiments the fluorescence of a strongly allowed transition was shown to cease abruptly when the ion jumped into a metastable state which was coupled to the common electronic ground state by a weak radiative transition. But attempts to monitor quantum jumps of single molecules have been hampered by the fact that the lifetime of the metastable triplet state was too short in relation to the photon detection rate. By using a system with favourable photophysical parameters-terrylene doped into p-terphenyl crystals4-we have now been able to observe directly quantum jumps between electronic states of single terrylene molecules. In contrast to single atoms, here the quantum jumps occur as non-radiative transitions between states of different multiplicity, and are manifested as interruptions of the fluorescence signal. These results demonstrate how single-molecule spectros-copy can reveal truly quantum-mechanical effects in large polyatomic molecules.

  16. Rigid molecular foams

    Energy Technology Data Exchange (ETDEWEB)

    Steckle, W.P. Jr. [Los Alamos National Lab., NM (United States); Mitchell, M.A. [Chemidal Corp., Palatine, IL (United States); Aspen, P.G. [Simula Inc., Phoenix, AZ (United States)

    1998-12-31

    This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). Organic analogues to inorganic zeolites would be a significant step forward in engineered porous materials and would provide advantages in range, selectivity, tailorability, and processing. Rigid molecular foams or {open_quotes}organic zeolites{close_quotes} would not be crystalline materials and could be tailored over a broader range of pore sizes and volumes. A novel process for preparing hypercrosslinked polymeric foams has been developed via a Friedel-Crafts polycondensation reaction. A series of rigid hypercrosslinked foams have been prepared using simple rigid polyaromatic hydrocarbons including benzene, biphenyl, m-terphenyl, diphenylmethane, and polystyrene, with dichloroxylene (DCX) as the pore size. After drying the foams are robust and rigid. Densities of the resulting foams can range from 0.15 g/cc to 0.75 g/cc. Nitrogen adsorption studies have shown that by judiciously selecting monomers and the crosslinking agent along with the level of crosslinking and the cure time of the resulting gel, the pore size, pore size distribution, and the total surface area of the foam can be tailored. Surface areas range from 160 to 1,200 m{sup 2}/g with pore sizes ranging from 6 {angstrom} to 2,000 {angstrom}.

  17. Synthesis and characterization of titania-based monodisperse fluorescent europium nanoparticles for biolabeling

    Energy Technology Data Exchange (ETDEWEB)

    Tan Mingqian [Department of Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, Dalian 116023 (China); Wang Guilan [Department of Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, Dalian 116023 (China); Ye Zhiqiang [Department of Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, Dalian 116023 (China); Yuan Jingli [Department of Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, Dalian 116023 (China)]. E-mail: jingliyuan@yahoo.com.cn

    2006-03-15

    Inorganic-organic hybrid titania-based nanoparticles covalently bound to a fluorescent Eu{sup 3+} chelate of 4,4'-bis(1'',1'',1'',2'',2'',3'',3''-heptafluoro-4'',6''-hexanedion-6''-yl) chlorosulfo-o-terphenyl (BHHCT-Eu{sup 3+}) were synthesized by a sol-gel technique. A conjugate of BHHCT with 3-[2-(2-aminoethylamino) ethylamino]propyl-trimethoxysilane (APTS) was used as a precursor for the nanoparticle preparation and monodisperse nanoparticles consisting of titania network and silica sub-network covalently bound to the Eu{sup 3+} chelate were prepared by the copolymerization of APTS-BHHCT conjugate, titanium tetraisopropoxide (TTIP) and free APTS in EuCl{sub 3} water-alcohol solution. The effects of reaction conditions on size and fluorescence lifetime of the nanoparticles were investigated. The characterizations by transmission electron microscopy and fluorometric methods indicate that the nanoparticles are near spherical and strongly fluorescent having a fluorescence quantum yield of 11.6% and a long fluorescence lifetime of {approx}0.4 ms. The direct-introduced amino groups on the nanoparticle's surface by using free APTS in nanoparticle preparation facilitated the biolabeling process of the nanoparticles. The nanoparticle-labeled streptavidin (SA) was prepared and used in a sandwich-type time-resolved fluoroimmunoassay (TR-FIA) of human prostate-specific antigen (PSA) by using a 96-well microtiter plate as the solid phase carrier. The method gives a detection limit of 66 pg/ml for the PSA assay.

  18. Preparations for the Advanced Scintillator Compton Telescope (ASCOT) balloon flight

    Science.gov (United States)

    Sharma, T.; Bloser, P. F.; Legere, J. S.; Bancroft, C. M.; McConnell, M. L.; Ryan, J. M.; Wright, A. M.

    2017-08-01

    We describe our ongoing work to develop a new medium-energy gamma-ray Compton telescope using advanced scintillator materials combined with silicon photomultiplier readouts and fly it on a scientific balloon. There is a need in high-energy astronomy for a medium-energy gamma-ray mission covering the energy range from approximately 0.4 - 20 MeV to follow the success of the COMPTEL instrument on CGRO. We believe that directly building on the legacy of COMPTEL, using relatively robust, low-cost, off-the-shelf technologies, is the most promising path for such a mission. Fortunately, high-performance scintillators, such as Cerium Bromide (CeBr3) and p-terphenyl, and compact readout devices, such as silicon photomultipliers (SiPMs), are already commercially available and capable of meeting this need. We are now constructing an Advanced Scintillator Compton Telescope (ASCOT) with SiPM readout, with the goal of imaging the Crab Nebula at MeV energies from a high-altitude balloon flight. We expect a 4-sigma detection at 1 MeV in a single transit. We present calibration results of the detector modules, and updated simulations of the balloon instrument sensitivity. If successful, this project will demonstrate that the energy, timing, and position resolution of this technology are sufficient to achieve an order of magnitude improvement in sensitivity in the medium-energy gamma-ray band, were it to be applied to a 1 cubic meter instrument on a long-duration balloon or Explorer platform.

