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Sample records for 1-furfuryl pyrrole characterization

  1. Characterization of poly pyrrole/montmorillonite electro polymerised onto Pt

    In this study films of polypyrrole/montmorillonite (PPy/MT) were electropolymerized on platinum in order to evaluate the performance of this technique in the preparation of nanocomposite materials and to determine the thermal properties and conductivity of the composites. The films were synthesized from a solution containing pyrrole, dodecylbenzene sulfonate, acid and two types of clays: montmorillonite-Na + (MT-Na) and montmorillonite-30B (MT-M). The characterization of the films we have used FT-IR, TEM, XRD, TGA, DSC and resistivity measurement by the four-point van der Pauw method. The study showed that the adopted method of exfoliation and the electropolymerization method used, allows obtaining nanocomposite materials. Analyses of FT-IR, TEM and XRD show that the clays are exfoliated in the polymer matrix. Thermal analysis of the films indicates that the addition of clay reflects an enhancement in the thermal properties of the matrix of PPy, but decreases the conductivity of the same. (author)

  2. Synthesis, Characterization and Biological Study of Novel Pyrrole Derivatives

    Rakesh R. Mishra

    2012-07-01

    Full Text Available A facile condensation of aromatic aldehydes with 2-(5-(phenoxymethyl-2-thioxo-1,3,4-oxadiazol-3(2H-ylaceto hydrazide (1 was give the corresponding N’-aryl-2-(5-(phenoxymethyl-2-thioxo-1,3,4-oxadiazol-3(2H-ylacetohydrazide (2a-e in good yield. Cyclo condensation of compounds (2a-e with maleic anhydride yields 2-aryl-5-oxo-1-(2-(5-(phenoxymethyl-2-thioxo-1,3,4-oxadiazol-3(2H-ylacetamido-2,5-dihydro-1H-pyrrole-3-carboxylic acid (3a-e. The structures of these compounds were established on the basis of analytical and spectral data. All the newly synthesized compounds were evaluated for their antibacterial and antifungal activities.

  3. Synthesis and Physical Characterization of Carbon Nano tubes Coated by Conducting Poly pyrrole

    This study describes the preparation of poly pyrrole multi walled carbon nano tube (PPy/ MWNT) composites by in situ chemical oxidative polymerization. Various ratios of functionalized MWNTs are dispersed in the water, and PPy are then synthesized via in-situ chemical oxidative polymerization on the surface of the carbon nano tubes. The morphology of the resulting complex nano tubes (MWNT-PPY) was characterized by scanning electron microscopy (SEM). The conductivity of each composite showed a maximum in the temperature scale of 120- 160 degree Celsius and then decreased dramatically with the increase of temperature. (author)

  4. -pyrrole substituted porphyrin-pyrene dyads using vinylene spacer: Synthesis, characterization and photophysical properties

    P Silviya Reeta; Ravi Kumar Kanaparthi; L Giribabu

    2013-03-01

    We have designed and synthesized donor-acceptor conjugates having donor pyrene at the pyrrole- position of either free-base porphyrin or Zn(II) porphyrin using vinylene spacer. Both the dyads have been completely characterized by elemental analysis,MALDI-MS, UV-Vis., and fluorescence (steady state and timeresolved) spectroscopies as well as cyclic voltammetry. The absorption maxima of both dyads are red-shifted by 8-12 nm. The ground state properties showed that there exist minimum - interaction between the aromatic subunits of these D-A systems. Quenched emission was observed in both the dyads when excited at 290 nm. The quenched emission explained in terms of intramolecular excitation energy transfer competes with the photo-induced electron transfer reaction in these D-A system.

  5. Synthesis, characterization, molecular docking and biological studies of self assembled transition metal dithiocarbamates of substituted pyrrole-2-carboxaldehyde.

    Nami, Shahab A A; Ullah, Irfan; Alam, Mahboob; Lee, Dong-Ung; Sarikavakli, Nursabah

    2016-07-01

    A series of self assembled 3d transition metal dithiocarbamate, M(pdtc) [where M=Mn(II), Fe(II), Co(II), Ni(II) and Cu(II)] have been synthesized and spectroscopically characterized. The bidentate dithiocarbamate ligand Na2pdtc (Disodium-1,4-phenyldiaminobis (pyrrole-1-sulfino)dithioate) was prepared by insertion reaction of carbondisulfide with Schiff base, N,N'-bis-(1H-pyrrol-2-ylmethylene)-benzene-1,4-diamine (L1) in basic medium. The simple substitution reaction between the metal halide and Na2pdtc yielded the title complexes in moderate yields. However, the in situ procedure gives high yield with the formation of single product as evident by TLC. Elemental analysis, IR, (1)H and (13)C NMR spectra, UV-vis., magnetic susceptibility and conductance measurements were done to characterize the complexes, M(pdtc). All the evidences suggest that the complexes have tetrahedral geometry excepting Cu(II) which is found to be square planar. A symmetrical bidentate coordination of the dithiocarbamato moiety has been observed in all the complexes. The conductivity data show that the complexes are non-electrolyte in nature. The anti-oxidant activity of the ligand, Na2pdtc and its transition metal complexes, M(pdtc) have been carried out using DPPH and Cu(pdtc) was found to be most effective. The anti-microbial activity of the Na2pdtc and M(pdtc) complexes have been carried out and on this basis the molecular docking study of the most effective complex, Cu(pdtc) has also been reported. PMID:27197060

  6. Electrochemical synthesis of Poly[3, 4-Propylenedioxythiophene-co-N-Phenylsulfonyl Pyrrole]: Morphological, electrochemical and spectroscopic characterization

    2011-06-01

    Full Text Available Electroactive random copolymers of 3,4-Propylenedioxythiophene (ProDOT and N-Phenylsulfonyl Pyrrole (PSP were electrochemically synthesized on single carbon fiber microelectrode (SCFME by cyclic voltammetry (CV. Fourier Transform Infrared-Attenuated Total Reflectance (FTIR-ATR measurements indicate the inclusion of PSP into the copolymer structure. The influence of feed ratios on the copolymers was studied by CV and electrochemical impedance spectroscopy (EIS and equivalent circuit modelling (ECM. The morphologies and film thicknesses of copolymers were characterized by scanning electron microscopy (SEM and atomic force microscopy (AFM. The results have shown that the principal changes in morphology, conductivity, porous nature and thickness of Poly(ProDOT-co-PSP film depend on the concentration of PSP. The strong electron-withdrawing sulfonyl group substitution on PSP significantly inhibited electrochemical copolymerization. Semicircular characteristics at Nyquist plots reflected an increasing trend with the increase of PSP concentration in the feed at high frequency. The semicircular characteristic of the copolymer film is useful for the bioelectrochemical sensor applications.

  7. Characterization of poly pyrrole/montmorillonite electro polymerised onto Pt; Caracterizacao de filmes PPy/montmorilonita eletropolimerizados sobre Pt

    Castagno, K.R.L., E-mail: katiarlc@pelotas.ifsul.edu.b [Instituto Federal Sul-rio-grandense (IFSul), RS (Brazil). Dept. de Quimica; Azambuja, D.S.; Dalmoro, V.; Mauller, R.S. [Universidade Federal do Rio Grande do Sul (UFRGS), Pelotas, RS (Brazil). Inst. de Quimica

    2010-07-01

    In this study films of polypyrrole/montmorillonite (PPy/MT) were electropolymerized on platinum in order to evaluate the performance of this technique in the preparation of nanocomposite materials and to determine the thermal properties and conductivity of the composites. The films were synthesized from a solution containing pyrrole, dodecylbenzene sulfonate, acid and two types of clays: montmorillonite-Na + (MT-Na) and montmorillonite-30B (MT-M). The characterization of the films we have used FT-IR, TEM, XRD, TGA, DSC and resistivity measurement by the four-point van der Pauw method. The study showed that the adopted method of exfoliation and the electropolymerization method used, allows obtaining nanocomposite materials. Analyses of FT-IR, TEM and XRD show that the clays are exfoliated in the polymer matrix. Thermal analysis of the films indicates that the addition of clay reflects an enhancement in the thermal properties of the matrix of PPy, but decreases the conductivity of the same. (author)

  8. Synthesis, characterization and anticancer studies of new steroidal oxadiazole, pyrrole and pyrazole derivatives

    Shamsuzzaman

    2015-07-01

    Full Text Available In the present study steroidal derivatives, 3β-[5′-mercapto-1′,3′,4′-oxadiazole-2-yl]methoxy cholest-5-ene 2, 3β-[2′,5′-dimethylpyrrole-1-yl]aminocarbonylmethoxycholest-5-ene 3 and 3β-[3′,5′-dimethyl pyrazole-1-yl]carbonylmethoxycholest-5-ene 4 have been synthesized from cholest-5-en-3β-O-acetyl hydrazide 1 using CS2/KOH, acetonyl acetone and acetyl acetone, respectively as reagents and are characterized by IR, 1H NMR,13C NMR, MS and elemental analysis. Compounds 2–4 were also evaluated for anticancer activity against human leukemia cell line (HL-60 by MTT assay and compound 4 displayed the promising behavior by showing better anticancer activity.

  9. The Oxidation of Pyrrole.

    Howard, James K; Rihak, Kieran J; Bissember, Alex C; Smith, Jason A

    2016-01-01

    The dearomatization of heterocycles has been a powerful means for producing functional molecules in synthesis. In the case of pyrroles, reductive methods (such as the Birch reduction) have been most widely exploited, while oxidative methods are generally dismissed as too difficult or unpredictable to be useful. However, since the early twentieth century considerable research has been carried out on the controlled oxidation of pyrroles to give highly functionalized products, using a variety of oxidants. This review presents a summary of all work up until the present day in the area of pyrrole oxidation, looking at the use of peroxide, singlet oxygen, hypervalent iodine reagents, a range or organic and inorganic oxidants, and electrochemical approaches. It also offers some perspective on the potential future role of pyrrole oxidation in synthesis. PMID:26294175

  10. Flexible supercapacitor based on electrochemically synthesized pyrrole formyl pyrrole copolymer coated on carbon microfibers

    Gholami, Mehrdad; Moozarm Nia, Pooria; Narimani, Leila; Sokhakian, Mehran; Alias, Yatimah

    2016-08-01

    The main objective of this work is to prepare a flexible supercapacitor using electrochemically synthesized pyrrole formyl pyrrole copolymer P(Py-co-FPy) coated on the carbon microfibers. Due to difficulties of working with carbon microfibers, glassy carbon was used to find out optimized conditions by varying mole ratio of pyrrole and formyl pyrrole monomers on the capacitance value. The prepared electrodes were characterized using Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscope (FESEM), Brunauer-Emmett-Teller (BET) analysis, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Then the X-ray photoelectron spectroscopy (XPS) was used to characterize the optimized electrode. The specific capacitance is calculated using cyclic voltammetry, charge/discharge method, and impedance spectroscopy. The charge/discharge study reveals that the best specific capacitance is estimated to be 220.3 mF cm-2 for equal mole fraction of pyrrole and formyl pyrrole Py (0.1)-FP (0.1) at discharge current of 3 × 10-4 A. This optimized electrode keeps about 92% of its capacitance value in high current of discharging. The specific capacitances calculated by all the mentioned methods are in agreement with each other. Finally, the found optimized conditions were successfully applied to produce a flexible supercapacitor on the surface of carbon microfibers.

  11. Characterization of electro-conductive fabrics prepared by in situ chemical and electrochemical polymerization of pyrrole onto polyester fabric

    Highlights: • Surface resistivity of the fabrics decreased rapidly with an increase in add-on. • Add-on and resistivity were not correlated below a resistivity value of about 200 Ω. • Higher add-on but lower surface roughness resulted in lower surface resistivity. • The voltage–current and voltage–temperature behaviours were found to be non-linear. • Electro-conductive fabric exhibited 98% electromagnetic shielding efficiency. - Abstract: This paper reports a study on electro-conductive fabrics prepared by a combined in situ chemical and electrochemical polymerization of pyrrole. Specific observations are made to establish the roles of add-on and surface roughness on the surface resistivity of the electro-conductive fabrics. The performance characteristics of the fabrics are reported in terms of electrical conductivity, voltage–current and voltage–temperature characteristics and electromagnetic interference (EMI) shielding capability. The surface resistivity of the fabric was found to be as low as 11.79 Ω. The voltage–current profile of the fabric is observed to be non-ohmic as well as the voltage–temperature curve is found to be exponential. The EMI shielding efficiency of the fabric was found to be about 98%

  12. Characterization of electro-conductive fabrics prepared by in situ chemical and electrochemical polymerization of pyrrole onto polyester fabric

    Maiti, Syamal; Das, Dipayan; Sen, Kushal, E-mail: kushal@textile.iitd.ernet.in

    2014-09-15

    Highlights: • Surface resistivity of the fabrics decreased rapidly with an increase in add-on. • Add-on and resistivity were not correlated below a resistivity value of about 200 Ω. • Higher add-on but lower surface roughness resulted in lower surface resistivity. • The voltage–current and voltage–temperature behaviours were found to be non-linear. • Electro-conductive fabric exhibited 98% electromagnetic shielding efficiency. - Abstract: This paper reports a study on electro-conductive fabrics prepared by a combined in situ chemical and electrochemical polymerization of pyrrole. Specific observations are made to establish the roles of add-on and surface roughness on the surface resistivity of the electro-conductive fabrics. The performance characteristics of the fabrics are reported in terms of electrical conductivity, voltage–current and voltage–temperature characteristics and electromagnetic interference (EMI) shielding capability. The surface resistivity of the fabric was found to be as low as 11.79 Ω. The voltage–current profile of the fabric is observed to be non-ohmic as well as the voltage–temperature curve is found to be exponential. The EMI shielding efficiency of the fabric was found to be about 98%.

  13. Design, spectral characterization, DFT and biological studies of transition metal complexes of Schiff base derived from 2-aminobenzamide, pyrrole and furan aldehyde

    Tyagi, Prateek; Chandra, Sulekh; Saraswat, B. S.; Sharma, Deepansh

    2015-05-01

    A series of two biologically active Schiff base ligands L1, L2 have been synthesized in equimolar reaction of 2-aminobenzamide with pyrrol-2-carboxaldehyde and furan-2-carboxaldehyde. The synthesized Schiff bases were used for complexation with different metal ions like Co(II), Ni(II) and Cu(II) by using a molar ratio of ligand: metal as 2:1. The characterization of newly formed complexes was done by 1H NMR, UV-Vis, TGA, IR, mass spectrophotometry, EPR and molar conductivity studies. The thermal studies suggested that the complexes are more stable as compared to ligand. In DFT studies the geometries of Schiff bases and metal complexes were fully optimized with respect to the energy using the 6-31+g(d,p) basis set. On the basis of the spectral studies an octahedral geometry has been assigned for Co(II) and Ni(II) complexes and distorted octahedral geometry for Cu(II) complexes. All the synthesized compounds, were studied for their in vitro antimicrobial activities, against four bacterial strains and two fungal strains by using serial dilution method. The data also revealed that the metal complexes showed better activity than the ligands due to chelation/coordination.

  14. Synthesis and characterization of new electron-withdrawing moiety thieno[2,3-c]pyrrole-4,6-dione-based molecules for small molecule solar cells

    Fu, Lei; Pan, Hongbin; Larsen-Olsen, Thue Trofod;

    2013-01-01

    –π–donor–π–acceptor type end-capped with thieno[2,3-c]pyrrole-4,6-dione (TPD) units for small molecule solar cells have been prepared through coupling of dithienosilole and TPD units bridged with thienylene and bithienylene. They are soluble in common organic solvents and show an interesting absorption. These small...

  15. Synthesis, characterization and computational study on ethyl 4-(3-Furan-2yl-acryloyl)-3,5-dimethyl-1H-pyrrole-2-carboxylate

    Singh, R. N.; Rawat, Poonam; Sahu, Sangeeta

    2014-11-01

    As part of study on pyrrole derivatives, we have synthesized a pyrrole chalcone derivative: ethyl 4-(3-Furan-2yl-acryloyl)-3,5-dimethyl-1H-pyrrole-2-carboxylate (EFADPC) by aldol condensation of ethyl 3, 5-dimethyl-4-actyl-1H-pyrrole-2-carboxylate with furan-2-carbaldehyde in the presence of strong hydroxyl base as catalyst. The product EFADPC has been confirmed by spectroscopic (FT-IR, 1H NMR, and UV-visible) analyses. Quantum chemical calculation also provides good correlation with experimental data. The molecular electrostatic potential surface (MEP), natural bond orbital interactions (NBO), electronic descriptors, quantum theory of atoms' in molecules (QTAIM) and experimental FT-IR spectrum have been used to predict the sites and nature of interactions which indicate that the dimer formation with multiple interactions through Nsbnd H···O and Csbnd H···O. The vibrational analysis shows red shifts in νNsbnd H and νCdbnd O as result of dimer formation. The binding energy of dimer is calculated as 13.82, 15.24 kcal/mol using DFT, QTAIM analysis, respectively. The result of ellipticity confirms the existence of resonance assisted hydrogen bonds (RAHB) in dimer. The MEP and local reactivity descriptors analyses have been performed and the results indicate that carbonyl carbon and β-carbon of chalcone frame have been prone to nucleophilic attack and lead to large number of heterocyclic compounds such as oxirane, oxazoles, pyrazoles, pyridines, pyrimidines, and pyran.

  16. Preparation of ultrathin pyrrolic conductor films as backings of radioactive sources

    A procedure for electropolymerization of pyrrole has been set up in order to produce thin (> 15 μ g/cm2) homogeneous (thickness variation 2. The experimental equipment, reagent and procedure utilized is described as well as the characterization pyrrolic films produced

  17. Synthesis of new pyrrole-containing biomolecules as building blocks for functionalized polypyrroles in nanobiotechnology

    New pyrroles were synthesized wherein biomolecules such as α-amino acids, peptides or carbohydrates are attached to position 1 or 3 via suitable linkers. These conjugates were copolymerized with pyrrole by chemical polymerisation alone giving corresponding copolymers or in the presence of magnetic iron oxid nanoparticles resulting in functionalized core-shell-nanoparticles. Such products are interesting for biosensing, imaging or separation of biomaterials. They were characterized by several methods such as TEM, HRTEM, FTIR and measuring of magnetization.

  18. Study on the nature of interaction of pyrrole with various hydrides

    Graphical abstract: The equilibrium geometries of the pyrrole-HnX (X=F, O, N, Cl, S and P) complexes are shown in above figure. These geometries are classified as N-H...X type and H-π-type (also referred to in this paper as geometry types I and II, respectively). The N-H...X type geometry features a hydrogen bond formed between the hydrogen atom of pyrrole and X atom of HnX, and has C1 symmetry. The π-type geometry is characterized by an H-π bond formed between a hydrogen atom of HnX and the π-electron system of the aromatic ring, and has C1 symmetry. For the pyrrole-HF, H2O, NH3, H2S and -PH3 complexes have N-H...X type and π-type. For the pyrrole-HCl complexes have only H-π-type. Display Omitted Highlights: → We investigated the intermolecular interaction of pyrrole with the various hydrides. → There are N-H...X and H-π-type hydrogen-bonding complexes. → With the exception of pyrrole-H2O and pyrrole-NH3 complexes, all of the other pyrrole-HnX complexes favors π-type H-bonding. → The electrostatic and dispersion interactions dominate the H-π-type complexes. - Abstract: Equilibrium geometries, interaction energies, atomic charge, and charge transfer for the N-H...X and H-π-type hydrogen-bonding complexes between pyrrole and various hydrides HnX (X=F, O, N, Cl, S, and P) were studied at the MP2/aug-cc-pVDZ level. With the exception of pyrrole-H2O and pyrrole-NH3 complexes, all of the other pyrrole-HnX complexes favors π-type H-bonding. To further study the nature of the π-type H-bonding, an SAPT (the symmetry adapted perturbation theory) energy decomposition analysis was carried out and the results indicate that the electrostatic and dispersion interactions dominate the H-π-type complexes.

  19. Syntheses of Calix[4]Pyrroles by Amberlyst-15 Catalyzed Cyclocondensations of Pyrrole with Selected Ketones

    Tanuja Bisht

    2007-11-01

    Full Text Available A facile and efficient protocol is reported for the synthesis of calix[4]pyrrolesand N-confused calix[4]pyrroles in moderate to excellent yields by reaction of dialkyl orcycloalkyl ketones with pyrrole catalyzed by reusable AmberlystTM-15 under eco-friendlyconditions.