  19. A novel metal-organic framework for high storage and separation of acetylene at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Xing, E-mail: star1987@hdu.edu.cn [College of Materials & Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310027 (China); Wang, Huizhen [State Key Laboratory of Silicon Materials, Cyrus Tang Center for Sensor Materials and Applications, School of Materials Science & Engineering, Zhejiang University, Hangzhou 310027 (China); Ji, Zhenguo [College of Materials & Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310027 (China); Cui, Yuanjing; Yang, Yu [State Key Laboratory of Silicon Materials, Cyrus Tang Center for Sensor Materials and Applications, School of Materials Science & Engineering, Zhejiang University, Hangzhou 310027 (China); Qian, Guodong, E-mail: gdqian@zju.edu.cn [State Key Laboratory of Silicon Materials, Cyrus Tang Center for Sensor Materials and Applications, School of Materials Science & Engineering, Zhejiang University, Hangzhou 310027 (China)

    2016-09-15

    A novel 3D microporous metal-organic framework with NbO topology, [Cu{sub 2}(L)(H{sub 2}O){sub 2}]∙(DMF){sub 6}·(H{sub 2}O){sub 2} (ZJU-10, ZJU = Zhejiang University; H{sub 4}L =2′-hydroxy-[1,1′:4′,1″-terphenyl]-3,3″,5,5″-tetracarboxylic acid; DMF =N,N-dimethylformamide), has been synthesized and structurally characterized. With suitable pore sizes and open Cu{sup 2+} sites, ZJU-10a exhibits high BET surface area of 2392 m{sup 2}/g, as well as moderately high C{sub 2}H{sub 2} volumetric uptake capacity of 132 cm{sup 3}/cm{sup 3}. Meanwhile, ZJU-10a is a promising porous material for separation of acetylene from methane and carbon dioxide gas mixtures at room temperature. - Graphical abstract: A new NbO-type microporous metal-organic framework ZJU-10 with suitable pore size and open Cu{sup 2+} sites was synthesized to realize the strong interaction with acetylene molecules, which can separate the acetylene from methane and carbon dioxane gas mixtures at room temperature. Display Omitted - Highlights: • A novel 3D NbO-type microporous metal-organic framework ZJU-10 was solvothermally synthesized and structurally characterized. • ZJU-10a exhibits high BET surface area of 2392 m{sup 2}/g. • ZJU-10a shows a moderately high C{sub 2}H{sub 2} gravimetric (volumetric) uptake capacity of 174 (132) cm{sup 3}/g at 298 K and 1 bar. • ZJU-10a can separate acetylene from methane and carbon dioxide gas mixtures at room temperature.

  20. Exploring the Influence of the Aromaticity on the Anticancer and Antivascular Activities of Organoplatinum(II) Complexes.

    Science.gov (United States)

    Zamora, Ana; Pérez, Sergio A; Rothemund, Matthias; Rodríguez, Venancio; Schobert, Rainer; Janiak, Christoph; Ruiz, José

    2017-04-24

    A series of new organometallic PtII complexes of the type [Pt(C^N)Cl(DMSO)] (C^N=N,N-dimethyl-1-(2-aryl)methanamine-κ2 C2,N; aryl=phenyl 2 a, biphenyl 2 b, p-terphenyl 2 c, naphthyl 2 d, anthracenyl 2 e, or pyrenyl 2 f) have been synthesized to explore the influence of the aromaticity on their anticancer activity. The best performers, 2 b and d, are more active than cisplatin (CDDP) in epithelial ovarian carcinoma cells A2780, with 2 d having a higher selectivity factor than CDDP in all the tested cell lines. In addition, all the new compounds overcome the acquired resistance in A2780cisR cells and interestingly, show low micromolar IC50 values towards the triple negative breast cancer cell line MDA-MB-231 and the highly metastatic 518A2 melanoma cells. This study shows that the hydrophobicity, accumulation into cells, and metal levels on nuclear DNA for the complexes are consistent with their cytotoxicity. Complexes 2 b and d induce apoptosis in a caspase-independent manner and suppress the intracellular ROS generation without modifying the mitochondria membrane potential. In addition, 2 a-f effectively inhibit angiogenesis in the endothelial cell line EA.hy926 at sub-cytotoxic concentrations and 2 b and d show in vivo antivascular effects on the chorioallantoic membrane (CAM) of fertilized SPF-eggs (SPF=specific-pathogen-free). Inhibition of tubulin polymerization and degeneration of cytoskeleton organization in 518A2 melanoma cells are presented as a preliminary mechanism of its antimetastatic activity. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Persistent organic pollutants in biota samples collected during the Ymer-80 expedition to the Arctic

    Directory of Open Access Journals (Sweden)

    Henrik Kylin

    2015-10-01

    Full Text Available During the 1980 expedition to the Arctic with the icebreaker Ymer, a number of vertebrate species were sampled for determination of persistent organic pollutants. Samples of Arctic char (Salvelinus alpinus, n=34, glaucous gull (Larus hyperboreus, n=8, common eider (Somateria mollissima, n=10, Brünnich's guillemot (Uria lomvia, n=9, ringed seal (Pusa hispida, n=2 and polar bear (Ursus maritimus, n=2 were collected. With the exception of Brünnich's guillemot, there was a marked contamination difference of birds from western as compared to eastern/northern Svalbard. Samples in the west contained a larger number of polychlorinated biphenyl (PCB congeners and also polychlorinated terphenyls, indicating local sources. Brünnich's guillemots had similar pollutant concentrations in the west and east/north; possibly younger birds were sampled in the west. In Arctic char, pollutant profiles from lake Linnévatn (n=5, the lake closest to the main economic activities in Svalbard, were similar to profiles in Arctic char from the Shetland Islands (n=5, but differed from lakes to the north and east in Svalbard (n=30. Arctic char samples had higher concentrations of hexachlorocyclohexanes (HCHs than the marine species of birds and mammals, possibly due to accumulation via snowmelt. Compared to the Baltic Sea, comparable species collected in Svalbard had lower concentrations of PCB and dichlorodiphenyltrichloroethane (DDT, but similar concentrations indicating long-range transport of hexachlorobenzene, HCHs and cyclodiene pesticides. In samples collected in Svalbard in 1971, the concentrations of PCB and DDT in Brünnich's guillemot (n=7, glaucous gull (n=2 and polar bear (n=2 were similar to the concentrations found in 1980.