  20. Synthesis of hollow poly(aniline-co-pyrrole)-Fe3O4 composite nanospheres and their microwave absorption behavior

    Zhu, Yao-Feng; Zhang, Li; Natsuki, Toshiaki; Fu, Ya-Qin; Ni, Qing-Qing

    2012-01-01

    Hollow poly(aniline-co-pyrrole)-Fe3O4 (HPAP-Fe3O4) nanospheres with significant electromagnetic properties were successfully prepared via the oxidative polymerization of a mixture of aniline and pyrrole in the presence of a magnetic fluid, using a non-ionic surfactant as a template. The products were characterized by field emission scanning electron microscopy, transmission electron microscopy. Fourier transform infrared spectroscopy, X-ray powder diffraction, thermogravimetric analysis and X...

  1. Electrophilic surface sites as precondition for the chemisorption of pyrrole on GaAs(001) surfaces

    We report how the presence of electrophilic surface sites influences the adsorption mechanism of pyrrole on GaAs(001) surfaces. For this purpose, we have investigated the adsorption behavior of pyrrole on different GaAs(001) reconstructions with different stoichiometries and thus different surface chemistries. The interfaces were characterized by x-ray photoelectron spectroscopy, scanning tunneling microscopy, and by reflectance anisotropy spectroscopy in a spectral range between 1.5 and 5 eV. On the As-rich c(4 × 4) reconstruction that exhibits only nucleophilic surface sites, pyrrole was found to physisorb on the surface without any significant modification of the structural and electronic properties of the surface. On the Ga-rich GaAs(001)-(4 × 2)/(6 × 6) reconstructions which exhibit nucleophilic as well as electrophilic surface sites, pyrrole was found to form stable covalent bonds mainly to the electrophilic (charge deficient) Ga atoms of the surface. These results clearly demonstrate that the existence of electrophilic surface sites is a crucial precondition for the chemisorption of pyrrole on GaAs(001) surfaces

  2. Pyrrole-added Fe2O3 films by ultrasonic spray pyrolisis

    Carlos Torres Frausto; Alejandro Avila Garcia

    2009-01-01

    Fe2O3 thin films were grown by Ultrasonic Spray Pyrolisis from a 0.05 aqueous solution of FeCl3 added with a small amount of pyrrole monomer. Films at different substrate temperature and pyrrole content were grown. They were characterized by using x-ray diffraction (XRD), infrared spectroscopy (FTIR) and atomic force microscopy (AFM). Results indicated that at low substrate temperature (approximately 200ºC) the films mainly resemble the polypyrrole structure. At higher temperatures up to 400...

  3. Tris[2-(pyrrol-2-ylmethyleneaminoethyl]amine

    Hongbing Fu

    2008-03-01

    Full Text Available The title compound, C21H27N7, was synthesized by reaction of tris(2-aminoethylamine and pyrrole-2-carbaldehyde in ethanol at room temperature. The structure is stabilized by intra- and intermolecular C—H...N and N—H...N hydrogen-bonding interactions.

  4. Synthesis, autoxidation and photooxidation of hindered pyrrole derivatives. Hindered pyrrolic nitroxide radicals

    2,5-di-t-butyl and 2,3,5-tri-t-butyl pyrrole are prepared from pinacoline and their structure is confirmed by comparison with 2,5-di-t-butyl furan and thiophene (I.R., U.V. and N.M.R. 13C satellites observation giving J13C-H and JH3-H4). The sensitized photooxidation of these hindered pyrroles gives corresponding hydroperoxides which most likely structure is determined using physical and chemical methods. Oxidation of 2,5-di-t-butyl and 2,3,5-tri-t-butyl pyrrole by hydrogen peroxide in presence of inorganic per-acid of by p-nitro-perbenzoic acid does not give the pyrrolic nitroxides in contrast with secondary amines. Some N-hydroxypyrroles are then prepared from pinacoline and ethyl pivaloyl-acetate. Their oxidation by lead dioxide gives the corresponding pyrrolic nitroxides. 2,5-di-t-butyl 3,4-di-ethoxycarbonyl pyrryl 1-oxy is isolated and studied spectroscopically (visible and U.V., E.P.R.). In marked contrast with ordinary nitroxides it does not show solvent effect. It can be compared with 2,4-di-t-butyl cyclopentadienone, a carbon analog. For both, the long wave length transition does not show the usual n - π* behaviour; that is confirmed by E.P.R. Using Huckel method for pyrrolic nitroxide skeleton, it is possible to have a good interpretation of experimental data. (author)

  5. The electrochemical synthesis of poly(pyrrole-co-o-anisidine) on 3102 aluminum alloy and its corrosion protection properties

    Mert, B. Dogru, E-mail: bdogru@cu.edu.tr [Cukurova University, Science and Letters Faculty, Chemistry Department, 01330 Balcali, Adana (Turkey); Yazici, B. [Cukurova University, Science and Letters Faculty, Chemistry Department, 01330 Balcali, Adana (Turkey)

    2011-02-15

    Research highlights: {yields} The electrochemical synthesis of strongly adherent, uniform polypyrrole (PPy) and poly(pyrrole-co-o-anisidine) coatings were successfully achieved on 3102 aluminum alloy from 0.1 M monomer (pyrrole and pyrrole:o-anisidine, 8:2) containing oxalic acid by means of the cyclic voltammetry technique. {yields} The results were showed that the water permeation of copolymer coating is lower than PPy. {yields} This study was showed that copolymer is suitable coating for protection of 3102 Al alloy against corrosion. - Abstract: The electrochemical syntheses of polypyrrole (PPy) and poly(pyrrole-co-o-anisidine) were achieved on 3102 aluminum alloy (Al) from 0.1 M monomer (pyrrole:o-anisidine, 8:2) containing 0.4 M oxalic acid solution using the cyclic voltammetry technique. The synthesized films were characterized by FT-IR spectroscopy. The thermal stability of films was determined by thermogravimetric analysis (TGA) technique. Surface morphologies were characterized by scanning electron microscope (SEM) images. The potential of zero charge (pzc) of Al was determined using electrochemical impedance spectroscopy (EIS). The corrosion behavior of samples was investigated with open circuit potential (E{sub ocp})-time, EIS, and anodic polarization techniques. It was found that copolymer coated Al provides better barrier property against of corrosion in 3.5% NaCl solution.

  6. Preparation of conductive membranes using poly pyrrole

    Conductive membranes show many benefits including fouling reduction for feeds containing ionic species. These membranes may be prepared either by conductive polymers or coating of the surfaces of non-conductive membranes with conductive polymer. In this research, the commercial micro filtration GVHP membrane manufactured from PVDF was coated with poly pyrrole using two different techniques. The conductivity of the prepared membranes was measured. In this paper, effects of various factors including concentration of the solutions, oxidizing agents, time for leaving the support in the solutions, support type and temperature on membrane conductivity were investigated

  7. Revisiting the relaxation dynamics of isolated pyrrole

    Montero, Raúl; Ovejas, Virginia; Fernández-Fernández, Marta; Longarte, Asier, E-mail: asier.longarte@ehu.es [Departamento de Química Física, Universidad del País Vasco (UPV/EHU), Apart. 644, 48080 Bilbao (Spain); Peralta Conde, Álvaro [Centro de Láseres Pulsados (CLPU), Edificio M3, Parque Científico, 37185 Villamayor (Spain)

    2014-07-07

    Herein, the interpretation of the femtosecond-scale temporal evolution of the pyrrole ion signal, after excitation in the 267–217 nm interval, recently published by our group [R. Montero, A. Peralta Conde, V. Ovejas, M. Fernández-Fernández, F. Castaño, J. R. Vázquez de Aldana, and A. Longarte, J. Chem. Phys.137, 064317 (2012)] is re-visited. The observation of a shift in the pyrrole{sup +} transient respect to zero delay reference, initially attributed to ultrafast dynamics on the πσ{sup *} type state (3s a{sub 1} ← π 1a{sub 2}), is demonstrated to be caused by the existence of pump + probe populated states, along the ionization process. The influence of these resonances in pump-prone ionization experiments, when multi-photon probes are used, and the significance of a proper zero-time reference, is discussed. The possibility of preparing the πσ{sup *} state by direct excitation is investigated by collecting 1 + 1 photoelectron spectra, at excitation wavelengths ranging from 255 to 219 nm. No conclusive evidences of ionization through this state are found.

  8. Living on pyrrolic foundations - Advances in natural and artificial bioactive pyrrole derivatives.

    Domagala, Anna; Jarosz, Tomasz; Lapkowski, Mieczyslaw

    2015-07-15

    Pyrrole, a simple heterocyclic system, is an important building block for numerous biologically active compounds both natural and synthetic in origin, which boast an immense array of qualities, baleful and beneficial alike. The latter have given rise to a bountiful variety of pyrrole-based drugs, with many more being designed, developed and applied each year, as evidenced by the amount of entries in the Cambridge Structural Database skyrocketing from about six hundred in 2004 to more than a thousand over the course of the last decade. Particularly important in light of the ever-encroaching menace of drug-resistant bacteria, the vast progress in the field necessitates a sound organisational framework and summary - a task, to which we contribute this summary and checklist of the most recent developments, indicating the classes of compounds, which have attracted the most significant research attention. PMID:26087028

  9. Hydrolytic study of the copolymer Poly pyrrole/ Polyethyleneglycol and Poly pyrrole synthesized by plasma

    In this work the study about the hydrolytic compatibility of semiconductor polymers, copolymer Poly pyrrole/ Polyethyleneglycol (PPy/PEG) and Poly pyrrole (PPy) for their possible use as biomaterials. The polymers were synthesized by plasma between 10 and 100 W, with discharges of splendor RF to 13.5 MHz with resistive coupling. The hydrolytic affinity was evaluated calculating the contact angle with solutions of NaCl, NaCl-MgSO4 and Krebs-Ringer. The results show a hydrophilicity increment due to the increase of the surface ruggedness with the synthesis energy. On the contrary, the crystallinity diminishes when increasing the power in PPy and it stays approximately constant in PPy/PEG. The electric conductivity presents a growth from 2 to 4 magnitude orders in function of the water content in the polymers. (Author)

  10. Hydroquinone-pyrrole dyads with varied linkers.

    Huang, Hao; Karlsson, Christoffer; Strømme, Maria; Sjödin, Martin; Gogoll, Adolf

    2016-01-01

    A series of pyrroles functionalized in the 3-position with p-dimethoxybenzene via various linkers (CH2, CH2CH2, CH=CH, C≡C) has been synthesized. Their electronic properties have been deduced from (1)H NMR, (13)C NMR, and UV-vis spectra to detect possible interactions between the two aromatic subunits. The extent of conjugation between the subunits is largely controlled by the nature of the linker, with the largest conjugation found with the trans-ethene linker and the weakest with the aliphatic linkers. DFT calculations revealed substantial changes in the HOMO-LUMO gap that correlated with the extent of conjugation found experimentally. The results of this work are expected to open up for use of the investigated compounds as components of redox-active materials in sustainable, organic electrical energy storage devices. PMID:26877811

  11. Hydroquinone–pyrrole dyads with varied linkers

    Huang, Hao; Karlsson, Christoffer; Strømme, Maria; Sjödin, Martin

    2016-01-01

    Summary A series of pyrroles functionalized in the 3-position with p-dimethoxybenzene via various linkers (CH2, CH2CH2, CH=CH, C≡C) has been synthesized. Their electronic properties have been deduced from 1H NMR, 13C NMR, and UV–vis spectra to detect possible interactions between the two aromatic subunits. The extent of conjugation between the subunits is largely controlled by the nature of the linker, with the largest conjugation found with the trans-ethene linker and the weakest with the aliphatic linkers. DFT calculations revealed substantial changes in the HOMO–LUMO gap that correlated with the extent of conjugation found experimentally. The results of this work are expected to open up for use of the investigated compounds as components of redox-active materials in sustainable, organic electrical energy storage devices. PMID:26877811

  12. Electrochemical impedance of poly(9-tosyl-9H-carbazole-co-pyrrole) electrocoated carbon fiber

    Research highlights: → Impedance study of poly(9-tosyl-9H-carbazole-co-pyrrole) electrocoated carbon fiber. → Copolymer of 9-tosyl-9H-carbazole and pyrrole were electrocoated on carbon fiber. → Impedance spectroscopy and circuit models of poly(9-tosyl-9H-carbazole-co-pyrrole). - Abstract: In this paper, copolymer of 9-tosyl-9H-carbazole (TCz) and pyrrole (Py) comonomers were electrochemically deposited onto carbon fiber micro electrode (CFME) as an active electrode material. An electrochemical impedance study on the prepared electrodes is reported. Poly(TCz-co-Py)/CFME is characterized by cyclic voltammetry (CV), Fourier transform infrared reflectance-attenuated total reflection spectroscopy (FTIR-ATR), scanning electron microscopy-energy dispersive X-ray analysis (SEM-EDX), and electrochemical impedance spectroscopy (EIS). Capacitive behaviors of modified CFMEs were defined via Nyquist, Bode-magnitude and Bode-phase plots. An examination is made of which equivalent circuits of R(C(R(Q(RW)))) and R(C(R(Q(RW))))(CR) used for modeling the system. The effect of monomer ratio (mole fraction, XTCz = nTCz/nTCz + nPy) on the formation of copolymer is reported in 0.1 M sodium perchlorate (NaClO4)/acetonitrile (ACN) solution. The inclusion of TCz in the copolymer structure was also confirmed by FTIR-ATR, SEM, and CV measurements. The highest low frequency capacitance (CLF = 22.7 for R(C(R(Q(RW)))) and CLF = 22.6 mF cm-2 for R(C(R(Q(RW))))(CR)) were obtained for XTCz = 0.91.

  13. Polymerization of Pyrrole and Thiophene on Polyethylene Adipate Electrodes

    ERTURAN, Seyfettin; TORAMAN, Burcu YALVAÇ and Sena

    1998-01-01

    Polymerizations of pyrrole and thiophene on a platinum foil coated by polyethylene adipate (PEA) were carried out in acetonitrile by electrochemical methods. Different compositions of semi-conducting composite films of PEA/Polypyrrole(PPy), PEA/Polythiophene(PT) were prepared by the electrochemical polymerization of pyrrole and thiophene on PEA electrode. The polymerization was possible only for a certain thickness of the polyethylene adipate(PEA) on the platinum. Conductivities of PEA/PPy, P...

  14. Simple two-step synthesis of 2,4-disubstituted pyrroles and 3,5-disubstituted pyrrole-2-carbonitriles from enones

    Murat Kucukdisli

    2014-02-01

    Full Text Available The cyclocondensation of enones with aminoacetonitrile furnishes 3,4-dihydro-2H-pyrrole-2-carbonitriles which can be readily converted to 2,4-disubstituted pyrroles by microwave-induced dehydrocyanation. Alternatively, oxidation of the intermediates produces 3,5-disubstituted pyrrole-2-carbonitriles.

  15. Interaction of derived polymers from pyrrole with biocompatible solutions

    This work presents a study about the synthesis by plasma, the electric properties and superficial interaction of polymers derived from pyrrole doped with Iodine with potential use as bio material. Poly-pyrrole is a semiconductor and biocompatible polymer with potential application in the development of artificial muscles and implants where the electric interaction between cells and material is an important variable. The syntheses were made at 13.5 MHz in a glass tubular reactor of 1500 cm3 with electrodes of 6.5 cm diameter and stainless steel flanges. An electrode was connected to the RF terminal of the power supply that is combined with a matching coupling resistance. The monomer and dopant used in this work were pyrrole and Iodine respectively, in closed containers. They were vaporized and injected separately into the reactor at room temperature and 0.1 mbar. The vapors of the reagents mixed freely in the reactor. The synthesis time was 240 min at 40, 60, 80 and 100 W. The polymers were obtained as thin films adhered to the reactor walls. The films were washed and swollen with distilled water and removed from the reactor walls with a small spatula. The polymers were irradiated with gamma rays at 18 and 22 KGy. Due to the fact that the doses are cumulative, the final dose applied was 40 KGy. The polymers characterization was carried out by Fourier Transform Infrared Spectroscopy, thermogravimetric analysis (TGA), scanning electron microscopy, contact angle, electrical conductivity and X-ray diffraction. The analyses indicates that the polymers have very similar structure in almost the entire power range, showing C-O, C=C, C-H, O-H, N-H bonds with a predominantly amorphous structure. The TGA analyses showed that the material has 4 or 5 loses of material. The first one starts after that 115 C except for the material irradiated at 40 KGy, this one begins in 87 C, the second one is in the interval of 196 and 295 C, the third one between 311 and 500 C, and the last

  16. Reactions of a Ruthenium Complex with Substituted N-Propargyl Pyrroles.

    Chia, Pi-Yeh; Huang, Shou-Ling; Liu, Yi-Hong; Lin, Ying-Chih

    2016-04-01

    In an investigation into the chemical reactions of N-propargyl pyrroles 1 a-c, containing aldehyde, keto, and ester groups on the pyrrole ring, with [Ru]-Cl ([Ru]=Cp(PPh3 )2 Ru; Cp=C5 H5 ), an aldehyde group in the pyrrole ring is found to play a crucial role in stimulating the cyclization reaction. The reaction of 1 a, containing an aldehyde group, with [Ru]-Cl in the presence of NH4 PF6 yields the vinylidene complex 2 a, which further reacts with allyl amine to give the carbene complex 6 a with a pyrrolizine group. However, if 1 a is first reacted with allyl amine to yield the iminenyne 8 a, then the reaction of 8 a with [Ru]-Cl in the presence of NH4 PF6 yields the ruthenium complex 9 a, containing a cationic pyrrolopyrazinium group, which has been fully characterized by XRD analysis. These results can be adequately explained by coordination of the triple bond of the propargyl group to the ruthenium metal center first, followed by two processes, that is, formation of a vinylidene intermediate or direct nucleophilic attack. Additionally, the deprotonation of 2 a by R4 NOH yields the neutral acetylide complex 3 a. In the presence of NH4 PF6 , the attempted alkylation of 3 a resulted in the formation the Fischer-type amino-carbene complex 5 a as a result of the presence of NH3 , which served as a nucleophile. With KPF6 , the alkylation of 3 a with ethyl and benzyl bromoacetates afforded the disubstituted vinylidene complexes 10 a and 11 a, containing ester groups, which underwent deprotonation reactions to give the furyl complexes 12 a and 13 a, respectively. For 13 a, containing an O-benzyl group, subsequent 1,3-migration of the benzyl group was observed to yield product 14 a with a lactone unit. Similar reactivity was not observed for the corresponding N-propargyl pyrroles 1 b and 1 c, which contained keto and ester groups, respectively, on the pyrrole ring. PMID:26865008

  17. Electrogenerated poly(pyrrole-lactosyl and poly(pyrrole-3’-sialyllactosyl interfaces: towards the impedimetric detection of lectins

    Chantal eGondran

    2013-07-01

    Full Text Available This paper reports on the impedimetric transduction of binding reaction between polymerized saccharides and target lectins. The controlled potential electro-oxidation of pyrrole-lactosyl and pyrrole-3’-sialyllactosyl at 0.95 V vs Ag/AgCl, provides thin and reproducible poly(pyrrole-saccharide films. The affinity binding of two lectins: Arachis hypogaea, (PNA and Maackia amurensis (MAA onto poly(pyrrole-lactosyl and poly(pyrrole-3’-sialyllactosyl electrodes, was demonstrated by cyclic voltammetry in presence of ruthenium hexamine and hydroquinone. In addition, rotating disk experiments were carried out to determine the permeability of both polypyrrole films and its evolution after incubating with lectin target. Finally, the possibility of using the poly(pyrrole-lactosyl or poly(pyrrole-3’-siallyllactosyl films for the impedimetric transduction of the lectin binding reaction, was investigated with hydroquinone (2×10-3 mol L-1 as a redox probe in phosphate buffer. The resuting impedance spectra were interpreted and modeled as an equivalent circuit indicating that charge transfer resistance (Rct and relaxation frequency (f° parameters are sensitive to the lectin binding. Rct increases from 77 to 97 Ω cm2 for PNA binding and from 93 to 131 Ω cm2 for MAA binding. In parallel, f° decreases from 276 to 222 Hz for PNA binding and from 223 to 131 Hz for MAA binding. This evolution of both parameters reflects the steric hindrances generated by the immobilised lectins towards the permeation of the redox probe.

  18. Electrogenerated poly(pyrrole-lactosyl) and poly(pyrrole-3'-sialyllactosyl) interfaces: towards the impedimetric detection of lectins

    Gondran, Chantal; Dubois, Marie-Pierre; Fort, Sebastien; Cosnier, Serge

    2013-07-01

    This paper reports on the impedimetric transduction of binding reaction between polymerized saccharides and target lectins. The controlled potential electro-oxidation of pyrrole-lactosyl and pyrrole-3’-sialyllactosyl at 0.95 V vs Ag/AgCl, provides thin and reproducible poly(pyrrole-saccharide) films. The affinity binding of two lectins: Arachis hypogaea, (PNA) and Maackia amurensis (MAA) onto poly(pyrrole-lactosyl) and poly(pyrrole-3’-sialyllactosyl) electrodes, was demonstrated by cyclic voltammetry in presence of ruthenium hexamine and hydroquinone. In addition, rotating disk experiments were carried out to determine the permeability of both polypyrrole films and its evolution after incubating with lectin target. Finally, the possibility of using the poly(pyrrole-lactosyl) or poly(pyrrole-3’-siallyllactosyl) films for the impedimetric transduction of the lectin binding reaction, was investigated with hydroquinone (2×10-3 mol L-1) as a redox probe in phosphate buffer. The resuting impedance spectra were interpreted and modeled as an equivalent circuit indicating that charge transfer resistance (Rct) and relaxation frequency (f°) parameters are sensitive to the lectin binding. Rct increases from 77 to 97 Ω cm2 for PNA binding and from 93 to 131 Ω cm2 for MAA binding. In parallel, f° decreases from 276 to 222 Hz for PNA binding and from 223 to 131 Hz for MAA binding. This evolution of both parameters reflects the steric hindrances generated by the immobilised lectins towards the permeation of the redox probe.

  19. Synthesis and recognition properties of higher order tetrathiafulvalene (TTF) calix n pyrroles (n=4-6)

    Park, J. S.; Bejger, C.; Larsen, K. R.; Nielsen, K. A.; Jana, A.; Lynch, V. M.; Jeppesen, J. O.; Kim, D.; Sessler, J. L.

    2012-01-01

    proves most effective for the recognition of TNB and TNT. These findings are rationalized in terms of the number of electron rich TTF subunits and NH hydrogen bond donor groups within the series, as well as an ability to adopt conformations suitable for substrate recognition, and are supported by solid...... the condensation reaction, the expanded calix[n]pyrroles (n = 5 and 6) are characterized by a larger cavity size and a higher number of TTF units (albeit the same empirical formula). Analysis of the binding isotherms obtained from UV-Vis spectroscopic titrations carried out in CHCl3 in the presence of...

  20. Zinc hexacyanoferrate film as an effective protecting layer in two-step and one-step electropolymerization of pyrrole on zinc substrate

    The two-step and one-step electrosynthesis processes of polypyrrole (PPy) films on the zinc substrate are described. The two-step process includes (i) the zinc surface pretreatment with hexacyanoferrate ion in the aqueous medium in order to form a zinc hexacyanoferrate (ZnHCF) film non-blocking passive layer on the surface and with the view to prevent its reactivity and (ii) electropolymerization of pyrrole on the ZnHCF vertical bar Zn-modified electrode in aqueous pyrrole solution. In this context, both the non-electrolytic and electrolytic procedures were adapted, and the effect of some experimental conditions such as supporting electrolyte, pH and temperature of the solution at the zinc surface pretreatment step as well as pyrrole concentration and electrochemical techniques at the polymerization step was investigated. By optimizing the experimental conditions in both steps, we have obtained a homogeneous and strongly adherent PPy films on the zinc substrate. The one-step process is based on the use of an aqueous medium containing Fe(CN)64- and pyrrole. The ferrocyanide ion passivates the substrate by formation of ZnHCF film during the electropolymerization process of pyrrole and therefore makes it possible to obtain strongly adherent PPy films, with controlled thickness, either by cyclic voltammetry or by electrolysis at constant current or constant potential without any previously treatment of the zinc electrode surface. The polypyrrole films deposited on the zinc electrode were characterized by cyclic voltammetry and scanning electron microscopic (SEM) measurement

  1. The first direct synthesis of β-unsubstituted meso-decamethylcalix[5]pyrrole

    Chacón-García, Luis; Chávez, Lizbeth; Cacho, Denisse R; Altamirano-Hernández, Josue

    2009-01-01

    The first direct synthesis of β-unsubstituted meso-decamethylcalix[5]pyrrole from pyrrole and acetone, with moderate yield, is described. The results showed that a bismuth salt was necessary to obtain calix[5]pyrrole, with the best results obtained using Bi(NO3)3.

  2. The first direct synthesis of β-unsubstituted meso-decamethylcalix[5]pyrrole

    Luis Chacón-García; Lizbeth Chávez; Cacho, Denisse R; Josue Altamirano-Hernández

    2009-01-01

    The first direct synthesis of β-unsubstituted meso-decamethylcalix[5]pyrrole from pyrrole and acetone, with moderate yield, is described. The results showed that a bismuth salt was necessary to obtain calix[5]pyrrole, with the best results obtained using Bi(NO3)3.

  3. Hydrazonoyl Chlorides as Precursors for Synthesis of Novel Bis-Pyrrole Derivatives

    Nabila Abdelshafy Kheder

    2016-01-01

    A convenient synthesis of some novel bis-pyrrole derivatives via hydrazonoyl halides is described. Antimicrobial evaluation of some selected examples of the synthesized products was carried out. The bis-pyrrole derivative having chloro substituents showed good activity against all of the used microbes. The molecular docking of the bis-pyrrole derivatives was performed by the Molecular Operating Environment (MOE) program.

  4. Biofabrication Using Pyrrole Electropolymerization for the Immobilization of Glucose Oxidase and Lactate Oxidase on Implanted Microfabricated Biotransducers

    Christian N. Kotanen; Olukayode Karunwi; Anthony Guiseppi-Elie

    2014-01-01

    The dual responsive Electrochemical Cell-on-a-Chip Microdisc Electrode Array (ECC MDEA 5037) is a recently developed electrochemical transducer for use in a wireless, implantable biosensor system for the continuous measurement of interstitial glucose and lactate. Fabrication of the biorecognition membrane via pyrrole electropolymerization and both in vitro and in vivo characterization of the resulting biotransducer is described. The influence of EDC-NHS covalent conjugation of glucose oxidas...

  5. Versatile functionalization of nanoelectrodes by oligonucleotides via pyrrole electrochemistry.

    Descamps, Emeline; Nguyen, Khoa; Bouchain-Gautier, Christelle; Filoramo, Arianna; Goux-Capes, Laurence; Goffman, Marcello; Bourgoin, Jean-Philippe; Mailley, Pascal; Livache, Thierry

    2010-11-15

    Surface modification at the nanometer scale is a challenge for the future of molecular electronics. In particular, the precise anchoring and electrical addressing of biological scaffolds such as complex DNA nanonetworks is of importance for generating bio-directed assemblies of nano-objects for nanocircuit purposes. Herein, we consider the individual modification of nanoelectrodes with different oligonucleotide sequences by an electrochemically driven co-polymerization process of pyrrole and modified oligonucleotide sequences bearing pyrrole monomers. We demonstrate that this one-step technique presents the advantages of simplicity, localization of surface modification, mechanical, biological and chemical stability of the coatings, and high lateral resolution. PMID:20973021

  6. A colorimetric tetrathiafulvalene-calix 4 pyrrole anion sensor

    Nielsen, K. A.

    2012-01-01

    The interaction and colorimetric sensing properties of a tetrathiafulvalene substituted calix[4]pyrrole sensor with anions were investigated using H-1 NMR and absorption spectroscopic techniques. Visual color changes were observed upon addition of different anions (Cl-, Br-, CN-, and AcO-) to a s...

  7. Both visual and fluorescent sensors for Zn(2+) based on bis(pyrrol-2-yl-methyleneamine) platform.

    Wu, Wei-Na; Mao, Pan-Dong; Jia, Lei; Wang, Yuan; Xu, Zhou-Qing

    2016-09-01

    Two bis(pyrrol-2-yl-methyleneamine) chemo-sensors, 1, 3- and 1, 4-bis[3,4-dimethyl-5-ethyloxy -carbonyl-pyrrol-2-yl-methyleneamine]benzene (H2L(1) and H2L(2), respectively) have been synthesized and characterized, which exhibit high selectivity as off-on fluorescence sensors toward Zn(2+) in CH3CN/H2O (9:1, v/v) solution. The detection limits of both sensors are at the parts per million level. Moreover, the probes H2L(1) and H2L(2) could sense Zn(2+) by "naked eye" with a color change from colorless to yellow, and from yellow to dark yellow, respectively. To test the practical use of the probes, the determination of Zn(2+) in real water samples was also evaluated. PMID:27208758

  8. Both visual and fluorescent sensors for Zn2 + based on bis(pyrrol-2-yl-methyleneamine) platform

    Wu, Wei-Na; Mao, Pan-Dong; Jia, Lei; Wang, Yuan; Xu, Zhou-Qing

    2016-09-01

    Two bis(pyrrol-2-yl-methyleneamine) chemo-sensors, 1, 3- and 1, 4-bis[3,4-dimethyl-5-ethyloxy -carbonyl-pyrrol-2-yl-methyleneamine]benzene (H2L1 and H2L2, respectively) have been synthesized and characterized, which exhibit high selectivity as off-on fluorescence sensors toward Zn2 + in CH3CN/H2O (9:1, v/v) solution. The detection limits of both sensors are at the parts per million level. Moreover, the probes H2L1 and H2L2 could sense Zn2 + by "naked eye" with a color change from colorless to yellow, and from yellow to dark yellow, respectively. To test the practical use of the probes, the determination of Zn2 + in real water samples was also evaluated.

  9. Poly(1-(2-carboxyethyl)pyrrole)/polypyrrole composite nanowires for glucose biosensor

    A novel glucose biosensor based on poly(1-(2-carboxyethyl)pyrrole) (PPyCOOH)/polypyrrole (PPy) composite nanowires was developed by immobilizing glucose oxidase (GOD) on the nanowires via covalent linkages. The PPyCOOH/PPy composite nanowires were fabricated by a facile two-step electrochemical synthesis route. First, PPy nanowires were synthesized in phosphate buffer solution using organic sulfonic acid, p-toluenesulfonate acid, as soft-template. Then, PPyCOOH/PPy composite nanowires were obtained by polymerizing 1-(2-carboxyethyl)pyrrole onto PPy nanowires via electrochemical method. Scanning electron microscopic, FT-IR spectra, X-ray photoelectron spectroscopy and cyclic voltammograms were used to characterize the structural and electrical behaviors of the composite nanowires. The PPyCOOH/PPy composite nanowires exhibited uniform diameter, high reactive site (-COOH), large specific surface, excellent electroactivity and good adhesion to electrode. The glucose biosensor was constructed by covalently coupling GOD to the composite nanowires. The biosensor response was rapid (5 s), highly sensitive (33.6 μA mM−1 cm−2) with a wide linear range (up to 10.0 mM) and low detection limit (0.63 μM); it also exhibited high stability and specificity to glucose. The attractive electrochemical and structural properties of PPyCOOH/PPy composite nanowires suggested potential application for electrocatalysis and biosensor.

  10. Calix[4]pyrrole-based ion pair receptors.

    Kim, Sung Kuk; Sessler, Jonathan L

    2014-08-19

    Ion pair receptors, which are able to bind concurrently both a cation and an anion, often display higher selectivity and affinity for specific ion pairs than simple ion receptors capable of recognizing primarily either a cation or an anion. This enhancement in recognition function is attributable to direct or indirect cooperative interactions between cobound ions via electrostatic attractions between oppositely charged ions, as well as to positive allosteric effects. In addition, by virtue of binding the counterions of the targeted ion, ion pair receptors can minimize the solvation of the counterions, which can otherwise have a negative effect on the interactions between the receptors and the targeted ions. As a result of their more favorable interactions, ion pair receptors are attractive for use in applications, such as extraction and sensing, where control of the binding interactions is advantageous. In this Account, we illustrate this potential in the context of ion pair receptors based on the calix[4]pyrrole scaffold. Both simple ditopic ion pair receptors, containing sites for the recognition of a single anion and single cation, and so-called multitopic ion pair receptors will be discussed. The latter systems differ from conventional, so-called ditopic ion pair receptors in that they contain more than one binding site for a given targeted ion (e.g., a cation). This permits a level of selectivity and control over binding function not normally seen for simple ion or ion pair receptors containing one or two binding sites, respectively. Calix[4]pyrroles are macrocyclic compounds consisting of four pyrrole units linked via fully substituted sp(3) hybridized meso carbon atoms. They are effective receptors for Lewis basic anions (e.g., halides) in typical organic media and under certain conditions will recognize ion pairs containing charge diffuse cations, such as a small alkylammonium, imidazolium, or cesium cations. The calix[4]pyrrole framework is further

  11. Calix[4]pyrrole derivative: recognition of fluoride and mercury ions and extracting properties of the receptor-based new material.

    de Namor, Angela F Danil; Khalife, Rasha

    2008-12-11

    A calix[4]pyrrole derivative, namely, meso-tetramethyl tetrakis (4-phenoxy methyl ketone) calix[4]pyrrole, 1, was synthesized and structurally (1H NMR) and thermodynamically characterized. The complexing properties of this receptor with a wide variety of anions and cations in dipolar aprotic media (acetonitrile, propylene carbonate, and dimethyl sulfoxide) were investigated through 1H NMR and conductance studies. The former technique was used to assess whether or not complexation occurs and if so to identify the active sites of interaction of 1 with ions. The composition of the complexes was established by conductance measurements. It was found that in dipolar aprotic solvents, 1 interacts only with two polluting ions (fluoride and mercury). The complexation thermodynamics of 1 and these ions in these solvents is reported. The medium effect on the binding process involving the fluoride ion is discussed taking into account the solvation properties of reactants and the product. Complexes of moderate stability are found. Given that this is an important factor to consider for the recycling of the loaded material in extraction processes, 1 was treated with formaldehyde in basic medium leading to the production of a calix[4]pyrrole based material able to extract fluoride and mercury (II) ions from water. Thus the optimum conditions for the extraction of these ions from aqueous solutions were established. The material is easily recyclable using an organic acid. Final conclusions are given. PMID:19053691

  12. Synthetic, structural and biological studies of organosilicon(IV complexes of Schiff bases derived from pyrrole-2-carboxaldehyde

    KIRAN SING

    2010-07-01

    Full Text Available Selected new organosilicon(IV complexes having the general formula R2SiCl[L] and R2Si[L] 2 were synthesized by the reactions of Me2SiCl2 with Schiff bases (5-mercapto-4-[(1H-pyrrol-2ylmethyleneamino]-s-triazole, 5-mercapto-3-methyl-4-[(1H-pyrrol-2ylmethyleneamino]-s-triazole and 3-ethyl-5-mercapto-4-[(1H-pyrrol-2ylmethyleneamino]-s-triazole in 1:1 and 1:2 molar ratios. All of the compounds were characterized by elemental analysis, molar conductance, and IR, UV, 1H-, 13C- and 29Si-NMR spectral studies. All the spectral data suggest an involvement with an azomethine nitrogen in coordination to the central silicon atom. With the help of above-mentioned spectral studies, penta and hexacoordinated environments around the central silicon atoms in the 1:1 and 1:2 complexes, respectively, are proposed. Finally, the free ligands and their metal complexes were tested in vitro against some pathogenic bacteria and fungi to assess their antimicrobial properties.

  13. Temperature dependence of dielectric properties of poly pyrrole composite films

    The composite polymer films of poly pyrrole-poly(vinyl alcohol)-iron chloride were prepared in the form of as-cast films. The dielectric properties of the samples were measured at the frequency range of 20 Hz to 1 MHz at different temperatures (300 K up to 353 K) by Inductance Capacitance Resistance (LCR) meter. The results show that the dielectric properties were strongly dependent on the variation of temperature applied. The composite polymer films exhibit the combination of intrinsic dielectric anisotropy, as a result of the competition of free charges, mainly between the polaron in poly pyrrole and the electronic polarisation that corresponded to PVA matrix. The main mechanism behind this finding can be explained by the dipole movement which highly activate at higher temperatures. In addition, high mobility of dipoles movement induced by thermal energy enables them to easily orient towards applied electric field. (author)

  14. Sensing of antipyretic carboxylates by simple chromogenic calix[4]pyrroles.

    Nishiyabu, Ryuhei; Anzenbacher, Pavel

    2005-06-15

    We present a simple, two- or three-step method for the synthesis of chromogenic octamethylcalix[4]pyrrole-based (OMCP) sensors for anions. Electrophilic aromatic substitution allows for converting the pyrrole moieties of OMCP into a dye. The formation of a sensor-anion complex results in partial charge transfer and a dramatic change in color. The absorption (UV-vis) and NMR titration experiments show that the chromogenic OMCPs sense anions administered as aqueous solutions, even at high ionic strength ( approximately 0.1 M NaCl), while displaying selectivity for pyrophosphate and carboxylate anions. The experiments with polyurethane sensor films show a strong response for aqueous carboxylates, such as antipyretics naproxen approximately ibuprofen > salicylate, without being biased by bicarbonate or carboxy termini of blood plasma proteins. PMID:15941245

  15. Asymmetrically substituted calix[4]pyrrole with chiral substituents

    Štěpánek, P.; Šimák, Ondřej; Nováková, Z.; Wimmer, Zdeněk; Drašar, P.

    2011-01-01

    Roč. 9, č. 3 (2011), s. 682-683. ISSN 1477-0520 R&D Projects: GA MŠk 2B06024 Grant ostatní: NATO(XE) CBP.EAP.CLG.982972 Institutional research plan: CEZ:AV0Z40550506; CEZ:AV0Z50380511 Keywords : porphyrin derivatives * anion-binding * aggregation * pyrrole * ketones Subject RIV: CC - Organic Chemistry Impact factor: 3.696, year: 2011

  16. Numerical Analysis Of Hooke Jeeves-Runge Kutta To Determine Reaction Rate Equation In Pyrrole Polymerization

    The numerical analysis of Hooke Jeeves Methods combined with Runge Kutta Methods is used to determine the exact model of reaction rate equation of pyrrole polymerization. Chemical polymerization of pyrrole was conducted with FeCI3 / pyrrole solution at concentration ratio of 1.62 mole / mole and 2.18 mole / mole with varrying temperature of 28, 40, 50, and 60 oC. FeCl3 acts as an oxidation agent to form pyrrole cation that will polymerize. The numerical analysis was done to examine the exact model of reaction rate equation which is derived from reaction equation of initiation, propagation, and termination. From its numerical analysis, it is found that the pyrrole polymerization follows third order of pyrrole cation concentration

  17. Multiphoton ionization of pyrrole-water mixed clusters

    2001-01-01

    Multiphoton ionization of the hydrogen-bonded pyrrole-water clusters ( C4H5 N)n H2O)m is studied with a reflectron—time of flight mass spectrometer at 355 nm. With increasing partial concentration of pyrrole in a gas mixture source, a series of poly-pyrrole-water binary-mixed cluster ions can be observed, including unprotonated cluster ions [(C4H5N)x (H2O)y]* , protonated cluster ions [(C4H5N)x (H2O)yH]* and dehydrogenated cluster ions [ ( C4 H4 N) ( C4 H5 N) x ( H2O) y ] + . Ab initio calculations of their structures, bond strengths, charge distributions and re action energies are carried out. Stable structures of these clusters are obtained from the calculations. A probable forma tion mechanism of the cluster ions [(C4H5N)x(H2O)y] + , [(C4H5N)x (H2O)y]H+ and [(C4H4N) (C4H5N)x (H2O)y]-is supposed to be the ionization of clusters followed by dissociation.

  18. Hydrazonoyl Chlorides as Precursors for Synthesis of Novel Bis-Pyrrole Derivatives

    Nabila Abdelshafy Kheder

    2016-03-01

    Full Text Available A convenient synthesis of some novel bis-pyrrole derivatives via hydrazonoyl halides is described. Antimicrobial evaluation of some selected examples of the synthesized products was carried out. The bis-pyrrole derivative having chloro substituents showed good activity against all of the used microbes. The molecular docking of the bis-pyrrole derivatives was performed by the Molecular Operating Environment (MOE program.

  19. Poly(pyrrole-co-pyrrole propylic acid) film and its application in label-free surface plasmon resonance immunosensors.