  2. Self-assembly of aromatic-functionalized amphiphiles: The role and consequences of aromatic-aromatic noncovalent interactions in building supramolecular aggregates and novel assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Whitten, D.G.; Chen, L.; Geiger, H.C.; Perlstein, J.; Song, X. [Los Alamos National Lab., NM (United States). Chemical Science and Technology Div.]|[Univ. of Rochester, NY (United States)

    1998-12-10

    This feature article presents an overview of a study of several different aromatic-functionalized amphiphiles-fatty acid and phospholipid derivatives. These amphiphiles form organized assemblies when the fatty acids are spread as monolayers at the air-water interface or when the phospholipids are dispersed in aqueous solutions. For a wide range of aromatic chromophores--trans-stilbene derivatives and a series of vinylogues (1,4-diphenyl-1,3-butadiene and 1,6-diphenyl-1,3,5-hexatriene), diphenylacetylenes, and azobenzenes such as phenyl, biphenyl, and terphenyl derivatives and modified stilbenes (styryl thiophenes and styryl naphthalenes)--assembly formation is accompanied by formation of aggregates of the aromatic groups. Results of experimental studies and simulations indicate that in many cases the aromatics form a small, stable unit aggregate characterized by strong noncovalent edge-to-face interactions among adjacent aromatics. Although the unit aggregates exhibit characteristic spectral shifts and strong induced circular dichroism indicating a chiral pinwheel aggregate structure, they may be packed together in pure films or dispersions to form an extended glide or herringbone structure. Although the pinwheel unit aggregate and the extended glide or herringbone structure. Although the pinwheel unit aggregate and the extended glide structure is favored for the majority of aromatics studied, for certain aromatics (styrenes, styrylthiophenes, and {alpha}-styrylnaphthalenes) a translation layer, characterized by face-to-face noncovalent interactions, is preferred. The glide or herringbone aggregates are readily distinguished from the translation aggregates by different spectral signatures and different photochemical and photophysical behavior. Factors controlling the type of aggregate and hence extended structure formed from different aromatic functionalized aromatics include shape and steric factors and strength of the competing noncovalent edge-face and face

  3. Hetero- and Homoleptic Magnesium Triazenides

    Directory of Open Access Journals (Sweden)

    Denis Vinduš

    2017-05-01

    Full Text Available Using monoanionic triazenide ligands derived from biphenyl and m-terphenyl substituted triazenes Dmp(TphN3H (1a, (Me4Ter2N3H (1b or Dmp(MphN3H (1c (Dmp = 2,6-Mes2C6H3 with Mes = 2,4,6-Me3C6H2; Me4Ter = 2,6-(3,5-Me2C6H32C6H3; Mph = 2-MesC6H4; Tph = 2-TripC6H4 with Trip = 2,4,6-i-Pr3C6H2, several magnesium triazenides were synthesized. Heteroleptic complexes [Mg(N3Ar2I(OEt2] (Ar2 = Dmp/Tph (2a, (Me4Ter2 (2b were obtained from metalation of the corresponding triazenes with di-n-butylmagnesium followed by reaction with iodine in diethyl ether as the solvent in high yields. Replacing diethyl ether by n-heptane afforded trinuclear compounds [Mg3(N3Ar22I4] (3a, 3b in low yields in which a central MgI2 fragment is coordinated by two iodomagnesium triazenide moieties. Two unsolvated homoleptic magnesium compounds [Mg(N3Ar22] (4b, 4c were obtained from di-n-butylmagnesium and triazenes 1b or 1c in a 1:2 ratio. Depending on the nature of the substituents, the magnesium center either shows the expected tetrahedral or a rather unusual square planar coordination.

  4. Enhanced Catalysis Activity in a Coordinatively Unsaturated Cobalt-MOF Generated via Single-Crystal-to-Single-Crystal Dehydration.

    Science.gov (United States)

    Ren, Hai-Yun; Yao, Ru-Xin; Zhang, Xian-Ming

    2015-07-06

    Hydrothermal reaction of Co(NO3)2 and terphenyl-3,2",5",3'-tetracarboxyate (H4tpta) generated Co3(OH)2 chains based 3D coordination framework Co3(OH)2(tpta)(H2O)4 (1) that suffered from single-crystal-to-single-crystal dehydration by heating at 160 °C and was transformed into dehydrated Co3(OH)2(tpta) (1a). During the dehydration course, the local coordination environment of part of the Co atoms was transformed from saturated octahedron to coordinatively unsaturated tetrahedron. Heterogenous catalytic experiments on allylic oxidation of cyclohexene show that dehydrated 1a has 6 times enhanced catalytic activity than as-synthesized 1 by using tert-butyl hydroperoxide (t-BuOOH) as oxidant. The activation energy for the oxidation of cylcohexene with 1a catalyst was 67.3 kJ/mol, far below the value with 1 catalysts, which clearly suggested that coordinatively unsaturated Co(II) sites in 1a have played a significant role in decreasing the activation energy. It is interestingly found that heterogeneous catalytic oxidation of cyclohexene in 1a not only gives the higher conversion of 73.6% but also shows very high selectivity toward 2-cyclohexene-1-one (ca. 64.9%), as evidenced in high turnover numbers (ca. 161) based on the open Co(II) sites of 1a catalyst. Further experiments with a radical trap indicate a radical chain mechanism. This work demonstrates that creativity of coordinatively unsaturated metal sites in MOFs could significantly enhance heterogeneous catalytic activity and selectivity.

  5. Growth of polyphenyls via ion-molecule reactions: An experimental and theoretical mechanistic study

    Energy Technology Data Exchange (ETDEWEB)

    Aysina, Julia; Tosi, Paolo; Ascenzi, Daniela [Dipartimento di Fisica, Universita di Trento, Via Sommarive 14, I-38123 Povo, Trento (Italy); Maranzana, Andrea; Tonachini, Glauco [Dipartimento di Chimica, Universita di Torino, Corso Massimo D' Azeglio 48, I-10125 Torino (Italy)

    2013-05-28

    The reactivity of biphenylium cations C{sub 12}H{sub 9}{sup +} with benzene C{sub 6}H{sub 6} is investigated in a joint experimental and theoretical approach. Experiments are performed by using a triple quadruple mass spectrometer equipped with an atmospheric pressure chemical ion source to generate C{sub 12}H{sub 9}{sup +} via dissociative ionization of various isomers of the neutral precursor hydroxybiphenyl (C{sub 12}H{sub 10}O). C-C coupling reactions leading to hydrocarbon growth are observed. The most abundant ionic products are C{sub 18}H{sub 15}{sup +}, C{sub 18}H{sub 13}{sup +}, C{sub 17}H{sub 12}{sup +}, and C{sub 8}H{sub 7}{sup +}. The dependence of product ion yields on the kinetic energy of reagent ions, as well as further experiments performed using partial isotopic labelling of reagents, support the idea that the reaction proceeds via a long lived association product, presumably the covalently bound protonated terphenyl C{sub 18}H{sub 15}{sup +}. Its formation is found to be exothermic and barrierless and, therefore, might occur under the low pressure and temperature conditions typical of planetary atmospheres and the interstellar medium. Theoretical calculations have focussed on the channel leading to C{sub 8}H{sub 7}{sup +} plus C{sub 10}H{sub 8}, identifying, as the most probable fragments, the phenylethen-1-ylium cation and naphthalene, thus suggesting that the pathway leading to them might be of particular interest for the synthesis of polycyclic aromatic hydrocarbons. Both experiments and theory agree in finding this channel exoergic but hampered by small barriers of 2.7 and 3.7 kcal mol{sup -1} on the singlet potential energy surface.