    Hu, Weihua; Li, Chang Ming; Dong, Hua

    2008-12-01

    In this work, surface plasmon resonance (SPR) was used to study protein immobilization on poly(pyrrole-co-pyrrole propylic acid) (PPy/PPa) for immunosensing applications. SPR was employed to in situ monitor the electropolymerization process and to control thickness of the PPy/PPa copolymer film. Goat IgG as a model protein was covalently immobilized on the carboxyl-containing film through EDC/NHS as the coupling reagents. The effect of pyrrole propylic acid (Pa) proportion in the deposition solution on the protein immobilization capability was systemically investigated. The immobilization efficiency was demonstrated by a label-free SPR immunosensor. The heterogeneous kinetics of the immune reaction was discussed. This work could provide a facile method to immobilize proteins on an electrode surface by electropolymerized copolymer, and renders a universal approach to in situ study the protein immobilization process and sensing kinetics for scientific insights of the heteroimmunosensing scheme particularly in surface chemistry and molecular biology for further improvement of immunosensors. PMID:19068327

  20. A novel quinoxaline bearing electroactive monomer: Pyrrole as the donor moiety

    Taskin, Asli Tuba; Balan, Abidin; Epik, Bugra; Yildiz, Ersin [Middle East Technical University, Department of Chemistry, 06531, Ankara (Turkey); Udum, Yasemin Arslan [Gazi University, Institute of Science and Technology, Department of Advanced Technologies, 06570, Ankara (Turkey); Toppare, Levent [Middle East Technical University, Department of Chemistry, 06531, Ankara (Turkey)], E-mail: toppare@metu.edu.tr

    2009-09-30

    A novel electroactive monomer 5,8-di(1H-pyrrol-2-yl)-2,3-di(thiophen-2-yl)quinoxaline (PTQ) was successfully synthesized and its electrochromic properties were reported. Nuclear magnetic resonance ({sup 1}H NMR-{sup 13}C NMR) and mass spectroscopy were used to characterize the monomer. The monomer was electrochemically polymerized in the presence of tetrabutylammonium perchlorate (TBAP) as supporting electrolyte in dichloromethane. Monomer reveals relatively low oxidation potential at +0.70 V. Spectroelectrochemical behaviors and switching ability of homopolymer were investigated by UV-vis spectroscopy and cyclic voltammetry. Two {pi}-{pi}* transitions were observed at 400 and 815 nm with a low band gap, 1.0 eV. Polymer possesses 66% optical contrast in the Near IR region, which may be promising in NIR electrochromic device applications.

  1. A novel quinoxaline bearing electroactive monomer: Pyrrole as the donor moiety

    A novel electroactive monomer 5,8-di(1H-pyrrol-2-yl)-2,3-di(thiophen-2-yl)quinoxaline (PTQ) was successfully synthesized and its electrochromic properties were reported. Nuclear magnetic resonance (1H NMR-13C NMR) and mass spectroscopy were used to characterize the monomer. The monomer was electrochemically polymerized in the presence of tetrabutylammonium perchlorate (TBAP) as supporting electrolyte in dichloromethane. Monomer reveals relatively low oxidation potential at +0.70 V. Spectroelectrochemical behaviors and switching ability of homopolymer were investigated by UV-vis spectroscopy and cyclic voltammetry. Two π-π* transitions were observed at 400 and 815 nm with a low band gap, 1.0 eV. Polymer possesses 66% optical contrast in the Near IR region, which may be promising in NIR electrochromic device applications.

  2. One-pot Green Synthesis of Pyrrole Derivatives Catalyzed by Nano Sulfated Zirconia as a Solid Acid Catalyst%One-pot Green Synthesis of Pyrrole Derivatives Catalyzed by Nano Sulfated Zirconia as a Solid Acid Catalyst

    Teimouri, Abbas; Chermahini, Alireza Najafi

    2012-01-01

    A new and efficient method for the preparation of N-substituted pyrroles from one-pot Paal-Knorr condensation has been accomplished using nano-crystalline sulfated zirconia (SZ) as the catalyst in ethanol at moderate temperature. This new protocol has the advantages of easy availability, stability, reusability and eco-friendliness of the catalyst, high to excellent yields, simple experimental and work-up procedure. The synthesized compounds were confirmed through spectral characterization using IR, 1H NMR, 13C NMR and mass spectra.

  3. A Novel TetraTTF-calix[4]pyrrole Ouroborand for Explosive Detection

    Bähring, Steffen; Nielsen, Kent

    We have synthesized the first example of an asymmetric tetraTTF-calix[4]pyrrole. This system features Ouroborand qualities due to selfcomplexation with the pyridine substituent. This forces the usually highly flexible calix[4]pyrrole into a preorganized conformation with improved explosive...

  4. Novel and efficient supramolecular synthesis of pyrroles in the presence of β-cyclodextrin in water

    K. Ramesh; K. Karnakar; G. Satish; Y.V.D. Nageswar

    2012-01-01

    A simple and efficient synthesis of highly substituted pyrroles was achieved in water medium via multi-component strategy,using amine,DMAD/DEAD as well as phenacyl bromide catalyzed by β-CD.Utilizing this protocol various pyrrole derivatives were synthesized in good to excellent yields.

  5. A Novel TetraTTF-calix[4]pyrrole Ouroborand for Explosive Detection

    Bähring, Steffen; Nielsen, Kent

    2010-01-01

    We have synthesized the first example of an asymmetric tetraTTF-calix[4]pyrrole. This system features Ouroborand qualities due to selfcomplexation with the pyridine substituent. This forces the usually highly flexible calix[4]pyrrole into a preorganized conformation with improved explosive...

  6. Interesting reactivity of diketones with pyrrole under acidic condition

    Sanjeev Pran Mahanta; Pradeepta Kumar Panda

    2011-09-01

    The acid catalysed condensation of diketones with pyrrole did not result in the formation of expected divergent bisdipyrromethane always; instead the product depends on the chain length of the diketones, in particular the distance between the two carbonyl functional groups.When the two carbonyl groups are linked via one or two methylene groups, unusual ring annulation occurs resulting in the formation of various bridged bipyrroles. However, on further increase in the length of the spacer, between the two carbonyl groups, synthesis of the expected bisdipyrromethanes could be achieved.

  7. Pyrrolic Amide: A New Hydrogen Bond Building Block for Self-assembly

    YIN Zhen-Ming; LI Jian-Feng; HE Jia-Qi; ZHU Xiao-Qing; CHENG Jin-Pei

    2003-01-01

    @@ Molecular self-assembly has emerged as a powerful technology for the synthesis of nanostructured materials. In design of various molecular assemblies, hydrogen bonding is a preferably selected intra- or inter-molecular weak interaction in recent research by virtue of the directionality and specificity. The research for novel hydrogen bond building blocks that self-assembly into well defined structures is great important not only for gaining an understanding of the concepts of self-assembly but also for the design of new molecular materials. Pyrrolic amide moiety has one hydrogen bond acceptor (C =O) and two hydrogen bond donors (pyrrole NH and amide NH). By deliberately design, pyrrolic amide compounds would be new kinds hydrogen bond building blocks. So, pyrrolic amide compounds 1 ~ 6, which bear one, two or three pyrrolic amide moieties respectively, were designed and synthesized.

  8. Eco-friendly synthesis, spectral and computational study of pyrrole-2-carboxaldehyde salicylhydrazone (PCSH) for its application

    Rawat, Poonam; Singh, R. N.

    2015-11-01

    In this paper we present eco-friendly synthesis of Pyrrole-2-carboxaldehyde salicylhydrazone (PCSH) and its molecular structural elucidation, spectral analysis and reactivity evaluation. Pyrrole-2-carboxaldehyde and salicyl hydrazide in water undergo condensation reaction to produce PCSH in good yield (88%). All results of quantum chemical calculation corroborate well with the experimental findings. The PCSH has been characterized by elemental analysis, FT-IR, 1H NMR, UV-Visible, and ESI-Mass spectroscopy. Density functional theory (DFT) calculations have been carried out for PCSH by performing B3LYP functional using the standard basis set 6-31 + g (d, p), and additional basis sets 6D and 10F. Two most stable conformers for PCSH have been observed around the dihedral angle N1C5C6N7. The red shift observed in O-H stretching vibration in the FT-IR spectrum indicates the presence of intramolecular hydrogen bonding. The rotational barrier between syn-syn (closed) syn-syn (open) found to be 2966.9 kcal/mol. The presence of hydroxyl proton at 10.45 ppm downfield in experimental 1H NMR spectrum confirms the existence of intramolecular hydrogen bonding in PCSH. Further, topological parameters analysis at the bond critical points using 'Atoms in molecules' theory reveals intramolecular hydrogen bonding. The energy of homonuclear intramolecular hydrogen bond (O17-H28⋯O10) is calculated to be 14.03 kcal/mol. The ellipticity results confirm the resonance assisted nature of this intramolecular hydrogen bond. In addition to this work, the reactive sites in PCSH have been explored using DFT descriptors, predicting nucleophilic reactions at carbonyl carbon and electrophilic reactions are possible at pyrrolic NH, amidic NH and double bond Cdbnd N leading to several heterocyclic products and metal complexes.

  9. Transition metal doped poly(aniline-co-pyrrole)/multi-walled carbon nanotubes nanocomposite for high performance supercapacitor electrode materials

    Dhibar, Saptarshi; Bhattacharya, Pallab; Hatui, Goutam; Das, C.K., E-mail: chapal12@yahoo.co.in

    2015-03-15

    Highlights: • The CuCl{sub 2} doped copolymer (PANI and PPy)/MWCNTs nanocomposite was prepared. • The nanocomposite achieved highest specific capacitance of 383 F/g at a 0.5 A/g. • Nanocomposite exhibits better energy density as well as power density. • The nanocomposite also showed better electrical conductivity at room temperature. • The nanocomposite can be used as promising electrode materials for supercapacitor. - Abstract: In this present communication, copolymer of polyaniline (PANI) and polypyrrole (PPy) that is poly(aniline-co-pyrrole) [poly(An-co-Py)], copper chloride (CuCl{sub 2}) doped poly(aniline-co-pyrrole) [poly(An-co-Py) Cu], and CuCl{sub 2} doped poly(aniline-co-pyrrole)/multi walled carbon nanotubes (MWCNTs) [poly(An-co-Py) Cu CNT] nanocomposite have been prepared by a simple and inexpensive in-situ chemical oxidative polymerization method, using ammonium persulfate (APS) as oxidant and hydrochloric acid (HCl) as dopant and investigated as high performance supercapacitor electrode materials. The possible interaction between CuCl{sub 2} with copolymers and MWCNTs was investigated by Fourier transform infrared spectroscopy (FTIR) and UV–visible spectroscopy analysis. The morphological characteristic of all the electrode materials were analyzed by Field emission scanning electron microscopy (FESEM) and Transmission electron microscopy (TEM) study. The electrochemical characterizations of all the electrode materials were carried out by three electrode probe method where, standard calomel electrode and platinum were used as reference and counter electrodes, respectively. Among all the electrode materials, poly(An-co-Py) Cu CNT nanocomposite achieved highest specific capacitance value of 383 F/g at 0.5 A/g scan rate. The nanocomposite showed better electrical conductivity at room temperature and also attained nonlinear current–voltage characteristic. Based on the superior electrochemical as well as other properties the as prepared

  10. Ferrocene-Functionalized 4-(2,5-Di(thiophen-2-yl-1H-pyrrol-1-ylaniline: A Novel Design in Conducting Polymer-Based Electrochemical Biosensors

    Rukiye Ayranci

    2015-01-01

    Full Text Available Herein, we report a novel ferrocenyldithiophosphonate functional conducting polymer and its use as an immobilization matrix in amperometric biosensor applications. Initially, 4-(2,5-di(thiophen-2-yl-1H-pyrrol-1-ylamidoferrocenyldithiophosphonate was synthesized and copolymerized with 4-(2,5-di(thiophen-2-yl-1H-pyrrol-1-ylbenzenamine at graphite electrodes. The amino groups on the polymer were utilized for covalent attachment of the enzyme glucose oxidase. Besides, ferrocene on the backbone was used as a redox mediator during the electrochemical measurements. Prior to the analytical characterization, optimization studies were carried out. The changes in current signals at +0.45 V were proportional to glucose concentration from 0.5 to 5.0 mM. Finally, the resulting biosensor was applied for glucose analysis in real samples and the data were compared with the spectrophotometric Trinder method.

  11. Electrochromic properties of multicolored novel polymer synthesized via combination of benzotriazole and N-functionalized 2,5-di(2-thienyl)-1H-pyrrole units

    Synthesis of new conducting polymers is desired since their electrochemical and optical properties enable them to be used as active layers in many device applications. Benzotriazole and N-functionalized 2,5-di(2-thienyl)-1H-pyrrole (SNS Series) containing polymers showed very promising results as electrochromic materials. In order to observe the effect of the combination of these two units, three new monomers; 2-(6-(2,5-bis(5-methylthiophen-2-yl)-1H-pyrrol-1-yl)hexyl)-4,7-di (thiophen-2-yl)-2H benzo[d][1,2,3]triazole (M1), 2-(6-(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl)hexyl)-4,7-di(thiophen-2-yl) -2H-benzo[d][1,2,3]triazole (M2) and 2-(6-(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl)hexyl)-4,7-bis (5-methylthiophen-2-yl)-2H-benzo[d][1,2,3]triazole (M3) were synthesized. To better characterize the electronic and spectroscopic properties of the monomers, density functional theory (DFT) and its time-dependent generalization (TD-DFT) were used to calculate their vertical ionization potentials, vertical electron affinity and to simulate and interpret their infrared and UV-vis spectra. The monomers were electrochemically polymerized and the resultant polymers were characterized with cyclic voltammetry and UV-vis-NIR spectroscopy techniques. An electrochromic device was constructed with electrochemical polymer of M2. The device switched between red and blue colors and showed exceptional optical memory

  12. Ru-catalyzed site-selective direct arylation polycondensation via ortho-metalation of pyrrole derivative

    A Ti-conjugated polymer consisting of pyrrole and fluorene units was synthesized via Ru-catalyzed direct arylation polycondensation. The introduction of a 2-pyrimidinyl substituent into the N -position of the pyrrole monomer as a directing group induced ortho-metalation, with effective site-selective polycondensation at the α-position of the pyrrole monomer, without the need for protection of the β-position. Subsequent removal of the 2-pyrimidinyl substituent led to the elongation of π-conjugation along the main chain of the polymer via elimination of the steric hindrance due to the bulky substituent

  13. 2-Ethyl 4-methyl 5-ethyl-3-methyl-1H-pyrrole-2,4-dicarboxylate

    Gui-Fen Lu

    2012-02-01

    Full Text Available The title pyrrole derivative compound, C12H17NO4, was synthesized from methyl 3-oxopentanoate by a Knorr-type reaction and contains a pyrrole ring to which two diagonal alkoxycarbonyl groups and two diagonal alkyl substituents are attached. The methylcarbonyl and ethylcarbonyl substituents are approximately co-planar with the pyrrole ring, making dihedral angles of 5.64 (2 and 3.44 (1°, respectively. In the crystal, adjacent molecules are assembled by pairs of N—H...O hydrogen bonds into dimers in a head-to-head mode.

  14. (4-Butoxyphenyl(1H-pyrrol-2-ylmethanone

    Rajni Kant

    2012-05-01

    Full Text Available The asymmetric unit of the title compound, C15H17NO2, contains two independent molecules in which the dihedral angles between the pyrrole and benzene rings are 42.43 (9 and 45.70 (9°. In both molecules, the butoxy chains are disordered over two sets of sites, with occupancy ratios of 0.701 (7:0.299 (7 and 0.869 (4:0.131 (4. Each molecule forms a dimer with an inversion-related molecule, through a pair of N—H...O hydrogen bonds. Weak C—H...O interactions link these dimers in the crystal structure.

  15. Discovery of pyrrole-based hepatoselective ligands as potent inhibitors of HMG-CoA reductase.

    Bratton, Larry D; Auerbach, Bruce; Choi, Chulho; Dillon, Lisa; Hanselman, Jeffrey C; Larsen, Scott D; Lu, Gina; Olsen, Karl; Pfefferkorn, Jeffrey A; Robertson, Andrew; Sekerke, Catherine; Trivedi, Bharat K; Unangst, Paul C

    2007-08-15

    In an effort to identify hepatoselective inhibitors of HMG-CoA reductase, two series of pyrroles were synthesized and evaluated. Efforts were made to modify (3R,5R)-7-[3-(4-fluorophenyl)-1-isopropyl-4-phenyl-5-phenylcarbamoyl-1H-pyrrol-2-yl]-3,5-dihydroxy-heptanoic acid sodium salt 30 in order to reduce its lipophilicity and therefore increase hepatoselectivity. Two strategies that were explored were replacement of the lipophilic 3-phenyl substituent with either a polar function (pyridyl series) or with lower alkyl substituents (lower alkyl series) and attachment of additional polar moieties at the 2-position of the pyrrole ring. One compound was identified to be both highly hepatoselective and active in vivo. We report the discovery, synthesis, and optimization of substituted pyrrole-based hepatoselective ligands as potent inhibitors of HMG-CoA reductase for reducing low density lipoprotein cholesterol (LDL-c) in the treatment of hypercholesterolemia. PMID:17560788

  16. Five gene products are required for assembly of the central pyrrole moiety of coumermycin A1

    Novotná, J.; Gust, B.; Kulik, A.; Spížek, Jaroslav; Heide, L.

    2013-01-01

    Roč. 40, č. 8 (2013), s. 915-925. ISSN 1367-5435 Institutional support: RVO:61388971 Keywords : Streptomyces * Coumermycin * Pyrrole Subject RIV: EE - Microbiology, Virology Impact factor: 2.505, year: 2013

  17. Auto-oligomerization and hydration of pyrrole revealed by x-ray absorption spectroscopy

    Advanced Light Source; Schwartz, Craig P.; Uejio, Janel S.; Duffin, Andrew M.; England, Alice H.; Prendergast, David; Saykally, Richard J

    2009-05-29

    Near edge x-ray absorption fine structure (NEXAFS) spectra have been measured at the carbon and nitrogen K-edges of the prototypical aromatic molecule, pyrrole, both in the gas phase and when solvated in water, and compared with spectra simulated using a combination of classical molecular dynamics and first principles density functional theory in the excited state core hole approximation. The excellent agreement enabled detailed assignments. Pyrrole is highly reactive, particularly in water, and reaction products formed by the auto-oligomerization of pyrrole are identified. The solvated spectra have been measured at two different temperatures, indicating that the final states remain largely unaffected by both hydration and temperature. This is somewhat unexpected, since the nitrogen in pyrrole can donate a hydrogen bond to water.

  18. Auto-oligomerization and hydration of pyrrole revealed by x-ray absorption spectroscopy

    Near edge x-ray absorption fine structure spectra have been measured at the carbon and nitrogen K-edges of the prototypical aromatic molecule, pyrrole, both in the gas phase and when solvated in water, and compared with spectra simulated using a combination of classical molecular dynamics and first principles density functional theory in the excited state core hole approximation. The excellent agreement enabled detailed assignments. Pyrrole is highly reactive, particularly in water, and reaction products formed by the auto-oligomerization of pyrrole are identified. The solvated spectra have been measured at two different temperatures, indicating that the final states remain largely unaffected by both hydration and temperature. This is somewhat unexpected, since the nitrogen in pyrrole can donate a hydrogen bond to water.

  19. Synthesis of new 2,5-dimethyl pyrrole derivatives from acetonylacetone

    Xiao Ming Ji; Ye Lu; Ming Qin Zhao; Xiao Yun Zhang; Yun Liu; Le Liu

    2010-01-01

    Acetonylacetone 1 was treated with thiourea, aniline, glycine and glutamic acid to give pyrrole derivatives 2, 3, 5, and 9 by Paal-Knorr reaction, respectively. Then 3 was successfully transformed into the related pyrrole derivative 4 by Mannich reaction.Compounds 6, 7 and 8 were obtained by reacting 5 with phenethyl alcohol, phenylallylic alcohol and leaf alcohol by esterification reactions, respectively. The structures of all new products were elucidated by IR, NMR and HRMS spectra.

  20. Facile synthesis, structural elucidation and spectral analysis of pyrrole 4-imidazole derivatives

    Singh, R. N.; Rawat, Poonam; Baboo, Vikas

    2015-12-01

    In this work pyrrole 4-imidazole derivatives (3A-3D): benzimidazoles and pyrrole 4-imidazoline have been synthesized by condensation, cyclization and oxidation of ethyl 4-formyl-3,5-dimethyl-1H-pyrrole carboxylate and phenylene diamine derivatives/ethylene diamine. The structure of these biheterocyclic compounds have been derived by elemental and spectroscopic - IR, UV, MS, 1H and 13C NMR analysis as well as theoretical study. The static first hyperpolarizability, β0 values for pyrrole 4-imidazole derivatives, (3A-3D) have been calculated as 10.901 × 10-31, 19.607 × 10-31, 40.323 × 10-31, 5.686 × 10-31 esu, respectively. The gradual increase in β0 value of synthesized pyrrole-benzimidazole derivatives from 3A to 3C is due to addition of acceptors -Cl atom in 3B to -NO2 group in 3C on benzimidazole side. The experimental absorption spectra found to be in UV region and the high β0 values show that the synthesized pyrrole-imidazoles are suitable as non-linear optical (NLO) materials.

  1. Energetics of 1-(aminophenyl)pyrroles: A joint calorimetric and computational study

    Santos, Ana Filipa L.O.M. [Centro de Investigacao em Quimica, Department of Chemistry and Biochemistry, Faculty of Science, University of Porto, Rua do Campo Alegre, 687, P-4169-007 Porto (Portugal); Ribeiro da Silva, Manuel A.V., E-mail: risilva@fc.up.pt [Centro de Investigacao em Quimica, Department of Chemistry and Biochemistry, Faculty of Science, University of Porto, Rua do Campo Alegre, 687, P-4169-007 Porto (Portugal)

    2011-10-15

    Highlights: > Enthalpy of formation of crystalline 1-(2-aminophenyl)pyrrole was determined by combustion calorimetry. > Vapor pressures of 1-(aminophenyl)pyrrole were measured as function of temperature by the Knudsen effusion technique. > Enthalpies of formation of the three gaseous isomers of 1-(aminophenyl)pyrrole were obtained by G3(MP2)//B3LYP calculations. - Abstract: Static bomb calorimetry and the Knudsen effusion mass-loss technique were used to derive, respectively, the standard (p{sup o} = 0.1 MPa) molar enthalpy of formation, in the crystalline phase, {Delta}{sub f}H{sub m}{sup 0}(cr), and the standard molar enthalpy of sublimation, at T = 298.15 K, {Delta}{sub cr}{sup g}H{sub m}{sup 0}, of 1-(2-aminophenyl)pyrrole. These experiments allowed the determination of its standard (p{sup o} = 0.1 MPa) molar enthalpy of formation, in the gaseous phase, {Delta}{sub f}H{sub m}{sup 0}(g), at T = 298.15 K, as (224.1 {+-} 2.4) kJ . mol{sup -1}. The gas-phase enthalpy of formation of 1-(2-aminophenyl)pyrrole was also estimated by G3(MP2)//B3LYP calculations, which were further extended to the (aminophenyl)pyrroles that were not studied experimentally. Experimental and theoretical results are in very good agreement.

  2. Synthesis of π-conjugated systems bearing thiophene and pyrrole heterocycles through palladium-catalyzed decarboxylative cross-coupling reaction

    Castro, M. Cidália R.; Fonseca, A. Maurício C.; Raposo, M. Manuela M.

    2012-01-01

    Thiophene and pyrrole moieties play important roles in synthetic and medicinal chemistry, as they are present in a large number of natural products and biologically active compounds. For this reason, amongst all five-membered aromatic heterocycles, molecules containing the pyrrole nucleus have attracted the greatest attention of researchers and have been studied in most detail. Especially, 2-aryl- and 2-heteroaryl-substituted pyrroles are of great interest to the pharmaceutical industry, for ...

  3. Hydrogen transfer in excited pyrrole-ammonia clusters

    David, O.; Dedonder-Lardeux, C.; Jouvet, C.; Kang, H.; Martrenchard, S.; Ebata, T.; Sobolewski, A. L.

    2004-06-01

    The excited state hydrogen atom transfer reaction (ESHT) has been studied in pyrrole-ammonia clusters [PyH-(NH3)n+hν→Py•+•NH4(NH3)n-1]. The reaction is clearly evidenced through two-color R2P1 experiments using delayed ionization and presents a threshold around 235 nm (5.3 eV). The cluster dynamics has also been explored by picosecond time scale experiments. The clusters decay in the 10-30 ps range with lifetimes increasing with the cluster size. The appearance times for the reaction products are similar to the decay times of the parent clusters. Evaporation processes are also observed in competition with the reaction, and the cluster lifetime after evaporation is estimated to be around 10 ns. The kinetic energy of the reaction products is fairly large and the energy distribution seems quasi mono kinetic. These experimental results rule out the hypothesis that the reaction proceeds through a direct N-H bond rupture but rather imply the existence of a fairly long-lived intermediate state. Calculations performed at the CASSCF/CASMP2 level confirm the experimental observations, and provide some hints regarding the reaction mechanism.

  4. 2-(4-Chloro-N-{2-[(1H-pyrrol-2-ylcarbonyloxy]ethyl}anilinoethyl 1H-pyrrole-2-carboxylate

    Ying Yan

    2012-02-01

    Full Text Available In the title molecule, C20H20ClN3O4, both the pyrrole N—H groups adopt a syn conformation with respect to the carbonyl groups. In the crystal, intermolecular N—H...O hydrogen bonds link the molecules into layers parallel to (102.

  5. Highly Sensitive Bisphenol-A Electrochemical Aptasensor Based on Poly(Pyrrole-Nitrilotriacetic Acid)-Aptamer Film.

    Kazane, Imen; Gorgy, Karine; Gondran, Chantal; Spinelli, Nicolas; Zazoua, Ali; Defrancq, E; Cosnier, Serge

    2016-07-19

    An electrochemical highly sensitive aptasensor was developed based on electropolymerized poly(pyrrole-nitrilotriacetic) acid film and a new aptamer functionalized by a pentahistidine peptide for the quantification of bisphenol A. A surface coverage of antibisphenol A aptamer of 1.84 × 10(-10) mol cm(-2) was estimated from the electrochemical signal of the [Ru(III)(NH3)6](3+) complex bound by electrostatic interactions onto the aptamer-modified electrode. The binding of bisphenol A onto the polymer film was successfully characterized by electrochemical methods as square wave voltammetry and electrochemical impedance spectroscopy measurements. The designed label-free impedimetric aptasensor displayed a wide linear range from 10(-11) to 10(-6) mol L(-1) with a sensitivity of 372 Ω per unit of log of concentration and an excellent specificity toward interfering agents such as 4,4'-dihydroxybiphenyl and bisphenol P. PMID:27332710

  6. Novel Octahydropyrrolo[3,4-c]pyrroles Are Selective Orexin-2 Antagonists: SAR Leading to a Clinical Candidate.

    Letavic, Michael A; Bonaventure, Pascal; Carruthers, Nicholas I; Dugovic, Christine; Koudriakova, Tatiana; Lord, Brian; Lovenberg, Timothy W; Ly, Kiev S; Mani, Neelakandha S; Nepomuceno, Diane; Pippel, Daniel J; Rizzolio, Michele; Shelton, Jonathan E; Shah, Chandra R; Shireman, Brock T; Young, Lana K; Yun, Sujin

    2015-07-23

    The preclinical characterization of novel octahydropyrrolo[3,4-c]pyrroles that are potent and selective orexin-2 antagonists is described. Optimization of physicochemical and DMPK properties led to the discovery of compounds with tissue distribution and duration of action suitable for evaluation in the treatment of primary insomnia. These selective orexin-2 antagonists are proven to promote sleep in rats, and this work ultimately led to the identification of a compound that progressed into human clinical trials for the treatment of primary insomnia. The synthesis, SAR, and optimization of the pharmacokinetic properties of this series of compounds as well as the identification of the clinical candidate, JNJ-42847922 (34), are described herein. PMID:26087021

  7. Synthesis of 2,2'-Dipyrryl Ketones from Pyrrole-2-carboxylic Acids with Trifluoroacetic Anhydride

    Kim, Se Hee; Lim, Jin Woo; Yu, Jin; Kim, Jae Nyoung [Chonnam National Univ., Gwangju (Korea, Republic of)

    2013-09-15

    An efficient synthesis of 2,2'-dipyrryl ketones has been carried out from pyrrole-2-carboxylic acids using trifluoroacetic anhydride (TFAA). Simultaneous generation of both mixed anhydride and 2-unsubstituted pyrrole, via facile decarboxylation with in-situ generated TFA, made their cross reaction (intermolecular Friedel-Crafts acylation) possible and efficient.

  8. A novel and facile approach for synthesis of 5-amino-7-aryl-6-cyano-4-pyrano[3,2-]pyrroles

    Reza Sandaroos; Saman Damavandi

    2012-07-01

    An efficient and iron-catalysed synthesis of 4-pyrano[3,2-]pyrrole is reported. The reactions proceed through a one-pot, three component cyclocondensation of 3-hydroxypyrrole, malononitrile and various aldehydes to afford 4-pyrano[3,2-]pyrrole derivatives in moderate to good yield using ferric hydrogensulphate, Fe(HSO4)3, as the catalyst.

  9. A copper-catalyzed coupling reaction of vinyl halides and carbazates: application in the assembly of polysubstituted pyrroles.

    Zhou, Chengang; Ma, Dawei

    2014-03-21

    CuI-catalyzed coupling of vinyl halides with carbazates gives N-protected N-alkenylhydrazines, which are condensed with ketones under acidic conditions to give polysubstituted pyrroles. The pyrrole synthesis may go through a similar mechanism with Fischer indole synthesis, which involves a [3,3]-sigmatropic rearrangement and other reactions. PMID:24514455

  10. Isolation and identification of a pyrrolic glutathione conjugate metabolite of the pyrrolizidine alkaloid monocrotaline.

    Lamé, M W; Morin, D; Jones, A D; Segall, H J; Wilson, D W

    1990-05-01

    This report describes the isolation and identification of a monocrotaline-derived, glutathione-conjugated pyrrole obtained from the bile of male Sprague-Dawley rats. Bile obtained from rats given an intravenous bolus of 14C-monocrotaline was fractionated using a series of chromatographic separations. Initial purification with cholestyramine resin removed bile acid and pigment contaminants. Subsequent anion exchange and reversed-phase HPLC separations yielded several fractions that contained the 14C label and tested positive for pyrroles using Ehrlich's reagent. These fractions were analyzed using fast-atom-bombardment tandem mass spectrometry (FAB MS/MS). In addition to glutathione-conjugated dehydroretronecine, at least one other pyrrole present had similar ionic properties. The latter was not present in amounts sufficient for positive identification. PMID:2111054

  11. Acetylcholinesterase-Inhibiting Activity of Pyrrole Derivatives from a Novel Marine Gliding Bacterium, Rapidithrix thailandica

    Khanit Suwanborirux; Anuchit Plubrukarn; Kornkanok Ingkaninan; Akkharawit Kanjana-opas; Supreeya Yuenyongsawad; Oraphan Sakulkeo; Yutthapong Sangnoi

    2008-01-01

    Acetylcholinesterase-inhibiting activity of marinoquinoline A (1), a new pyrroloquinoline from a novel species of a marine gliding bacterium Rapidithrix thailandica, was assessed (IC50 4.9 mM). Two related pyrrole derivatives, 3-(2'-aminophenyl)-pyrrole (3) and 2,2-dimethyl-pyrrolo-1,2-dihydroquinoline (4), were also isolated from two other strains of R. thailandica. The isolation of 3 froma natural source is reported here for the first time. Compound 4 was proposed to be an isolation artifac...

  12. Acetylcholinesterase-Inhibiting Activity of Pyrrole Derivatives from a Novel Marine Gliding Bacterium, Rapidithrix thailandica

    Sangnoi, Yutthapong; Sakulkeo, Oraphan; Yuenyongsawad, Supreeya; Kanjana-opas, Akkharawit; Ingkaninan, Kornkanok; Plubrukarn, Anuchit; Suwanborirux, Khanit

    2008-01-01

    Acetylcholinesterase-inhibiting activity of marinoquinoline A (1), a new pyrroloquinoline from a novel species of a marine gliding bacterium Rapidithrix thailandica, was assessed (IC50 4.9 μM). Two related pyrrole derivatives, 3-(2′-aminophenyl)-pyrrole (3) and 2,2-dimethyl-pyrrolo-1,2-dihydroquinoline (4), were also isolated from two other strains of R. thailandica. The isolation of 3 from a natural source is reported here for the first time. Compound 4 was proposed to be an isolation artifa...

  13. 2-[(E-(1H-Pyrrol-2-ylmethylidenehydrazinyl]pyridine monohydrate

    James L. Wardell

    2009-12-01

    Full Text Available The title hydrate, C10H10N4·H2O, shows a small twist in the hydrozone derivative, the dihedral angle between the pyridine and pyrrole rings being 11.08 (12°. The pyridine and pyrrole N atoms lie to the same side of the molecule being sustained in place by hydrogen-bonding interactions with the water molecule. Further intermolecular O—H...N and N—H...O hydrogen bonding leads to the formation of supramolecular arrays in the ab plane.

  14. Hydrolytic study of the copolymer Poly pyrrole/ Polyethyleneglycol and Poly pyrrole synthesized by plasma; Estudio hidrolitico del copolimero polipirrol/polietilenglicol y polipirrol sintetizado por plasma

    Colin, E.; Enriquez, M.A.; Olayo, M.G.; Cruz, G.J.; Carapia, L.; Romero, M. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico); Morales, J.; Olayo, R. [UAM-I, A.P. 55-534 Iztapalapa, Mexico D.F. (Mexico)

    2006-07-01

    In this work the study about the hydrolytic compatibility of semiconductor polymers, copolymer Poly pyrrole/ Polyethyleneglycol (PPy/PEG) and Poly pyrrole (PPy) for their possible use as biomaterials. The polymers were synthesized by plasma between 10 and 100 W, with discharges of splendor RF to 13.5 MHz with resistive coupling. The hydrolytic affinity was evaluated calculating the contact angle with solutions of NaCl, NaCl-MgSO{sub 4} and Krebs-Ringer. The results show a hydrophilicity increment due to the increase of the surface ruggedness with the synthesis energy. On the contrary, the crystallinity diminishes when increasing the power in PPy and it stays approximately constant in PPy/PEG. The electric conductivity presents a growth from 2 to 4 magnitude orders in function of the water content in the polymers. (Author)

  15. Label-free impedimetric biosensor for Salmonella Typhimurium detection based on poly [pyrrole-co-3-carboxyl-pyrrole] copolymer supported aptamer.

    Sheikhzadeh, E; Chamsaz, M; Turner, A P F; Jager, E W H; Beni, V

    2016-06-15

    The Gram-negative bacterium, Salmonella Typhimurium (S. Typhimurium) is a food borne pathogen responsible for numerous hospitalisations and deaths all over the world. Conventional detection methods for pathogens are time consuming and labour-intensive. Hence, there is considerable interest in faster and simpler detection methods. Polypyrrole-based polymers, due to their intrinsic chemical and electrical properties, have been demonstrated to be valuable candidates for the fabrication of chemo/biosensors and functional surfaces. Similarly aptamers have been shown to be good alternatives to antibodies in the development of affinity biosensors. In this study, we report on the combination of poly [pyrrole-co-3-carboxyl-pyrrole] copolymer and aptamer for the development of a label-less electrochemical biosensor suitable for the detection of S. Typhimurium. Impedimetric measurements were facilitated by the effect of the aptamer/target interaction on the intrinsic conjugation of the poly [pyrrole-co-3-carboxyl-pyrrole] copolymer and subsequently on its electrical properties. The aptasensor detected S. Typhimurium in the concentration range 10(2)-10(8)CFUmL(-1) with high selectivity over other model pathogens and with a limit of quantification (LOQ) of 100CFUmL(-1) and a limit of detection (LOD) of 3CFUmL(-1). The suitability of the aptasensor for real sample detection was demonstrated via recovery studies performed in spiked apple juice samples. We envisage this to be a viable approach for the inexpensive and rapid detection of pathogens in food, and possibly in other environmental samples. PMID:26836649

  16. A Facile Synthesis of Polysubstituted Pyrroles by One-Pot Three-Component Reaction

    Anaraki-Ardakani, Hossein; Noei, Maziar; Karbalaei-Harofteh, Mina; Zomorodbakhsh, Shahab

    2012-01-01

    A new and efficient one-pot synthesis of polysubstituted pyrrole derivatives by three-component reaction between dialkyl acetylenedicarboxylates, triphenylphosphine, 2-aminopyridin derivatives in the presence of arylglyoxals is described. The reactions were performed in dichloromethane at room temperature and neutral conditions and afforded high yields of products.

  17. Synthesis of Dihydropyrrolizine and Tetrahydroindolizine Scaffolds from Pyrroles by Titanocene(III) Catalysis.

    Hildebrandt, Sven; Gansäuer, Andreas

    2016-08-01

    A synthetic approach to dihydropyrrolizine and tetrahydroindolizine scaffolds from pyrroles has been developed. The key step, a titanocene(III)-catalyzed radical arylation that proceeds by C-H functionalization is atom-economical and tolerates a large variety of functional groups. The reaction is therefore attractive for the swift assembly of functional and structural diversity. PMID:27383638

  18. Clauson Kaas Pyrrole Synthesis Catalyzed by Acidic Ionic Liquid under Microwave Irradiation

    Cigdem Yolacan; Feray Aydogan

    2013-01-01

    A new procedure to synthesize the N-substituted pyrrole derivatives by Clauson Kaas reaction catalyzed by acidic ionic liquid under microwave irradiation was developed. This procedure provides several advantages such as high yield, clean product formation, and short reaction time.

  19. A C2-symmetric ratiometric fluorescence and colorimetric anion sensor based on pyrrole derivative

    A C2-symmetric fluorescence and colorimetric anion sensor (1) based on pyrrole derivative was designed and synthesized according to binding site-signaling subunit approach. The compound 1 was easily prepared by reaction of pyrrole-2,5-dicarboxaldehyde with 4-nitrophenylhydrazine in ethanol (yield=78%). In DMSO, the sensor 1 exhibited a visible color change from red to brown upon exposure to anions such as AcO- and F-; however, no obvious color changes were observed when the other tested anions (e. g. H2PO4-, Cl-, Br- and I-) were added. There was a significant redshift (Δλmax=160 nm) in UV-vis spectrum during UV-vis spectral titrations. In particular, the sensor 1 showed ratiometric fluorescence responses to anions. - Highlights: → C2-symmetric fluorescence and colorimetric anion sensor based on pyrrole derivative was designed and synthesized according to binding site-signaling subunit approach. → The sensor was easily prepared by reaction of pyrrole-2,5-dicarboxaldehyde with 4-nitrophenylhydrazine in ethanol (yield=78%). → In DMSO, the sensor exhibited a visible color change from red to brown upon exposure to anions such as AcO- and F-, however, no obvious color changes were observed when the other anions tested (e. g. H2PO4-, Cl-, Br- and I-) were added. → The sensor showed ratiometric fluorescence responses to anions.

  20. Self-Assembly of Dimeric Tetrathiafulvalene-Calix 4 pyrrole: Receptor for 1,375-Trinitrobenzene

    Nielsen, K. A.; Stein, P. C.

    2011-01-01

    The synthesis and binding properties of a tetrathiafulvalene (TTF)-calix[4]pyrrole receptor 2 appended with one 3,5-dinitrobenzoate guest moiety are reported. The preliminary studies revealed that the receptor is self-compiexing into a dimer receptor 2 center dot 2. The self-complexation of the...

  1. Identification of a new electron-transfer relaxation pathway in photoexcited pyrrole dimers

    Neville, Simon P.; Kirkby, Oliver M.; Kaltsoyannis, Nikolas; Worth, Graham A.; Fielding, Helen H.

    2016-04-01

    Photoinduced electron transfer is central to many biological processes and technological applications, such as the harvesting of solar energy and molecular electronics. The electron donor and acceptor units involved in electron transfer are often held in place by covalent bonds, π-π interactions or hydrogen bonds. Here, using time-resolved photoelectron spectroscopy and ab initio calculations, we reveal the existence of a new, low-energy, photoinduced electron-transfer mechanism in molecules held together by an NH⋯π bond. Specifically, we capture the electron-transfer process in a pyrrole dimer, from the excited π-system of the donor pyrrole to a Rydberg orbital localized on the N-atom of the acceptor pyrrole, mediated by an N-H stretch on the acceptor molecule. The resulting charge-transfer state is surprisingly long lived and leads to efficient electronic relaxation. We propose that this relaxation pathway plays an important role in biological and technological systems containing the pyrrole building block.

  2. Desorption and photopolymerization behavior of mixed and multilayered styrene-pyrrole nanofilms

    The molecular arrangement and polymerization of adsorbed styrene-pyrrole films were explored using two different dosing schemes: simultaneous dosing to form an intimately mixed film of the two monomers and sequential dosing to form films with distinct layers of styrene and pyrrole. It was found that the desorption of pyrrole was delayed until 175 K when either simultaneously dosed with styrene or in the presence of an overlying styrene layer, whereas it normally desorbs at 165 K when dosed alone. No such effects were observed with styrene in any dosing configuration. The polymerization rate of pyrrole was unaffected in the films when present as the top layer and was observed to decrease by 50% when beneath a styrene layer. Moreover, the rate of polymerization increased by two orders of magnitude in the case of the intimately mixed film. The rate of styrene polymerization was not found to change in any of the explored geometries. These effects are explained by considering the proximity of the components and the potential for screening UV radiation based on their molecular structure

  3. Non-adiabatic dynamics of pyrrole: Dependence of deactivation mechanisms on the excitation energy

    Barbatti, M.; Pittner, Jiří; Pederzoli, Marek; Werner, U.; Mitrić, R.; Bonačić-Koutecký, V.; Lischka, H.