  6. Electrochemical Reduction of Dissolved Oxygen in Alkaline, Solid Polymer Electrolyte Films.

    Science.gov (United States)

    Novitski, David; Kosakian, Aslan; Weissbach, Thomas; Secanell, Marc; Holdcroft, Steven

    2016-11-30

    Mass transport of oxygen through an ionomer contained within the cathode catalyst layer in an anion exchange membrane fuel cell is critical for a functioning fuel cell, yet is relatively unexplored. Moreover, because water is a reactant in the oxygen reduction reaction (ORR) in alkaline media, an adequate supply of water is required. In this work, ORR mass transport behavior is reported for methylated hexamethyl-p-terphenyl polymethylbenzimidazoles (HMT-PMBI), charge balanced by hydroxide ions (IEC from 2.1 to 2.5 mequiv/g), and commercial Fumatec FAA-3 membranes. Electrochemical mass transport parameters are determined by potential step chronoamperometry using a Pt microdisk solid-state electrochemical cell, in air at 60 °C, with relative humidity controlled between 70% and 98%. The oxygen diffusion coefficient (D bO2 ), oxygen concentration (c bO2 ), and oxygen permeability (D bO2 ·c bO2 ) were obtained by nonlinear curve fitting of the current transients using the Shoup-Szabo equation. Mass transport parameters are correlated to water content of the ionomer membrane. It is found that the oxygen diffusion coefficients decreased by 2 orders of magnitude upon reducing the water content of the ionomer membrane by lowering the relative humidity. The limitation of the Shoup-Szabo equation for extracting ORR mass transport parameters using thin ionomer films was evaluated by numerical modeling of the current transients, which revealed that a significant discrepancy (up to 29% under present conditions) was evident for highly hydrated membranes for which the oxygen diffusion coefficient was largest, and in which the oxygen depletion region reached the ionomer/gas interface during the chronoamperometric analysis.

  7. A visible-light-excited europium(III) complex-based luminescent probe for visualizing copper ions and hydrogen sulfide in living cells

    Science.gov (United States)

    Wang, Yiren; Wang, Huan; Yang, Mei; Yuan, Jingli; Wu, Jing

    2018-01-01

    Development of visible-light-excited lanthanide (III) complex-based luminescent probes is highly appealing due to their superiority of less damage to the living biosystems over the conventional UV-light-excited ones. In this work, a visible-light-excited europium (III) complex-based luminescent probe, BPED-BHHCT-Eu3+-BPT, has been designed and synthesized by conjugating the Cu2+-binding N,N-bis(2-pyridylmethyl)ethanediamine (BPED) to a tetradentate β-diketone ligand 4,4‧-bis(1″,1″,1″,2″,2″,3″,3″-heptafluoro-4″,6″-hexanedione-6″-yl)chlorosulfo-o-terphenyl (BHHCT) and coordinating with a coligand 2-(N,N-diethylanilin-4-yl)-4,6-bis(pyrazol-1-yl)-1,3,5-triazine) (BPT) for the time-gated luminescence detection of Cu2+ ions and hydrogen sulfide (H2S) in living cells. BPED-BHHCT-Eu3+-BPT exhibited a sharp excitation peak at 407 nm and a wide excitation window extending to beyond 460 nm. Upon its reaction with Cu2+ ions, the luminescence of BPED-BHHCT-Eu3+-BPT was efficiently quenched, which could be reversibly restored by the addition of H2S due to the strong affinity between Cu2+ ions and H2S. The "on-off-on" type luminescence behavior of BPED-BHHCT-Eu3+-BPT towards Cu2+ ions and H2S enabled the sensing of the two species with high sensitivity and selectivity. The performances of BPED-BHHCT-Eu3+-BPT for visualizing intracellular Cu2+ ions and H2S were investigated, and the results have demonstrated the practical applicability of the probe for molecular imaging of cells.

  8. Fish bioconcentration studies with column-generated analyte concentrations of highly hydrophobic organic chemicals.

    Science.gov (United States)

    Schlechtriem, Christian; Böhm, Leonard; Bebon, Rebecca; Bruckert, Hans-Jörg; Düring, Rolf-Alexander

    2017-04-01

    The performance of aqueous exposure bioconcentration fish tests according to Organisation for Economic Co-operation and Development (OECD) guideline 305 requires the possibility of preparing stable aqueous concentrations of the test substances. For highly hydrophobic organic chemicals (HOCs; octanol-water partition coefficient [log K OW ] > 5), testing via aqueous exposure may become increasingly difficult. A solid-phase desorption dosing system was developed to generate stable concentrations of HOCs without using solubilizing agents. The system was tested with hexachlorobenzene (HCB), o-terphenyl (oTP), polychlorinated biphenyl (PCB) 153, and dibenz[a,h]anthracene (DBA) (log K OW 5.5-7.8) in 2 flow-through fish tests with rainbow trout (Oncorhynchus mykiss). The analysis of the test media applied during the bioconcentration factor (BCF) studies showed that stable analyte concentrations of the 4 HOCs were maintained in the test system over an uptake period of 8 wk. Bioconcentration factors (L kg -1 wet wt) were estimated for HCB (BCF 35 589), oTP (BCF 12 040), and PCB 153 (BCF 18 539) based on total water concentrations. No bioconcentration could be determined for DBA, probably because of the rapid metabolism of the test item. The solid-phase desorption dosing system is suitable to provide stable aqueous concentrations of HOCs required to determine the bioconcentration in fish and represents a viable alternative to the use of solubilizing agents for the preparation of test solutions. Environ Toxicol Chem 2017;36:906-916. © 2016 The Authors. Environmental Toxicology and Chemistry Published by Wiley Periodicals, Inc. on behalf of SETAC. © 2016 The Authors. Environmental Toxicology and Chemistry Published by Wiley Periodicals, Inc. on behalf of SETAC.

  9. Properties of scintillator solutes

    Energy Technology Data Exchange (ETDEWEB)

    Fluornoy, J.M.

    1998-06-01

    This special report summarizes measurements of the spectroscopic and other properties of the solutes that were used in the preparation of several new liquid scintillators developed at EG and G/Energy Measurements/Santa Barbara Operations (the precursor to Bechtel Nevada/Special Technologies Laboratory) on the radiation-to-light converter program. The data on the individual compounds are presented in a form similar to that used by Prof. Isadore Berlman in his classic handbook of fluorescence spectra. The temporal properties and relative efficiencies of the new scintillators are presented in Table 1, and the efficiencies as a function of wavelength are presented graphically in Figure 1. In addition, there is a descriptive glossary of the abbreviations used herein. Figure 2 illustrates the basic structures of some of the compounds and of the four solvents reported in this summary. The emission spectra generally exhibit more structure than the absorption spectra, with the result that the peak emission wavelength for a given compound may lie several nm away from the wavelength, {lambda}{sub avg}, at the geometric center of the emission spectrum. Therefore, the author has chosen to list absorption peaks, {lambda}{sub max}, and emission {lambda}{sub avg} values in Figures 3--30, as being most illustrative of the differences between the compounds. The compounds, BHTP, BTPB, ADBT, and DPTPB were all developed on this program. P-terphenyl, PBD, and TPB are commercially available blue emitters. C-480 and the other longer-wavelength emitters are laser dyes available commercially from Exciton Corporation. 1 ref., 30 figs.

  10. Buckling Analysis for the Shape of the Thin-tube Support of Radioisotope Thermoelectric Generator to investigate structure integrity

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jong Han; Son, Kwang Jae; Hong, Jintae; Kim, Jong Bum [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-10-15

    Radiation detection using scintillator light produced in materials is one of the oldest and most useful techniques for the detection of a variety of radiations. A detector using plastic scintillators is well known to have an easy operation because it consists of a chemically stable material. In general, a plastic scintillator using a polymer such as polymethylmethacrylate (PMMA), polyvinyltoluene (PVT) or polystyrene (PS) is added to an organic scintillator. As an organic scintillator, the first solute is p-terphenyl or 2.5-diphenyloxazole (PPO), and the second solute is 1,4-bis [5-phenyl-2-oxazol] benzene (POPOP). A method for preparing a plastic scintillator is a mixture of a polymer and organic scintillators used for thermal polymerization. In this study, we prepared a plastic scintillator whose manufacturing process is simple and can be freely shaped. A thin plate of the plastic scintillator was manufactured using epoxy resin as a polymer. The optimal mixture ratio to prepare the plastic scintillator was derived from the above results. Using the derived results, we made the large-area plastic scintillator which can quickly measure the contamination site and evaluated characteristics of the large-area plastic scintillator in the laboratory. A thin plate of a plastic scintillator with a simple preparation process can be freely shaped using epoxy resin and organic scintillators such as PPO and POPOP. PPO emits scintillation of light in the ultraviolet range, and POPOP is a wave shifter for moving the wavelength responsible for the PMT. The mixture ratio of PPO and POPOP was determined using their emission spectra. The optimal weight percentage of PPO and POPOP in an organic scintillator was determined to be 0.2 wt%:0.01 wt%. Based on the above results, the large-area plastic scintillator of the window size of a typical pancake-type surface contamination counter was prepared. We want to evaluate the characteristics of the large-area plastic scintillator. However

  11. SOLVENT PURIFICATION AND FLUOR SELECTION FOR GADOLINIUM-LOADED LIQUID SCINTILLATORS

    Energy Technology Data Exchange (ETDEWEB)

    Kesete, T.; Storm, A.; Hahn, R. L.; Yeh, M.; Seleem, S.

    2007-01-01

    The last decade has seen huge progress in the study of neutrinos, elementary sub-atomic particles. Continued growth in the fi eld of neutrino research depends strongly on the calculation of the neutrino mixing angle θ13, a fundamental neutrino parameter that is needed as an indicative guideline for proposed next-generation neutrino experiments. Experiments involving reactor antineutrinos are favored for the calculation of θ13 because their derivation equation for θ13 is relatively simple and unambiguous. A Gd-loaded liquid scintillator (Gd-LS) is the centerpiece of the detector and it consists of ~99% aromatic solvent, ~0.1% Gd, and < 1% fl uors. Key required characteristics of the Gd-LS are long-term chemical stability, high optical transparency, and high photon production by the scintillator. This summer’s research focused on two important aspects of the detector: (1) purifi cation of two selected scintillation solvents, 1, 2, 4-trimethylbenzene (PC) and linear alkyl benzene (LAB), to improve the optical transparency and long-term chemical stability of the Gd-LS, and (2) investigation of the added fl uors to optimize the photon production. Vacuum distillation and column separation were used to purify PC and LAB, respectively. Purifi cation was monitored using UV-visible absorption spectra and verifi ed in terms of decreased solvent absorption at 430nm. Absorption in PC at 430nm decreased by a factor slightly >10 while the absorption in LAB was lowered by a factor of ~5. Photon production for every possible combination of two solvents, four primary shifters, and two secondary shifters was determined by measuring the Compton-Scattering excitation induced by an external Cs-137 gamma source (Eγ ~ 662-keV). The ideal shifter concentration was identifi ed by measuring the photon production as a function of shifter quantity in a series of samples. Results indicate that 6g/L p-terphenyl with 150mg/L 1,4-Bis(2-methylstyryl)-benzene (bis-MSB) produces the maximum

  12. Highly Stable Zr(IV)-Based Metal-Organic Frameworks for the Detection and Removal of Antibiotics and Organic Explosives in Water.