    2010-01-01

    Roč. 375, č. 1 (2010), s. 26-34. ISSN 0301-0104 R&D Projects: GA AV ČR IAA400400810 Institutional research plan: CEZ:AV0Z40400503 Keywords : non-adiabatic dynamics * ultrafast phenomena * pyrrole Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.017, year: 2010

  4. Ferrocene-functionalized 4-(2,5-Di(thiophen-2-yl)-1H-pyrrol-1-yl)aniline: a novel design in conducting polymer-based electrochemical biosensors.

    Ayranci, Rukiye; Demirkol, Dilek Odaci; Ak, Metin; Timur, Suna

    2015-01-01

    Herein, we report a novel ferrocenyldithiophosphonate functional conducting polymer and its use as an immobilization matrix in amperometric biosensor applications. Initially, 4-(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl)amidoferrocenyldithiophosphonate was synthesized and copolymerized with 4-(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl)benzenamine at graphite electrodes. The amino groups on the polymer were utilized for covalent attachment of the enzyme glucose oxidase. Besides, ferrocene on the backbone was used as a redox mediator during the electrochemical measurements. Prior to the analytical characterization, optimization studies were carried out. The changes in current signals at +0.45 V were proportional to glucose concentration from 0.5 to 5.0 mM. Finally, the resulting biosensor was applied for glucose analysis in real samples and the data were compared with the spectrophotometric Trinder method. PMID:25591169

  5. Pyrrolo[3,2-b]pyrrole-Based Copolymers as Donor Materials for Organic Photovoltaics

    A new accepter unit, pyrrolo[3,2-b]pyrrole-2,5-dione, was prepared and utilized for the synthesis of the conjugated polymers containing electron donor-acceptor pair for OPVs. Pyrrolo[3,2-b]pyrrole-2,5-dione unit, regioisomer of the known pyrrolo[3,4-c]pyrrole-1,4-dione, is originated from the structure of stable synthetic pigment. The new conjugated polymers with 1,4-diphenylpyrrolo[3,2-b]pyrrole-2,5-dione, thiophene and carbazole were synthesized using Suzuki polymerization to generate P1 and P2. The solid films of P1 and P2 show absorption bands with maximum peaks at about 377, 554 and 374, 542 nm and the absorption onsets at 670 and 674 nm, corresponding to band gaps of 1.85 and 1.84 eV, respectively. To improve the hole mobility of the polymer with 1,4-bis(4-butylphenyl)-pyrrolo[3,2-b]-pyrrole-2,5-dione unit, which was previously reported by us, the butyl group at the 4-positions of the N-substituted phenyl group was substituted with hydrogen and methyl group. The field-effect hole mobility of P2 is 9.6 Χ 10-5 cm2/Vs. The device with P2:PC71BM (1:2) showed VOC value of 0.84 V, JSC value of 5.10 mA/cm2, and FF of 0.33, giving PCE of 1.42%

  6. A soluble conducting polymer of 2,5-di(thiophen-2-yl)-1-p-tolyl-1H-pyrrole and its electrochromic device

    A monomer 2,5-di(thiophen-2-yl)-1-p-tolyl-1H-pyrrole was synthesized via reaction of 1,4-di(2-thienyl)-1,4-butanedione and p-toluidine in the presence of catalytical amount of p-toluenesulfonic acid. Chemical polymerization of the monomer yielded a soluble polymer. The average molecular weight was determined by gel permeation chromatography as number average molecular weight (Mn) 2.5 x 103 g/mol. The monomer was also electrochemically polymerized in the presence of LiClO4, NaClO4 (1:1) as the supporting electrolyte in acetonitrile. Cyclic Voltammetry, Fourier Transform Infra Red, Nuclear Magnetic Resonance, Scanning Electron Microscopy and Ultraviolet-Visible Spectroscopy were employed for the characterization of the polymer. Spectroelectrochemistry analysis of homopolymer revealed an electronic transition at 428 nm which corresponds to π-π* transition. Switching ability of the homopolymer was evaluated by kinetic studies upon measuring the percent transmittance (%T) at the maximum contrast point, indicating that poly(2,5-di(thiophen-2-yl)-1-p-tolyl-1H-pyrrole) is a suitable material for electrochromic devices

  7. A new titanium biofunctionalized interface based on poly(pyrrole-3-acetic acid) coating: proliferation of osteoblast-like cells and future perspectives.

    De Giglio, Elvira; Cometa, Stefania; Calvano, Cosima-Damiana; Sabbatini, Luigia; Zambonin, Pier Giorgio; Colucci, Silvia; Benedetto, Adriana Di; Colaianni, Graziana

    2007-09-01

    In recent years, many procedures based on surface modification have been suggested to improve the biocompatibility and biofunctionality of orthopedic titanium-based implants. In this contest, the development of a new titanium-based biomaterial that could be covalently modified with biologically active molecules (i.e., RGD-peptides, growth factors, etc.) able to improve osteoblasts response was investigated. The strategy followed was based on a preliminary coating of the implant material by an adherent thin polymer film to which bioactive molecules could be grafted exploiting the polymer surface chemical reactivity. In this work, we focused our attention on pyrrole-3-acetic acid (Py-3-acetic), a pyrrole with carboxylic acid substituent, whose electrosynthesis and characterization on titanium substrates were already accomplished and whose potentialities in the design of new biocompatible surfaces are well evident. As first step, the biocompatibility of the electrochemically grown PPy-3-acetic films was investigated performing in vitro tests (adhesion and proliferation) with mouse bone marrow cells. Successively, the availability and reactivity of surface carboxylic groups were tested through the grafting of an aminoacidic residue to PPy-3-acetic films. PMID:17483896

  8. Preparation and evaluation of Pd/polymeric pyrrole-sodium lauryl sulfonate/foam-Ni electrode for 2,4-dichlorophenol dechlorination in aqueous solution

    Polymeric pyrrole-sodium lauryl sulfonate (PPy-SLS) composite film was applied to the preparation of palladium/foam-nickel (Pd/foam-Ni) electrode. The prepared Pd/PPy-SLS/foam-Ni electrode was characterized by cyclic voltammetry (CV), scanning electron microscope (SEM), X-ray diffraction (XRD), inductively coupled plasma-atomic emission spectroscopy (ICP-AES), and X-ray photoelectron spectroscopy (XPS). The addition of SLS improved the polymerization of pyrrole to form PPy-SLS film, which was conducive to prepare small Pd microparticles and led to the lower Pd loading, 0.85 mg cm−2. The composite electrode was used for electrochemically reductive dechlorination of 2,4-dichlorophenol (2,4-DCP) in aqueous solution. The influences of dechlorination current and initial pH value on the conversion efficiency and current the efficiency of 2,4-DCP dechlorination were studied. Complete dechlorination could be achieved on the Pd/PPy-SLS/foam-Ni electrode at ambient temperature under the condition of dechlorination current of 5 mA and initial pH value of 2.5 within 50 min. The electrode exhibits promising potential for dechlorination with high catalytic activity, good stability and low cost

  9. Biofabrication Using Pyrrole Electropolymerization for the Immobilization of Glucose Oxidase and Lactate Oxidase on Implanted Microfabricated Biotransducers

    Christian N. Kotanen

    2014-03-01

    Full Text Available The dual responsive Electrochemical Cell-on-a-Chip Microdisc Electrode Array (ECC MDEA 5037 is a recently developed electrochemical transducer for use in a wireless, implantable biosensor system for the continuous measurement of interstitial glucose and lactate. Fabrication of the biorecognition membrane via pyrrole electropolymerization and both in vitro and in vivo characterization of the resulting biotransducer is described. The influence of EDC-NHS covalent conjugation of glucose oxidase with 4-(3-pyrrolyl butyric acid (monomerization and with 4-sulfobenzoic acid (sulfonization on biosensor performance was examined. As the extent of enzyme conjugation was increased sensitivity decreased for monomerized enzymes but increased for sulfonized enzymes. Implanted biotransducers were examined in a Sprague-Dawley rat hemorrhage model. Resection after 4 h and subsequent in vitro re-characterization showed a decreased sensitivity from 0.68 (±0.40 to 0.22 (±0.17 µA·cm−2·mM−1, an increase in the limit of detection from 0.05 (±0.03 to 0.27 (±0.27 mM and a six-fold increase in the response time from 41 (±18 to 244 (±193 s. This evidence reconfirms the importance of biofouling at the bio-abio interface and the need for mitigation strategies to address the foreign body response.

  10. Use of Graphite Oxide and Graphene Oxide as Catalysts in the Synthesis of Dipyrromethane and Calix[4]pyrrole

    Sweta Mishra

    2011-08-01

    Full Text Available Graphite oxide and graphene oxides have been used as solid catalysts for the synthesis of 5,5-dialkyldipyrromethanes and calix[4]pyrroles in organic and aqueous solutions at room temperature.

  11. Direct Arylation of Pyrroles via Indirect Electroreductive C-H Functionalization Using Perylene Bisimide as an Electron-Transfer Mediator.

    Sun, Guoquan; Ren, Shuya; Zhu, Xinhai; Huang, Manna; Wan, Yiqian

    2016-02-01

    The indirect electroreductive coupling of aryl halides and pyrroles was successfully conducted using a catalytic amount of perylene bisimide as a mediator in 1-ethyl-3-methylimidazolium bis((trifluoromethyl)sulfonyl)imide ([EMIM]NTf2)/DMSO. PMID:26800089

  12. 3-/3,5-Pyrrole-substituted BODIPY derivatives and their photophysical and electrochemical studies

    KARTHIKA J KADASSERY; AKANKSHA NIMESH; SANOJ RAJ; NEERAJ AGARWAL

    2016-09-01

    Nucleophilic substitution on 3-bromo/3,5-dibromo-4,4'-difluoro-8-(aryl)-4-bora-3a,4a-diaza-sindacene (BODIPY), substituted with anisyl or thienyl at meso positions, with neat pyrrole afforded the mono and di-pyrrole substituted BODIPYs 1–4 in good yields. Large bathochromic shifts, upto ∼180 nm in absorption maxima (581–682 nm), and fluorescence maxima (606–695 nm) were observed for these BODIPYs. Absorption and fluorescence properties were studied in different solvents to compare the effect of mono and di substitution on BODIPY. The Lippert-Mataga equations were used which predict strong polarization of monosubstituted BODIPYs. Electrochemical studies were carried out to find the oxidation potential and HOMO energy levels were calculated. Theoretical studies of 1–4 provide the insight on the electron density distribution in 1–4. Theoretical and experimental photo-physical studies in different solvents were correlated to findthe substituent effects on BODIPY.

  13. The electropolymerization of pyrrole at a CuNi electrode: corrosion protection properties

    Fenelon, Anna M.; Breslin, Carmel B

    2003-12-01

    Pyrrole was successfully electropolymerized at a copper-nickel electrode in a near-neutral sodium oxalate solution containing Cu{sup 2+} cations to generate a homogenous and adherent polypyrrole film. The presence of the Cu{sup 2+} ions increased both the rate of the electropolymerization reaction and the adherence of the polymer at the CuNi interface. In the absence of these cations, oxidation of the electrode occurred generating a nickel-rich layer that was not sufficiently conducting, under the electropolymerization conditions employed, to facilitate the electron-transfer reaction and the electropolymerization of pyrrole. These films remained stable and exhibited significant corrosion protection properties in acidified and neutral 0.1 mol dm{sup -3} NaCl solutions even on polarization of the electrodes to high anodic potentials.

  14. New pentasubstituted pyrrole hybrid atorvastatin-quinoline derivatives with antiplasmodial activity.

    Carvalho, Rita C C; Martins, Wagner A; Silva, Tayara P; Kaiser, Carlos R; Bastos, Mônica M; Pinheiro, Luiz C S; Krettli, Antoniana U; Boechat, Núbia

    2016-04-15

    Cerebral malaria is caused by Plasmodium falciparum. Atorvastatin (AVA) is a pentasubstituted pyrrole, which has been tested as an adjuvant in the treatment of cerebral malaria. Herein, a new class of hybrids of AVA and aminoquinolines (primaquine and chloroquine derivatives) has been synthesized. The quinolinic moiety was connected to the pentasubstituted pyrrole from AVA by a linker group (CH2)n=2-4 units. The activity of the compounds increased with the size of the carbons chain. Compound with n=4 and 7-chloroquinolinyl has displayed better activity (IC50=0.40μM) than chloroquine. The primaquine derivative showed IC50=1.41μM, being less toxic and more active than primaquine. PMID:26988303

  15. Dichloridobis(4-pyridylmethyl 1H-pyrrole-2-carboxylate-κNzinc

    Guilong Zhang

    2012-03-01

    Full Text Available In the title molecule, [ZnCl2(C11H10N2O22], the ZnII ion, situated on a twofold axis, is in a distorted tetrahedral coordination environment formed by two chloride anions and two pyridine N atoms of the two organic ligands. In the pyrrole-2-carboxylate unit, the pyrrole N—H group and the carbonyl group point approximately in the same direction. The dihedral angle between the two pyridine rings is 54.8 (3°. The complex molecules are connected into chains extending along [101] by N—H...Cl hydrogen bonds. The chains are further assembled into (-101 layers by C—H...O and C—H...Cl interactions.

  16. 2-(2-hydroxyethyl)-1H,3H-benzo[c]pyrrol-1-one

    Urban, Jiří; Fábry, Jan; Zuman, P.; Ludvík, Jiří; Císařová, I.

    2007-01-01

    Roč. 63, - (2007), o4137-o4138. ISSN 1600-5368 R&D Projects: GA MŠk 1P05ME785 Institutional research plan: CEZ:AV0Z40400503; CEZ:AV0Z10100520 Keywords : 2-(2-hydroxyethyl)-1H,3H-benzo[c]pyrrol-1-one * hydrogen bonds * interactions Subject RIV: CG - Electrochemistry Impact factor: 0.508, year: 2007

  17. A joint experimental and computational investigation on the thermochemistry of (nitrophenyl)pyrroles

    Santos, Ana Filipa L.O.M. [Centro de Investigacao em Quimica, Department of Chemistry, Faculty of Science, University of Porto, Rua do Campo Alegre, 687, P-4169-007 Porto (Portugal); Ribeiro da Silva, Manuel A.V., E-mail: risilva@fc.up.p [Centro de Investigacao em Quimica, Department of Chemistry, Faculty of Science, University of Porto, Rua do Campo Alegre, 687, P-4169-007 Porto (Portugal)

    2010-08-15

    This paper reports the standard (p{sup o} = 0.1 MPa) molar enthalpies of formation, in the gaseous phase, {Delta}{sub f}H{sub m}{sup 0}(g), at T = 298.15 K, of 1-(2-nitrophenyl)pyrrole and of 1-(4-nitrophenyl)pyrrole as (235.7 {+-} 2.7) kJ . mol{sup -1} and (205.5 {+-} 2.5) kJ . mol{sup -1}, respectively. These values were derived from experimental thermodynamic parameters, namely from the standard (p{sup o} = 0.1 MPa) molar enthalpies of formation, in the crystalline phase, {Delta}{sub f}H{sub m}{sup 0}(cr), at T = 298.15 K, obtained from the standard molar enthalpies of combustion, {Delta}{sub c}H{sub m}{sup 0}, measured by static-bomb combustion calorimetry, and from the standard molar enthalpies of sublimation, at T = 298.15 K, determined from the temperature-vapour pressure dependence, obtained by the Knudsen mass loss effusion method. Additionally, the gas-phase enthalpies of formation were estimated by G3(MP2)//B3LYP calculations, using several gas-phase working reactions, and were compared with the experimental determined ones. Experimental and theoretical results are in very good agreement and show that 1-(4-nitrophenyl)pyrrole is thermodynamically more stable than the 2-isomer. This composite approach was also used to estimate the gas-phase enthalpy of formation of the 1-(3-nitrophenyl)pyrrole.

  18. Design and synthesis of hepatoselective, pyrrole-based HMG-CoA reductase inhibitors.

    Pfefferkorn, Jeffrey A; Song, Yuntao; Sun, Kuai-Lin; Miller, Steven R; Trivedi, Bharat K; Choi, Chulho; Sorenson, Roderick J; Bratton, Larry D; Unangst, Paul C; Larsen, Scott D; Poel, Toni-Jo; Cheng, Xue-Min; Lee, Chitase; Erasga, Noe; Auerbach, Bruce; Askew, Valerie; Dillon, Lisa; Hanselman, Jeffrey C; Lin, Zhiwu; Lu, Gina; Robertson, Andrew; Olsen, Karl; Mertz, Thomas; Sekerke, Catherine; Pavlovsky, Alexander; Harris, Melissa S; Bainbridge, Graeme; Caspers, Nicole; Chen, Huifen; Eberstadt, Matthias

    2007-08-15

    This manuscript describes the design and synthesis of a series of pyrrole-based inhibitors of HMG-CoA reductase for the treatment of hypercholesterolemia. Analogs were optimized using structure-based design and physical property considerations resulting in the identification of 44, a hepatoselective HMG-CoA reductase inhibitor with excellent acute and chronic efficacy in a pre-clinical animal models. PMID:17574412

  19. Pyrrole Azocrown Ethers. Synthesis, Complexation, Selective Lead Transport and Ion-Selective Membrane Electrode Studies

    Luboch, Elzbieta; Wagner-Wysiecka, Ewa; Fainerman-Melnikova, Marina; Lindoy, Leonard F.; Biernat, Jan F.

    2006-01-01

    Abstract New 21-membered lipophilic crown ethers, each incorporating a pyrrole unit and two azo groups as macrocyclic ring components, have been synthesized. The complexation behavior of these and two further macrocycles has been investigated in acetonitrile. These ligand systems have been employed as ionophores in transport experiments involving the competitive transport behavior of an equimolar mixture of Co2+, Ni2+, Cu2+, Zn2+, Cd2+, Ag+ and Pb2+ across a water (pH 4.9)/chlorof...

  20. tert-Butyl 2-borono-1H-pyrrole-1-carboxylate

    Zheng Zhong

    2009-04-01

    Full Text Available In the crystal structure of the title compound, C9H14BNO4, the boronic acid group and carbamate groups are nearly co-planar with the pyrrole ring, making dihedral angles of 0.1 (2 and 2.2 (2°, respectively. Intramolecular and intermolecular O—H...O hydrogen bonds help to stabilize the structure, the latter interaction leading to inversion dimers..

  1. Interaction of derived polymers from pyrrole with biocompatible solutions; Interaccion de polimeros derivados de pirrol con soluciones biocompatibles

    Lopez G, O. G.

    2010-07-01

    This work presents a study about the synthesis by plasma, the electric properties and superficial interaction of polymers derived from pyrrole doped with Iodine with potential use as bio material. Poly-pyrrole is a semiconductor and biocompatible polymer with potential application in the development of artificial muscles and implants where the electric interaction between cells and material is an important variable. The syntheses were made at 13.5 MHz in a glass tubular reactor of 1500 cm{sup 3} with electrodes of 6.5 cm diameter and stainless steel flanges. An electrode was connected to the RF terminal of the power supply that is combined with a matching coupling resistance. The monomer and dopant used in this work were pyrrole and Iodine respectively, in closed containers. They were vaporized and injected separately into the reactor at room temperature and 0.1 mbar. The vapors of the reagents mixed freely in the reactor. The synthesis time was 240 min at 40, 60, 80 and 100 W. The polymers were obtained as thin films adhered to the reactor walls. The films were washed and swollen with distilled water and removed from the reactor walls with a small spatula. The polymers were irradiated with gamma rays at 18 and 22 KGy. Due to the fact that the doses are cumulative, the final dose applied was 40 KGy. The polymers characterization was carried out by Fourier Transform Infrared Spectroscopy, thermogravimetric analysis (TGA), scanning electron microscopy, contact angle, electrical conductivity and X-ray diffraction. The analyses indicates that the polymers have very similar structure in almost the entire power range, showing C-O, C=C, C-H, O-H, N-H bonds with a predominantly amorphous structure. The TGA analyses showed that the material has 4 or 5 loses of material. The first one starts after that 115 C except for the material irradiated at 40 KGy, this one begins in 87 C, the second one is in the interval of 196 and 295 C, the third one between 311 and 500 C, and the

  2. Electrodeposition of (pyrrole-co-phenol) on steel surfaces in mixed electrolytes of oxalic acid and DBSA

    Poly (pyrrole-co-phenol) (co-PyPh) was synthesised using cyclic voltammetry in the mixture of dodecyl benzene sulphonic acid (DBSA) with oxalic acid solution on steel electrodes. The morphology and compositions were characterized by Field Emission Scanning Electron Microscopy (FESEM), Fourier Transform Infrared Spectroscopy (FTIR) techniques and Energy-dispersive X-ray spectroscopy (EDX). Electrode/co-PyPh/electrolyte system was studied in 0.1 M NaCl solutions by Electrochemical Impedance Spectroscopy (EIS). The Warburg impedance observed in mid frequency region is an evidence of the effective barrier behaviour of coating. The results of EDX indicate that the content of doped sulphur can influence the morphology of co-PyPh. Three dissimilar morphologies of co-PyPh and different amount of doped sulphur in co-PyPh are observed. The existence of phenol monomer leads to a decrease in the amount of doped sulphur in co-PyPh compared with synthesised polypyrrole (PPy) in the same environment.