    Science.gov (United States)

    Wang, Bin; Lv, Xiu-Liang; Feng, Dawei; Xie, Lin-Hua; Zhang, Jian; Li, Ming; Xie, Yabo; Li, Jian-Rong; Zhou, Hong-Cai

    2016-05-18

    Antibiotics and organic explosives are among the main organic pollutants in wastewater; their detection and removal are quite important but challenging. As a new class of porous materials, metal-organic frameworks (MOFs) are considered as a promising platform for the sensing and adsorption applications. In this work, guided by a topological design approach, two stable isostructural Zr(IV)-based MOFs, Zr6O4(OH)8(H2O)4(CTTA)8/3 (BUT-12, H3CTTA = 5'-(4-carboxyphenyl)-2',4',6'-trimethyl-[1,1':3',1″-terphenyl]-4,4″-dicarboxylic acid) and Zr6O4(OH)8(H2O)4(TTNA)8/3 (BUT-13, H3TTNA = 6,6',6″-(2,4,6-trimethylbenzene-1,3,5-triyl)tris(2-naphthoic acid)) with the the-a topological structure constructed by D4h 8-connected Zr6 clusters and D3h 3-connected linkers were designed and synthesized. The two MOFs are highly porous with the Brunauer-Emmett-Teller surface area of 3387 and 3948 m(2) g(-1), respectively. Particularly, BUT-13 features one of the most porous water-stable MOFs reported so far. Interestingly, these MOFs represent excellent fluorescent properties, which can be efficiently quenched by trace amounts of nitrofurazone (NZF) and nitrofurantoin (NFT) antibiotics as well as 2,4,6-trinitrophenol (TNP) and 4-nitrophenol (4-NP) organic explosives in water solution. They are responsive to NZF and TNP at parts per billion (ppb) levels, which are among the best performing luminescent MOF-based sensing materials. Simultaneously, both MOFs also display high adsorption abilities toward these organic molecules. It was demonstrated that the adsorption plays an important role in the preconcentration of analytes, which can further increase the fluorescent quenching efficiency. These results indicate that BUT-12 and -13 are favorable materials for the simultaneous selective detection and removal of specific antibiotics and organic explosives from water, being potentially useful in monitoring water quality and treating wastewater.

  13. Dynamical transition in molecular glasses and proteins observed by spin relaxation of nitroxide spin probes and labels

    Science.gov (United States)

    Golysheva, Elena A.; Shevelev, Georgiy Yu.; Dzuba, Sergei A.

    2017-08-01

    In glassy substances and biological media, dynamical transitions are observed in neutron scattering that manifests itself as deviations of the translational mean-squared displacement, , of hydrogen atoms from harmonic dynamics. In biological media, the deviation occurs at two temperature intervals, at ˜100-150 K and at ˜170-230 K, and it is attributed to the motion of methyl groups in the former case and to the transition from harmonic to anharmonic or diffusive motions in the latter case. In this work, electron spin echo (ESE) spectroscopy—a pulsed version of electron paramagnetic resonance—is applied to study the spin relaxation of nitroxide spin probes and labels introduced in molecular glass former o-terphenyl and in protein lysozyme. The anisotropic contribution to the rate of the two-pulse ESE decay, ΔW, is induced by spin relaxation appearing because of restricted orientational stochastic molecular motion; it is proportional to τc, where is the mean-squared angle of reorientation of the nitroxide molecule around the equilibrium position and τc is the correlation time of reorientation. The ESE time window allows us to study motions with τc τc temperature dependence shows a transition near 240 K, which is in agreement with the literature data on . For spin probes of essentially different size, the obtained data were found to be close, which evidences that motion is cooperative, involving a nanocluster of several neighboring molecules. For the dry lysozyme, the τc values below 260 K were found to linearly depend on the temperature in the same way as it was observed in neutron scattering for . As spin relaxation is influenced only by stochastic motion, the harmonic motions seen in ESE must be overdamped. In the hydrated lysozyme, ESE data show transitions near 130 K for all nitroxides, near 160 K for the probe located in the hydration layer, and near 180 K for the label in the protein interior. For this system, the two latter transitions are not

  14. Thermic decomposition of biphenyl; Decomposition thermique du biphenyle

    Energy Technology Data Exchange (ETDEWEB)

    Lutz, M. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1966-03-01

    Liquid and vapour phase pyrolysis of very pure biphenyl obtained by methods described in the text was carried out at 400 C in sealed ampoules, the fraction transformed being always less than 0.1 per cent. The main products were hydrogen, benzene, terphenyls, and a deposit of polyphenyls strongly adhering to the walls. Small quantities of the lower aliphatic hydrocarbons were also found. The variation of the yields of these products with a) the pyrolysis time, b) the state (gas or liquid) of the biphenyl, and c) the pressure of the vapour was measured. Varying the area and nature of the walls showed that in the absence of a liquid phase, the pyrolytic decomposition takes place in the adsorbed layer, and that metallic walls promote the reaction more actively than do those of glass (pyrex or silica). A mechanism is proposed to explain the results pertaining to this decomposition in the adsorbed phase. The adsorption seems to obey a Langmuir isotherm, and the chemical act which determines the overall rate of decomposition is unimolecular. (author) [French] Du biphenyle tres pur, dont la purification est decrite, est pyrolyse a 400 C en phase vapeur et en phase liquide dans des ampoules scellees sous vide, a des taux de decomposition n'ayant jamais depasse 0,1 pour cent. Les produits provenant de la pyrolyse sont essentiellement: l' hydrogene, le benzene, les therphenyles, et un depot de polyphenyles adherant fortement aux parois. En plus il se forme de faibles quantites d'hydrocarbures aliphatiques gazeux. On indique la variation des rendements des differents produits avec la duree de pyrolyse, l'etat gazeux ou liquide du biphenyle, et la pression de la vapeur. Variant la superficie et la nature des parois, on montre qu'en absence de liquide la pyrolyse se fait en phase adsorbee. La pyrolyse est plus active au contact de parois metalliques que de celles de verres (pyrex ou silice). A partir des resultats experimentaux un mecanisme de

  15. Characterization of conducting polymer films grown via surface polymerization by ion-assisted deposition

    Science.gov (United States)