  3. A soluble conducting polymer: 1-Phenyl-2,5-di(2-thienyl)-1H-pyrrole and its electrochromic application

    Tarkuc, S. [Department of Chemistry, Middle East Technical University, 06531 Ankara (Turkey); Sahmetlioglu, E. [Department of Chemistry, Middle East Technical University, 06531 Ankara (Turkey); Department of Chemistry, Nigde University, 51100 Nigde (Turkey); Tanyeli, C. [Department of Chemistry, Middle East Technical University, 06531 Ankara (Turkey); Akhmedov, I.M. [Department of Chemistry, Middle East Technical University, 06531 Ankara (Turkey); Toppare, L. [Department of Chemistry, Middle East Technical University, 06531 Ankara (Turkey)]. E-mail: toppare@metu.edu.tr

    2006-07-28

    A thiophene-functionalized monomer 1-phenyl-2,5-di(2-thienyl)-1H-pyrrole (PTP) was synthesized. The chemical polymerization of PTP (CPTP) was realized by using FeCl{sub 3} as the oxidant. The structures of both the monomer and the soluble polymer (CPTP) were investigated by Nuclear Magnetic Resonance ({sup 1}H and {sup 13}C NMR) and Fourier Transform Infrared (FTIR). The average molecular weight of the chemically synthesized polymer was determined by gel permeation chromatography (GPC) as Mn = 7.2 x 10{sup 3}. The electrochemical oxidative polymerization of PTP was carried out via constant-potential electrolysis. Characterizations of the resulting polymer were done by cyclic voltammetry (CV), FTIR, Scanning Electron Microscopy (SEM) and UV-vis Spectroscopy. The conductivity of sample was measured by four-probe technique. Moreover, the spectroelectrochemical and electrochromic properties of the polymer film were investigated. Spectroelectrochemical analysis of P(PTP) revealed electronic transitions at 413, 577 and 884 nm corresponding to {pi}-{pi}* transition, polaron, and bipolaron band formations, respectively. Kinetic studies evaluated the switching ability of the P(PTP); the percent transmittance T% was found as 27%. The homopolymer of PTP was used to construct dual-type polymer electrochromic devices (ECDs) against poly(3,4-ethylenedioxythiophene) (PEDOT). Spectroelectrochemistry, electrochromic switching and open circuit stability of the devices were investiga0009t.

  4. A soluble conducting polymer: 1-Phenyl-2,5-di(2-thienyl)-1H-pyrrole and its electrochromic application

    A thiophene-functionalized monomer 1-phenyl-2,5-di(2-thienyl)-1H-pyrrole (PTP) was synthesized. The chemical polymerization of PTP (CPTP) was realized by using FeCl3 as the oxidant. The structures of both the monomer and the soluble polymer (CPTP) were investigated by Nuclear Magnetic Resonance (1H and 13C NMR) and Fourier Transform Infrared (FTIR). The average molecular weight of the chemically synthesized polymer was determined by gel permeation chromatography (GPC) as Mn = 7.2 x 103. The electrochemical oxidative polymerization of PTP was carried out via constant-potential electrolysis. Characterizations of the resulting polymer were done by cyclic voltammetry (CV), FTIR, Scanning Electron Microscopy (SEM) and UV-vis Spectroscopy. The conductivity of sample was measured by four-probe technique. Moreover, the spectroelectrochemical and electrochromic properties of the polymer film were investigated. Spectroelectrochemical analysis of P(PTP) revealed electronic transitions at 413, 577 and 884 nm corresponding to π-π* transition, polaron, and bipolaron band formations, respectively. Kinetic studies evaluated the switching ability of the P(PTP); the percent transmittance T% was found as 27%. The homopolymer of PTP was used to construct dual-type polymer electrochromic devices (ECDs) against poly(3,4-ethylenedioxythiophene) (PEDOT). Spectroelectrochemistry, electrochromic switching and open circuit stability of the devices were investigated

  5. Preparation of thin α-particle sources using poly-pyrrole films functionalized by a chelating agent

    This work takes place in the scope of analysis of the α-particle emitting elements U, Pu and Am present in compound environmental matrix like sols and sediments. The samples diversity and above all the α-ray characteristics require the analyst to implement a sequence of chemical steps in which the more restricting is the actinides concentration in a uniform and thin layer en allowing an accurately measure of alpha activity. On this account, we studied a new technique for radioactive sources preparation based on tow steps: preparation of a thin film as source support; incorporation of radioactive elements by a chelating extraction mechanism. The thin films were obtained through electro-polymerization of pyrrole monomer functionalized by an chelating ligand able to extract actinides from concentrated acidic solutions. Polymerization conditions of this monomer were perfected, then obtained films were characterized from a physico-chemical point of view. We point out their extracting properties were comparable to (retention capacity, distribution coefficient) to those of usual ion-exchange resins. The underscore of uranyl and americium nitrate complexes formed in the thin layer allowed to calculate the extraction constants in case acid extraction is negligible. Thanks to this results, the values of the coefficients distribution DU and DAm could be provided for all nitric solutions in which acid extraction is negligible. Optimal actinides retention conditions in the polymer were defined and used to settle a protocol for plutonium analysis in environmental samples. (author)

  6. Electrochromic and electrochemical properties of 3-pyridinyl and 1,10-phenanthroline bearing poly(2,5-di(2-thienyl)-1H-pyrrole) derivatives

    Hwang, Jaeyoung; Ik Son, Jung; Shim, Yoon-Bo [Department of Chemistry, Pusan National University, Keumjeong-ku, Busan 609-735 (Korea)

    2010-07-15

    This study examined a highly efficient synthetic route and characterization of two derivatives of 2,5-di(2-thienyl)-1H-pyrrole that incorporated 3-pyridinyl and 1,10-phenanthroline moieties in the central pyrrole ring. The electrically conductive polyPTPy and polyPhenTPy films were synthesized through electropolymerization on a glassy carbon electrode in a 0.1 M TBAP/dichloromethane solution. The polymer films were characterized using cyclic voltammetry (CV), in situ conductivity measurements, and in situ spectroelectrochemistry. The redox peaks of the polyPTPy and polyPhenTPy films were observed at 0.96/0.66 and 0.89/0.73 V, respectively. The maximum conductivities of polyPTPy and polyPhenTPy were 6.5 x 10{sup -2} and 9.2 x 10{sup -2} S/cm at 1.4 V. The spectroelectrochemical analysis showed that the polyPTPy film was brownish-yellow color ({lambda}{sub max}=430 nm) in the neutral state and dark blue (1.4 V) in the fully oxidized state. Similarly, polyPhenTPy was greenish-yellow color ({lambda}{sub max}=451 nm) in the neutral state and light blue (1.4 V) in the fully oxidized state. The polymer films exhibited a fast optical switching time within 1.0 s. The electrochemical and spectroelectrochemical characterizations of these films revealed that the materials were highly electroactive and robust in terms of electrochromics. (author)

  7. Spectral, IR and magnetic studies of Mn(II), Co(II), Ni(II) and Cu(II) complexes with pyrrole-2-carboxyaldehyde thiosemicarbazone (L)

    Chandra, Sulekh; Kumar, Anil

    2007-11-01

    Mn(II), Co(II), Ni(II) and Cu(II) complexes are synthesized with thiosemicarbazone (L) derived from pyrrole-2-carboxyaldehyde. These complexes are characterized by elemental analysis, molar conductance, magnetic susceptibility measurement, mass, IR, electronic and EPR spectral studies. The molar conductance measurement of the complexes in DMSO indicates that the complexes are non-electrolyte except Co(L) 2(NO 3) 2 and Ni(L) 2(NO 3) 2 complexes which are 1:2 electrolyte. All the complexes are of high-spin type. On the basis of spectral studies an octahedral geometry may be assigned for Mn(II), Co(II) and Ni(II) complexes except Co(L) 2(NO 3) 2 and Ni(L) 2(NO 3) 2 which are of tetrahedral geometry. A tetragonal geometry may be suggested for Cu(II) complexes.

  8. Biological activity of two new pyrrole derivatives against stored-product species: influence of temperature and relative humidity.

    Boukouvala, M C; Kavallieratos, N G; Athanassiou, C G; Hadjiarapoglou, L P

    2016-08-01

    Members of the pyrrole group are likely to have interesting properties that merit additional investigation as insecticides at the post-harvest stages of agricultural commodities. In the present work, the insecticidal effect of two new pyrrole derivatives, ethyl 3-(benzylthio)-4,6-dioxo-5-phenyl-2,4,5,6-tetrahydropyrrolo[3,4-c]pyrrole-carboxylate (3i) and isopropyl 3-(benzylthio)-4,6-dioxo-5-phenyl-2,4,5,6-tetrahydropyrrolo[3,4-c]pyrrole-carboxylate (3k) were studied as stored-wheat protectants against two major stored-product insect species, the confused flour beetle, Tribolium confusum Jaquelin du Val adults and larvae and the Mediterranean flour moth, Ephestia kuehniella Zeller larvae at different doses (0.1, 1 and 10 ppm), exposure intervals (7, 14 and 21 days), temperatures (20, 25 and 30°C) and relative humidity (55 and 75%) levels. For T. confusum adults, in the case of the pyrrole derivative 3i, mortality was low and it did not exceed 32.2% in wheat treated with 10 ppm 3i at 30°C and 55% relative humidity. Progeny production was very low (insecticidal effect, but this effect is moderated by the exposure, the target species, the temperature and the relative humidity. PMID:27087458

  9. Electrochemical polymerization of pyrrole over AZ31 Mg alloy for biomedical applications

    Highlights: ► Polymerization of pyrrole over AZ31 Mg was carried out using cyclic voltammetry. ► Pyrrole concentration was optimized to accomplish the adherent and uniform coating. ► Effect of monomer concentration on the surface morphology was discussed. ► Corrosion resistance of AZ31 Mg in SBF was studied as a function of Py concentration. ► PPy coated AZ31 Mg alloy exhibited enhanced corrosion resistance at 0.25 M of Py. -- Abstract: Electrochemical polymerization of pyrrole (Py) from aqueous salicylate solution over AZ31 Mg alloy was carried out using cyclic voltammetry (CV). The effect of monomer concentration on the surface and electrochemical corrosion in simulated body fluid (SBF) were analysed. Attenuated total reflection-infrared (ATR-IR) spectra showed the characteristic ring stretching peaks for polypyrrole (PPy). Scanning electron microscopy (SEM) and atomic force microscopy (AFM) studies exhibited typical cauliflower morphology with rough surface for PPy coated AZ31 Mg alloy. Open circuit potential measurement and potentiodynamic polarization studies revealed that the coating prepared using 0.25 M of Py had positive shift of about 120 mV in corrosion potential and lower corrosion current density (0.03 mA/cm2) compared to other concentrations and uncoated AZ31 Mg alloy (0.25 mA/cm2). Electrochemical impedance spectroscopic (EIS) studies of uncoated and PPy coated Mg alloy in SBF revealed three-time constants behaviour with about one order of increment in impedance value for 0.25 M of Py

  10. Quantification of CH-π Interactions Using Calix[4]pyrrole Receptors as Model Systems

    Gemma Aragay

    2015-09-01

    Full Text Available We describe the use of two series of aryl-extended calix[4]pyrrole receptors bearing two and four electronically tunable phenyl groups, respectively, in their meso-positions as model systems for the quantification of CH-π interactions in solution. The “four-wall” and the “two-wall” receptors formed thermodynamically stable 1:1 complexes in acetonitrile solution with both trimethylamine N-oxide and trimethylphosphine P-oxide as guests. The complexes were mainly stabilized by the formation of four convergent hydrogen bonds between the oxygen atom of the guests and the pyrrole NHs of the host. In general, the N-oxide produced thermodynamically more stable hydrogen bonding interactions than the P-oxide. Upon guest binding, the receptors adopted the cone conformation and the methyl groups of the included guests engaged in CH-π interactions with the aromatic walls. We show that the modification of the electronic properties of the aromatic surfaces, in any of the receptor series, did not have a significant impact in the measured binding affinities for a given guest. However, the larger binding affinities determined for the “four-wall” receptors in comparison to the “two-wall” counterparts supported the importance of CH-π interactions on guest complexation. The strength of the CH-π interactions present in the inclusion complexes was quantified employing the octamethyl calix[4]pyrrole as reference. We determined an average magnitude of ~1 kcal·mol−1 for each CH-π interaction. The CH-π interactions featured a reduced electrostatic nature and thus dispersion forces were assigned as main contributors of their strength.

  11. Sustainable Pathways to Pyrroles through Iron-Catalyzed N-Heterocyclization from Unsaturated Diols and Primary Amines.

    Yan, Tao; Barta, Katalin

    2016-09-01

    Pyrroles are prominent scaffolds in pharmaceutically active compounds and play an important role in medicinal chemistry. Therefore, the development of new, atom-economic, and sustainable catalytic strategies to obtain these moieties is highly desired. Direct catalytic pathways that utilize readily available alcohol substrates have been recently established; however, these approaches rely on the use of noble metals such as ruthenium or iridium. Here, we report on the direct synthesis of pyrroles using a catalyst based on the earth-abundant and inexpensive iron. The method uses 2-butyne-1,4-diol or 2-butene-1,4-diol that can be directly coupled with anilines, benzyl amines, and aliphatic amines to obtain a variety of N-substituted pyrroles in moderate-to-excellent isolated yields. PMID:27493031

  12. Gliclazide impurity F: N-[(perhydrocyclopenta[c]pyrrol-2-ylaminocarbonyl]-o-toluenesulfonamide

    Di Wu

    2012-02-01

    Full Text Available The title compound, C15H21N3O3S, is known to be an impurity of gliclazide [systematic name: N-(hexahydro-1H-cyclopenta[c]pyrrol-2-ylcarbamoyl-4-methylbenzenesulfonamide], a sulfonylurea antidiabetic drug. Gliclazide has a p-tolyl group substituting the sulfonamide functionality, while the title molecule contains an o-tolyl group. Both five-membered fused rings adopt envelope conformations. In the crystal, N—H...O hydrogen bonds are formed between HN(C=ONH groups, building centrosymmetric dimers. These dimers are further linked through N—H...O(sulfonyl contacts, forming chains in [100].

  13. Low frequency ac conduction and dielectric relaxation in poly(N-methyl pyrrole)

    Amarjeet K Narula; Ramadhar Singh; Subhas Chandra

    2000-06-01

    The ac conductivity and dielectric constant of poly(N-methyl pyrrole) thin films have been investigated in the temperature range 77–350 K and in the frequency range 102–106 Hz. The well defined loss peaks have been observed in the temperature region where measured ac conductivity approaches dc conductivity. These loss peaks are associated with the hopping of the charge carriers. The frequency and temperature dependence of ac conductivity have been qualitatively explained by considering the contribution from two mechanisms; one giving a linear dependence of conductivity on frequency and other having distribution of relaxation times giving rise to broad dielectric loss peak.

  14. Thermal Diffusivity Measurement of Poly pyrrole-Chitosan Composite by Photoacoustic Technique

    Thermal diffusivity is a physical quantity that represents an intrinsic property for a material and indicates how fast heat propagates through a sample. The photoacoustic (PA) technique has recently been recognized as a powerful and reliable experimental technique in measuring thermal diffusivity. This effect is described as the periodic heating generated in the sample by a nonradiative deexcitation process due to the absorption of a modulated light source [1]. In present work, the conducting polymer composite films of poly pyrrole-chitosan (PPy- CHI) were synthesized by electrochemical polymerization method. The electrical conductivity and thermal diffusivity of composite film were studied as a function of electro polymerization conditions. (author)

  15. Biosynthesis, asymmetric synthesis, and pharmacology, including cellular targets, of the pyrrole-2-aminoimidazole marine alkaloids

    Al-Mourabit, A.; Zancanella, M.A.; Tilvi, S.; Romo, D.

    O O proline ornithine arginine histidine lysine simple precursors c o mp le x mo no m e r s , d i mer s a n d t e t r a m e rs reactive intermediates H N O stylissadine A O NH Br Br NH O HN Br Br N O HN NH 2 N HN H 2 N OH N H O NH Br Br NH O HN... biosynthetic studies, still leaves the question unanswered. Based on some synthetic studies and the isolation of a C 11 N 5 diketopiperazine, verpacamide C (18), Al-Mourabit and coworkers proposed proline or arginine as early precursors for both the pyrrole...

  16. Diethyl 2-amino-5-[(E-(1-methyl-1H-pyrrol-2-ylmethylideneamino]thiophene-3,4-dicarboxylate

    Stéphane Dufresne

    2010-12-01

    Full Text Available The structure of the title compound, C16H19N3O4S, shows the planes described by the thiophene and the pyrroles are twisted by 17.06 (4°. Additionally, the structure shows the azomethine bond adopts the E configuration, while the pyrrole is disordered as a heterocycle flip [occupancy ratio 0.729 (5:0.271 (5]. The three-dimensional network is well packed and involves N–H...O hydrogen bonding and π–π stacking [centroid–centroid distance = 4.294 (8 Å].

  17. Synthesis of furans and pyrroles via migratory and double migratory cycloisomerization reactions of homopropargylic aldehydes and imines

    Shiroodi, Roohollah Kazem; Vera, Claudia I. Rivera; Dudnik, Alexander S.; Gevorgyan, Vladimir

    2015-01-01

    A novel gold-catalyzed divergent sysnthesis of furans and pyrroles employing readily available homopropargylic aldehydes and imines have been developed. The regiochemical outcome of this reaction is dependent on the substituent on the terminal alkyne of substrate. Thus, substrates possessing alkyl and aryl substituent at the alkyne moiety produce 2,3,5-substituted furans and pyrroles via a migratory cycloisomerizaton reaction. Whereas, their silicon analogues are capable to undergo a double migratory process leading to 2,3,4-substituted heterocycles. PMID:26185336

  18. Ethyl (2E-2-cyano-3-(1-methyl-1H-pyrrol-2-ylprop-2-enoate

    Abdullah M. Asiri

    2011-09-01

    Full Text Available The 15 non-H atoms of the title compound, C11H12N2O2, are approximately coplanar, the r.m.s. deviation being 0.145 Å. The major deviation from coplanarity is seen in a twist between the ethene (E configuration and pyrrole rings [C—C—N—C torsion angle = −8.26 (18°]. The carbonyl O and cyano N atoms are syn to each other. In the crystal, supramolecular linear tapes linked by C—H...O and C—H...N interactions are further connected by C—H...π(pyrrole interactions.