    Tepavcevic, Sanja

    2006-04-01

    Optimization of photonic and electronic devices based on conductive polymers, such as polythiophene and polyphenyl, requires the development of processing methods that can control both film chemistry and morphology on the nanoscale. One such method is explored in this thesis: surface polymerization by ion-assisted deposition (SPIAD). Polythiophene and polyphenyl thin films are grown on a silicon surface by SPIAD which uses hyperthermal, mass-selected thiophene cations coincident with alpha-thermal beam of aterthiophene (3T) or p-terphenyl (3P) neutrals. Mass spectrometry and x-ray photoelectron spectroscopy are used to verify polymerization of both 3T and 3P. The optimal conditions for the most efficient polymerization reaction and film growth are found by varying ion/neutral ratio and ion energy. The electronic structures of these films are probed by ultraviolet photoelectron spectroscopy (UPS) and polarized near-edge x-ray absorption fine structure spectroscopy (NEXAFS). The conducting polymer films formed by SPIAD display new valence band features resulting from a reduction in both their band gap and barrier to hole injection. These changes in film electronic structure result from an increase in the electron conjugation length and other changes in film structure induced by SPIAD. Scanning electron microscopy and x-ray diffraction are used to demonstrate that SPIAD can control the overall polythiophene and polyphenyl film morphology through the mediation of adsorption, diffusion, sublimation (desorption), and other thermal film growth events by ion-induced processes including polymerization, sputtering, bond breakage, and energetic mixing. Predicting the electronic properties, growth mechanism and morphology of the SPIAD films should be possible through computer simulations of the controlling phenomenon. Study with first principles density functional theory-molecular dynamics (DFT-MD) simulations indicates that polymerization and fragmentation of ions and

  16. Two new Co(II)-MOFs based on polymeric chain building units: Crystal structures, and magnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Han, Min-Le [College of Materials & Chemical Engineering, Collaborative Innovation Center for Microgrid of New Energy of Hubei Province, China Three Gorges University, Yichang 443002 (China); Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, College of Chemistry & Materials Science, Northwest University, Xi’an 710069 (China); Wu, Ya-Pan; Zhao, Jun [College of Materials & Chemical Engineering, Collaborative Innovation Center for Microgrid of New Energy of Hubei Province, China Three Gorges University, Yichang 443002 (China); Li, Dong-Sheng, E-mail: lidongsheng1@126.com [College of Materials & Chemical Engineering, Collaborative Innovation Center for Microgrid of New Energy of Hubei Province, China Three Gorges University, Yichang 443002 (China); Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, College of Chemistry & Materials Science, Northwest University, Xi’an 710069 (China); Wang, Yao-Yu [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, College of Chemistry & Materials Science, Northwest University, Xi’an 710069 (China)

    2015-10-15

    Two new Co(II) metal-organic frameworks, namely [Co{sub 2}(bpm)(H{sub 2}O){sub 3}(L)]{sub n} (1) and ([Co(bpe)(H{sub 2}O)(H{sub 2}L)]·(bpe){sub 0.5}·(H{sub 2}O)){sub n} (2), (H{sub 4}L=1,1′:2′,1″-terphenyl-3,3″,4′,5′-tetracarboxylic acid, bpm=bis(4-pyridyl)amine, bpe=1,2-bis(4-pyridyl)ethene), have been obtained under hydrothermal conditions. Both complexes 1 and 2 have been characterized by elemental analysis, IR spectra, single-crystal X-ray diffraction, powder X-ray diffraction (PXRD), and thermogravimetric analysis (TGA). Complexes 1 and 2 consist of 1D Co(II) chains bridging by carboxylate groups in syn-anti fashion. 1 shows a novel 3D tri-nodal (4,6,10)-connected net with a (3.4{sup 3}.5{sup 2}){sub 2}(3{sup 2}.4{sup 14}.5{sup 12}.6{sup 12}.7{sup 4}.8)(3{sup 2}.4{sup 2}.5{sup 5}.6{sup 4}.7{sup 2}) topology. While 2 exhibits a 2D sql layer. Magnetic susceptibility measurements indicate that both 1 and 2 show weak antiferromagnetic interactions between the adjacent Co(II) ions in 300–8 K for 1 and 300–16 K for 2, respectively, and then 2 also displays ferromagnetic coupling at lower temperatures. - Graphical abstract: Two Co(II) coordination polymers with similar metal chain bridging by carboxylates in syn-anti fashion have been synthesized. Both 1 and 2 show weak antiferromagnetic interactions in high temperature, and then 2 also displays ferromagnetic coupling at lower temperatures. - Highlights: • Two Co(II) coordination polymers with similar metal chain bridging by carboxylates. • A novel 3D (4,6,10)-connected net and a 2D sql layers. • A antiferromagnetic coupling at high temperature for 1 and 2. • A ferromagnetic coupling at lower temperature for 2.

  17. What Is a Simple Liquid?

    Directory of Open Access Journals (Sweden)

    Trond S. Ingebrigtsen

    2012-03-01

    Full Text Available This paper is an attempt to identify the real essence of simplicity of liquids in John Locke’s understanding of the term. Simple liquids are traditionally defined as many-body systems of classical particles interacting via radially symmetric pair potentials. We suggest that a simple liquid should be defined instead by the property of having strong correlations between virial and potential-energy equilibrium fluctuations in the NVT ensemble. There is considerable overlap between the two definitions, but also some notable differences. For instance, in the new definition simplicity is not a direct property of the intermolecular potential because a liquid is usually only strongly correlating in part of its phase diagram. Moreover, not all simple liquids are atomic (i.e., with radially symmetric pair potentials and not all atomic liquids are simple. The main part of the paper motivates the new definition of liquid simplicity by presenting evidence that a liquid is strongly correlating if and only if its intermolecular interactions may be ignored beyond the first coordination shell (FCS. This is demonstrated by NVT simulations of the structure and dynamics of several atomic and three molecular model liquids with a shifted-forces cutoff placed at the first minimum of the radial distribution function. The liquids studied are inverse power-law systems (r^{-n} pair potentials with n=18,6,4, Lennard-Jones (LJ models (the standard LJ model, two generalized Kob-Andersen binary LJ mixtures, and the Wahnstrom binary LJ mixture, the Buckingham model, the Dzugutov model, the LJ Gaussian model, the Gaussian core model, the Hansen-McDonald molten salt model, the Lewis-Wahnstrom ortho-terphenyl model, the asymmetric dumbbell model, and the single-point charge water model. The final part of the paper summarizes properties of strongly correlating liquids, emphasizing that these are simpler than liquids in general. Simple liquids, as defined here, may be

  18. Search for Heavy Majorana Neutrinos in Pp Collisions at √S = 8 Tev with the CMS Detector & Photodetector and Calorimeter R&D for Particle Colliders

    Science.gov (United States)

    Tiras, Emrah

    the experiment. The second section reports characterization results of two types of PMTs in a novel operation mode for Secondary Emission (SE) Ionization Calorimetry, which is a novel technique to measure electromagnetic shower particles in extreme radiation environments. The third section presents the test results of novel scintillating materials for CMS experiment in specific and future particle accelerators in general. These materials are Polyethylene Naphthalate (PEN), Polyethylene Terephthalate (PET), high efficiency mirror (HEM) and quartz plates with various organic and inorganic coating materials such as p-Terphenyl (pTp), Anthracene and Gallium-doped Zinc Oxide (ZnO:Ga). We have investigated them for radiation hardness, light yield, timing characteristics, and scintillation and transmission properties.

  19. What Is a Simple Liquid?

    Science.gov (United States)

    Ingebrigtsen, Trond S.; Schrøder, Thomas B.; Dyre, Jeppe C.

    2012-01-01

    This paper is an attempt to identify the real essence of simplicity of liquids in John Locke’s understanding of the term. Simple liquids are traditionally defined as many-body systems of classical particles interacting via radially symmetric pair potentials. We suggest that a simple liquid should be defined instead by the property of having strong correlations between virial and potential-energy equilibrium fluctuations in the NVT ensemble. There is considerable overlap between the two definitions, but also some notable differences. For instance, in the new definition simplicity is not a direct property of the intermolecular potential because a liquid is usually only strongly correlating in part of its phase diagram. Moreover, not all simple liquids are atomic (i.e., with radially symmetric pair potentials) and not all atomic liquids are simple. The main part of the paper motivates the new definition of liquid simplicity by presenting evidence that a liquid is strongly correlating if and only if its intermolecular interactions may be ignored beyond the first coordination shell (FCS). This is demonstrated by NVT simulations of the structure and dynamics of several atomic and three molecular model liquids with a shifted-forces cutoff placed at the first minimum of the radial distribution function. The liquids studied are inverse power-law systems (r-n pair potentials with n=18,6,4), Lennard-Jones (LJ) models (the standard LJ model, two generalized Kob-Andersen binary LJ mixtures, and the Wahnstrom binary LJ mixture), the Buckingham model, the Dzugutov model, the LJ Gaussian model, the Gaussian core model, the Hansen-McDonald molten salt model, the Lewis-Wahnstrom ortho-terphenyl model, the asymmetric dumbbell model, and the single-point charge water model. The final part of the paper summarizes properties of strongly correlating liquids, emphasizing that these are simpler than liquids in general. Simple liquids, as defined here, may be characterized in three quite

  20. Coupling molecular catalysts with nanostructured surfaces for efficient solar fuel production

    Science.gov (United States)

    Jin, Tong

    Solar fuel generation via carbon dioxide (CO2) reduction is a promising approach to meet the increasing global demand for energy and to minimize the impact of energy consumption on climate change. However, CO2 is thermodynamically stable; its activation often requires the use of appropriate catalysts. In particular, molecular catalysts with well-defined structures and tunability have shown excellent activity in photochemical CO2 reduction. These homogenous catalysts, however, suffer from poor stability under photochemical conditions and difficulty in recycling from the reaction media. Heterogenized molecular catalysts, particularly those prepared by coupling molecular catalysts with solid-state surfaces, have attracted more attention in recent years as potential solutions to address the issues associated with molecular catalysts. In this work, solar CO2 reduction is investigated using systems coupling molecular catalysts with robust nanostructured surfaces. In Chapter 2, heterogenization of macrocyclic cobalt(III) and nickel (II) complexes on mesoporous silica surface was achieved by different methods. Direct ligand derivatization significantly lowered the catalytic activity of Co(III) complex, while grafting the Co(III) complex onto silica surface through Si-O-Co linkage resulted in hybrid catalysts with excellent activity in CO2 reduction in the presence of p-terphenyl as a molecular photosensitizer. An interesting loading effect was observed, in which the optimal activity was achieved at a medium Co(III) surface density. Heterogenization of the Ni(II) complex on silica surface has also been implemented, the poor photocatalytic activity of the hybrid catalyst can be attributed to the intrinsic nature of the homogeneous analogue. This study highlighted the importance of appropriate linking strategies in preparing functional heterogenized molecular catalysts. Coupling molecular complexes with light-harvesting surfaces could avoid the use of expensive molecular

  1. Design of the detector to observe the energetic charged particles: a part of the solar X-ray spectrophotometer ChemiX onboard Interhelio-Probe mission

    Science.gov (United States)

    Dudnik, Oleksiy; Sylwester, Janusz; Kowalinski, Miroslaw; Bakala, Jaroslaw; Siarkowski, Marek; Evgen Kurbatov, mgr..

    2016-07-01

    -layer detector stack: first two layers consist of silicon detectors; the third one is based on the p-terphenyl scintillation detector coupled with pixelated silicon photomultiplier. Coincidence logic allows collecting systematic data on particle variety and their energy with 1 and/or 10 s time resolutions. Digital processing unit is constructed based on FPGA Actel ProAsic M1A3PE1500, and contains each event processing logic, forms telemetry data and housekeeping frames, communicates with ChemiX digital processing unit and executes received telecommands. In order to increase the reliability and time resource of the BPM its digital processing unit and secondary power supply unit has backup sets. Switching between backup sets is commanded by externally orders. The BPM is capable to sort out in situ abundances of individual particle constituents from electrons up to oxygen nuclei. 1. O.V.Dudnik, E.V.Kurbatov, V.O.Tarasov, L.A.Andryushenko, I.L.Zajtsevsky, J.Sylwester, J.Bąkala, M.Kowaliński. Background particle detector for the solar X-ray photometer ChemiX of space mission "Interhelioprobe": an adjustment of breadboard model modules (in Russian) / ISSN 1561-8889: Kosmichna Nauka I Tekhnologiya, 2015, Vol.21, No.2, P.3-14. 2. O.V.Dudnik, E.V.Kurbatov, J.Sylwester, M.Siarkowski, P.Podgórski, M.Kowaliński. Background Particle Monitor - a part of the solar X-ray spectrophotometer ChemiX: principles of the operation and construction / in: Abstracts of 15th Ukrainian conference on space research, Odesa, Ukraine, August 24-28, 2015, P.80, doi:10.13140/RG.2.1.2284.2649. 3. O.V.Dudnik, E.V.Kurbatov, M.Kowaliński, M.Siarkowski, P.Podgórski, J.Sylwester. Operational features of Background Particle Monitor, a vital part of the solar X-ray spectrophotometer ChemiX / in: Abstract book of the Conference "Progress on EUV&X-ray spectroscopy and imaging II", Wroclaw, Poland, November 17 19, 2015, P.9, doi:10.13140/RG.2.1.1184.3604.