  19. Polymers and copolymers of pyrrole and thiophene as electrodes in lithium cells

    Pinto, M.I.S. de; Mishima, H.T.; Mishima, B.A.L. de [Universidad Nacional de Santiago del Estero (Argentina). Inst. de Cs. Quimicas

    1997-07-01

    The performance of pyrrole and thiophene polymer electrodes in lithium cells has been examined in the lithium perchlorate-propylene carbonate electrolyte by cyclic voltammetry. Polypyrrole films were synthesized in `wet` and `dry` conditions; pyrrole and thiophene copolymers were prepared at different potentials and bilayers were prepared by sequential deposition of polythiophene (PTh) and polypyrrole (PPy) films. The polymers were cycled between 2.0V and 4.0V in the lithium cells. The effects of disconnecting the electrodes from the cell on the behaviour of the polymers regarding doping and coulombic efficiency were also studied. The cycling performance of the `wet` PPy is better than `dry` PPy, bilayer PTg/PPy and copolymers. No mixed behaviour was observed for a bilayer where the inner layer was polythiophene and the outer layer was polypyrrole with a thickness PP6/Pth ratio equal to ten. The copolymer prepared at 3.9V vs Li/Li{sup +} showed the higher energy capacity in Wh kg{sup -1} calculated from the anodic charge. (Author)

  20. Molecular distributions and geochemical implications of pyrrolic nitrogen compounds in the Permian Phosphoria Formation derived oils of Wyoming

    Silliman, J.E.; Li, M.; Yao, H. [Geological Survey of Canada, Calgary, Alberta (Canada); Hwang, R. [Chevron Petroluem Technology Company, Richmond, CA (United States)

    2002-05-01

    Crude oils from the Laramide structures of Wyoming were studied with respect to their geochemical compositions. The sampling areas include the Greater Green River, Wind River and Big Horn basins, and the Casper Arch region. Based on pristane/phytane ratio and various hopane and sterane parameters, the Permian Phosphoria Formation derived oils can be readily differentiated from oils with different origins. Within the Phosphoria Formation derived oils, three subgroups can be identified using T{sub s}/(T{sub s} + T{sub m}) and diasterane/regular sterane ratios, corresponding to sources with subtle variation in organic facies and/or thermal maturity of the Phosphoria Formation. Differences in source organic input, depositional environments, and thermal maturity were observed to greatly influence the saturated hydrocarbon compositions of the Permian Phosphoria Formation derived oils. However, the distributions of pyrrolic nitrogen compounds in these oils do not appear as diagnostic as the conventional hydrocarbon parameters commonly used as indicators of these geological factors. This fact may be related to the more significant role of oil migration in the modification of pyrrolic nitrogen compound distributions in foreland basins as compared to that in rift basins. The recognition of possible source and maturity effects on pyrrolic nitrogen compounds suggests that all of these factors should be taken into proper consideration before the pyrrolic nitrogen compounds are used as indicators for any specific geological process. (Author)

  1. One electron vs. two electron electrochemical and chemical oxidation of electron-donor substituted diketo-pyrrolo-pyrroles

    Luňák jr., S.; Eliáš, Z.; Mikysek, T.; Vyňuchal, J.; Ludvík, Jiří

    2013-01-01

    Roč. 106, SEP 2013 (2013), s. 351-359. ISSN 0013-4686 Grant ostatní: GA ČR(CZ) CZ.1.07/2.3.00/30.0021 Institutional support: RVO:61388955 Keywords : Diketo-pyrrolo-pyrroles * electrochemistry * Absorption spectra Subject RIV: CG - Electrochemistry Impact factor: 4.086, year: 2013

  2. Electrochemical Detection of Clenbuterol in Pig Liver at Pyrrole-DNA Modified Boron-doped Diamond Electrode

    WU Jing; LI Xiao-li; WU Xu-mei; HUAN Shuang-yan; SHEN Guo-li; YU Ru-qin

    2005-01-01

    The direct detection of clenbuterol(CL) in pig liver without any extraction separation at a pyrrole-DNA modified boron-doped diamond(BDD) electrode is reported. The pyrrole-DNA modified BDD electrode has a strong electrocatalytic effect on the redox reaction of CL. One oxidization and two reduction peaks of CL appear at 340.2, 299.8 and 166.6 mV(versus SCE), respectively. The pyrrole polymer alone cannot electrocatalyze the above reaction at a BDD electrode; the electrocatalytic effect of a BDD electrode modified with DNA membrane is unsufficient for the analytical detection of CL; the replacement of boron-doped diamond by glass carbon makes the electrocatalytic reaction impossible; the redox process is pH dependent. The influences of various experimental parameters on the pyrrole-DNA modified BDD electrode were investigated. A sensitive cyclic voltammetric response for CL was obtained in a linear range from 3.4×10-6 to 5×10-4 mol/L with a detection limit of 8.5×10-7 mol/L. A mean recovery of 102.7% of CL in the pig liver sample solution and a reproducibility of 3.2% were obtained.

  3. Theoretical and Experimental Study of Proton Transfer Reaction Dynamics in Pyrrole 2-Caboxyldehyde

    Chowdhury, Papia; Pathak, Anirban

    2009-01-01

    Photophysical and photochemical dynamics of ground state and excited state proton transfer reaction is reported for Pyrrole 2-Caboxyldehyde (PCL). Steady state absorption and emission measurements are conducted in this five member heterocyclic system (PCL). The theoretical investigation is done by using different quantum mechanical methods (e.g. Hartree Fock, DFT, MP2, CCSD etc.). The reaction pathway and two dimensional potential energy surfaces are computed in various level of theory. A transition state is also reported in gas phase and reaction filed calculation. It is established that PCL forms different emitting species in different media. A large Stokes shifted emission band, which is attributed to species undergoing excited state intramolecular proton transfer, is observed in hydrocarbon solvent. Intermolecular proton transfer is observed in hydroxylic polar solvent. Experimental observations yield all possible signatures of intramolecular and intermolecular proton transfer in excited state of PCL. The...

  4. Outer-Sphere Mechanism in the Oxidation of Pyrrole-2- Carboxaldehyde by Hexacyanoferrate (III Complex.

    Abd-Alhakeem H. Abu-Nawwas

    2014-01-01

    Full Text Available The kinetics and mechanism of base-catalyzed oxidation of pyrrole-2-carboxaldehyde with hexacyanoferrate (III is reported. The reaction showed first order with respect to aldahyde , alkali and hexaeyanoferrate(III. The kinetic data suggest that the oxidation involves the formation of an anion of the substrate undergoes oxidation with hexaeyanoferrate(III via outer sphere mechanism process. The free radical thus produced is further oxidized to form the final products. A suitable mechanism was proposed and rate law was derived as − d[Fe CN 6 ] 3− = 2k1k2 RC(OH2 [Fe CN 6 ] 3−[OH−] k−1 H2O

  5. Crystal structure of 1-benzyl-4-formyl-1H-pyrrole-3-carb-oxamide.

    Zhong, Qi-Di; Hu, Sheng-Quan; Yan, Hong

    2016-02-01

    In the title compound, C13H12N2O2 (I), the mean planes of the pyrrole and benzyl rings are approximately perpendicular, forming a dihedral angle of 87.07 (4) °. There is an intra-molecular N-H⋯O hydrogen bond forming an S(7) ring motif. In the crystal, mol-ecules are linked via a pair of N-H⋯O hydrogen bonds forming inversion dimers. C-H⋯O hydrogen bonds link the dimers into chains along direction [10-1]. The chains are further linked by weak C-H⋯π inter-actions forming layers parallel to the ac plane. PMID:26958371

  6. Tumor Repression of VCaP Xenografts by a Pyrrole-Imidazole Polyamide.

    Amanda E Hargrove

    Full Text Available Pyrrole-imidazole (Py-Im polyamides are high affinity DNA-binding small molecules that can inhibit protein-DNA interactions. In VCaP cells, a human prostate cancer cell line overexpressing both AR and the TMPRSS2-ERG gene fusion, an androgen response element (ARE-targeted Py-Im polyamide significantly downregulates AR driven gene expression. Polyamide exposure to VCaP cells reduced proliferation without causing DNA damage. Py-Im polyamide treatment also reduced tumor growth in a VCaP mouse xenograft model. In addition to the effects on AR regulated transcription, RNA-seq analysis revealed inhibition of topoisomerase-DNA binding as a potential mechanism that contributes to the antitumor effects of polyamides in cell culture and in xenografts. These studies support the therapeutic potential of Py-Im polyamides to target multiple aspects of transcriptional regulation in prostate cancers without genotoxic stress.

  7. Depopulation of Single-Phthalocyanine Molecular Orbitals upon Pyrrolic-Hydrogen Abstraction on Graphene.

    Néel, Nicolas; Lattelais, Marie; Bocquet, Marie-Laure; Kröger, Jörg

    2016-02-23

    Single-molecule chemistry with a scanning tunneling microscope has preponderantly been performed on metal surfaces. The molecule-metal hybridization, however, is often detrimental to genuine molecular properties and obscures their changes upon chemical reactions. We used graphene on Ir(111) to reduce the coupling between Ir(111) and adsorbed phthalocyanine molecules. By local electron injection from the tip of a scanning tunneling microscope the two pyrrolic H atoms were removed from single phthalocyanines. The detachment of the H atom pair induced a strong modification of the molecular electronic structure, albeit with no change in the adsorption geometry. Spectra and maps of the differential conductance combined with density functional calculations unveiled the entire depopulation of the highest occupied molecular orbital upon H abstraction. Occupied π states of intact molecules are proposed to be emptied via intramolecular electron transfer to dangling σ states of H-free N atoms. PMID:26812093

  8. Synthesis of conducting copolymers of thiophene capped poly(ethylene oxide) with pyrrole and thiophene

    Thiophene capped poly(ethylene oxide) (PEO) was synthesized. Copolymerisations of PEO with pyrrole (Py) and thiophene (Th) were achieved in water-sodium dodecyl sulfate (SDS) and acetonitrile (AN)-tetrabutylammonium tetrafluoroborate (TBAFB) solvent electrolyte couples via constant potential electrolyses. Characterisations of the samples were performed by NMR, cyclic voltammetry (CV), FT-IR, scanning electron microscopy (SEM). Electrical conductivities were measured by the four-probe technique. PEO-co-PTh film which was synthesized on ITO-glass in boron fluoride-ethyl ether (BFEE) found to exhibit electrochromic behaviour and it electrochemically switches between blue oxidized and red reduced states. Optical analyses were carried out to investigate the electronic structure of PEO-co-PTh electrochromic copolymer

  9. Emission and absorption of light in poly pyrrole synthesized by plasma

    The poly pyrrole structure (PPy) consists of heterocyclic rings with conjugation that it depends on the intensity of the electric field applied during the synthesis, and its luminescence is related with the π-π* transitions of that conjugation. To irradiate with light of different wavelengths, the results indicate that the polymer absorbs in the interval from 290 to 700 nm and it emits between 450 and 470 nm. The basal conductivity of the polymers, without electromagnetic excitation, it was measured in 10-15 S/cm, however, to interact with visible light it is increased approximately 10 times and when excite with UV light it is increased up to 3 magnitude orders. (Author)

  10. Supramolecular biosensors based on electropolymerised pyrrole-cyclodextrin modified surfaces for antibody detection.

    Wajs, Ewelina; Fernández, Núria; Fragoso, Alex

    2016-06-01

    The self-assembly of an adamantane-appended polymer bearing an antigen fragment on a polypyrrole-cyclodextrin modified surface provides a highly sensitive immunosensor with low limits of detection for celiac disease related targets. The pyrrole-carboxylic acid films were formed on the surface of gold electrodes by electropolymerisation and followed by covalent attachment of cyclodextrin units. Surface plasmon resonance measurements confirmed the role of the host/guest interactions between adamantane moieties and β-cyclodextrin hosts in the formation of the supramolecular sensor interface. Furthermore, this novel electrochemical supramolecular platform was effective in the amperometric detection of anti-gliadin antibodies in spiked serum samples with very good signal recovery. PMID:27097527

  11. ELECTRICALLY CONDUCTIVE COMPOSITE PREPARED BY ELECTROCHEMICAL POLYMERIZATION OF PYRROLE IN POLY- (p- PHENYLENE TEREPHTHALAMIDE ) MATRIX

    BI Xiantong; PEI Qibing; HAN Baozhen; BAO Jingshen

    1991-01-01

    The preparation of PPy/PPTA conductive composite films by electrochemical method is presented.The first step is to cast a thin layer of poly (p-phenylene-terephthalamide)(PPTA)on a slice of Pt working electrode. The second step is to electrochemically polymerize pyrrole on the PPTA/Pt working electrode. Both of the electrical conductivity and the mechanical properties of the PPy/PPTA composite film are better than those of the pure PPy film, and the film has excellent flexibility at low temperature, even in liquid nitrogen.The SEM picture of the cross-section of PPy/PPTA composite film showed that the two components were well mixed.Cyclic voltammograms of PPy/PPTA film in aqueous solution showed that the conductive films could be reduced and reoxidized.

  12. Gamma irradiation effect on polymers derived of pyrrole synthesized by plasma

    This work studies the effect of gamma irradiation at doses of 50, 100, 200, 400 and 800 kGy on polymers obtained from pyrrole synthesized by plasma. The evolution of the structure was studied by Fourier transform infrared spectroscopy (Ftir) and X-ray photoelectron spectroscopy (XPS). The Ftir spectra show that poly pyrroles have N-H, C-H, C=O, triple and consecutive double bonds in their structure. The irradiated polymers show the same chemical groups in their structure without significant changes. Nevertheless, a more detailed analysis by XPS allows the identification of superficial chemical states, such as: C=CH-C, C=CC-C, C-NH-C, C-NC-C, etc., and shows that most of these states are present in all polymers but with different participation. One possible mechanism indicates that as the irradiation dose increases, dehydrogenation processes are performed increasing fragmentation, crosslinking and formation of multiple bonds. The fragmentation and thermal degradation were studied by thermogravimetric analysis, indicating that the loss of moisture and light compounds formed during gamma irradiation occurs in the firsts 100 grades C. The main degradation of all polymers occurs from 150 to 700 grades C, suggesting that the thermal stability is independent of the irradiation dose in the interval studied. Morphology was studied using scanning electron microscopy techniques. Before irradiation, the polymer presented a uniform and practically smooth surface, however, after gamma irradiation, the applied energy increased roughness and macro fragmentation. The roughness and functional groups on the surface reduced the contact angle with water as the irradiation dose increased. However, the polymers are hydrophilic, because for all doses that contact angle is smaller than 90 grades C. Electrical conductivity was calculated respect to temperature in the interval from 25 to 100 grades C. Conductivity increases with temperature and is slightly greater in the irradiated polymers

  13. Optoelectrochemical properties of the copolymer of 2,5-di(4-methylthiophen-2-yl)-1-(4-nitrophenyl)-1H-pyrrole monomer with 3,4-ethylenedioxythiophene

    Ak, Metin [Department of Chemistry, Middle East Technical University, 06531, Ankara (Turkey); Department of Chemistry, Faculty of Art and Sciences, Pamukkale University, 20017 Denizli (Turkey)], E-mail: metinak@pau.edu.tr; Tanyeli, Cihangir [Department of Chemistry, Middle East Technical University, 06531, Ankara (Turkey)], E-mail: tanyeli@metu.edu.tr; Akhmedov, Idris M. [Department of Chemistry, Middle East Technical University, 06531, Ankara (Turkey)], E-mail: idrism@chem.metu.edu.tr; Toppare, Levent [Department of Chemistry, Middle East Technical University, 06531, Ankara (Turkey)], E-mail: toppare@metu.edu.tr

    2008-04-30

    Copolymer of 2,5-di(4-methylthiophen-2-yl)-1-(4-nitrophenyl)-1H-pyrrole (MTNP) with 3,4-ethylene dioxythiophene (EDOT) was electrochemically synthesized and characterized via cyclic voltammetry, Fourier Transform Infrared spectroscopy, Scanning Electron Microscopy, conductivity measurements. Spectroelectrochemical investigations showed that resulting copolymer film has distinct electrochromic properties. It has five different colors (dark purple, red, light grey, green, blue). At the neutral state {lambda}{sub max} due to the {pi}-{pi}* transition was found to be 500 nm and E{sub g} was calculated as 1.71 eV. Double potential step chronoamperometry experiment shows that copolymer film has good stability, fast switching time (1.1 s) and high optical contrast (30%). Electrochromic device based on P(MTNP-co-EDOT) and PEDOT was constructed and characterized. Oxidized state of the device shows dark purple color with a blue color reduced state. At interval potentials device has good transparency and colors of the device are yellow and grey. Maximum contrast and switching time of the device were measured as 23% and 1.1 s at 650 nm.

  14. Optoelectrochemical properties of the copolymer of 2,5-di(4-methylthiophen-2-yl)-1-(4-nitrophenyl)-1H-pyrrole monomer with 3,4-ethylenedioxythiophene

    Copolymer of 2,5-di(4-methylthiophen-2-yl)-1-(4-nitrophenyl)-1H-pyrrole (MTNP) with 3,4-ethylene dioxythiophene (EDOT) was electrochemically synthesized and characterized via cyclic voltammetry, Fourier Transform Infrared spectroscopy, Scanning Electron Microscopy, conductivity measurements. Spectroelectrochemical investigations showed that resulting copolymer film has distinct electrochromic properties. It has five different colors (dark purple, red, light grey, green, blue). At the neutral state λmax due to the π-π* transition was found to be 500 nm and Eg was calculated as 1.71 eV. Double potential step chronoamperometry experiment shows that copolymer film has good stability, fast switching time (1.1 s) and high optical contrast (30%). Electrochromic device based on P(MTNP-co-EDOT) and PEDOT was constructed and characterized. Oxidized state of the device shows dark purple color with a blue color reduced state. At interval potentials device has good transparency and colors of the device are yellow and grey. Maximum contrast and switching time of the device were measured as 23% and 1.1 s at 650 nm

  15. Catalytic formal [2+2+1] synthesis of pyrroles from alkynes and diazenes via TiII/TiIV redox catalysis

    Gilbert, Zachary W.; Hue, Ryan J.; Tonks, Ian A.

    2016-01-01

    Pyrroles are structurally important heterocycles. However, the synthesis of polysubstituted pyrroles is often challenging. Here, we report a multicomponent, Ti-catalysed formal [2+2+1] reaction of alkynes and diazenes for the oxidative synthesis of penta- and trisubstituted pyrroles: a nitrenoid analogue to classical Pauson-Khand-type syntheses of cyclopentenones. Given the scarcity of early transition-metal redox catalysis, preliminary mechanistic studies are presented. Initial stoichiometric and kinetic studies indicate that the mechanism of this reaction proceeds through a formally TiII/TiIV redox catalytic cycle, in which an azatitanacyclobutene intermediate, resulting from [2+2] alkyne + Ti imido coupling, undergoes a second alkyne insertion followed by reductive elimination to yield pyrrole and a TiII species. The key component for catalytic turnover is the reoxidation of the TiII species to a TiIV imido via the disproportionation of an η2-diazene-TiII complex.

  16. Zur Reaktion von Pyroglutaminsäure-Derivaten mit Phosphorpentachlorid - Darstellung chlorierter Pyrrol-2-carbonsäure-Derivate (Aminosäuren ; 9)

    Effenberger, Franz; Müller, Wolfgang; Isak, Heinz

    1987-01-01

    N-Benzyl-5-oxoprolinester 5 werden mit PCl5 über verschiedene chlorierte Zwischenstufen zu N-Benzyl-4,5-dichlor-1H-pyrrol-2-carbonsäureestern 6 chloriert, während N-Benzhydryl- L-3 und N-Acyl-5-oxoprolinester L-4 mit PCl5 unter Abspaltung des N-Substituenten L-4,4,5-Trichlor-3,4-dihydro-2H-pyrrol-2-carbon-säureester 18 bilden, die mit Base in die 4,5-Dichlor-1H-pyrrol-2-carbonsäureester 20 übergehen. Diese Umsetzungen stellen die beste Methode zur Herstellung von 4,5-Dichlor-1H-pyrrol-2-carbo...

  17. Ruthenium(II)-catalyzed synthesis of pyrrole- and indole-fused isocoumarins by C-H bond activation in DMF and water

    Singh, K.S.; Sawant, S.G.; Dixneuf, P.H.

    isocoumarin derivatives. These catalytic reactions can be performed in DMF and competively in water. COMMUNICATION Keisham S. Singh*,Sneha G. Sawant, Pierre H. Dixneuf * Page No. – Page No. Ruthenium(II) catalysed synthesis of pyrrole...

  18. Strikingly different luminescent properties arising from single crystals grown from solution or from the vapor phase in a diketo-pyrrolo-pyrrole analog

    Imoda, Tomohiko; Mizuguchi, Jin

    2007-01-01

    The title compound di-cyano-pyrrolo-pyrrole (DCPP) is an analog of diketo-pyrrolo-pyrrole (DPP) known as a red pigment on the market. Brilliant orange photoluminescence has been observed in crystals of DCPP recrystallized from solution (crystal I); whereas the luminescence was quite weak in single crystals grown from the vapor phase (crystal II). To elucidate the difference in luminescent properties, a series of structural analysis together with thermal analysis has been carried out on crysta...

  19. Organocatalytic asymmetric Henry reaction of 1H-pyrrole-2,3-diones with bifunctional amine-thiourea catalysts bearing multiple hydrogen-bond donors.

    Zhang, Ming-Liang; Yue, Deng-Feng; Wang, Zhen-Hua; Luo, Yuan; Xu, Xiao-Ying; Zhang, Xiao-Mei; Yuan, Wei-Cheng

    2016-01-01

    For the first time, a catalytic asymmetric Henry reaction of 1H-pyrrole-2,3-diones was achieved with a chiral bifunctional amine-thiourea as a catalyst possessing multiple hydrogen-bond donors. With this developed method, a range of 3-hydroxy-3-nitromethyl-1H-pyrrol-2(3H)-ones bearing quaternary stereocenters were obtained in acceptable yield (up to 75%) and enantioselectivity (up to 73% ee). PMID:26977188

  20. Highly enantioselective synthesis of beta-heteroaryl-substituted dihydrochalcones through Friedel-Crafts alkylation of indoles and pyrrole.

    Wang, Wentao; Liu, Xiaohua; Cao, Weidi; Wang, Jun; Lin, Lili; Feng, Xiaoming

    2010-02-01

    A highly enantioselective Friedel-Crafts (F-C) alkylation of indoles and pyrrole with chalcone derivatives catalyzed by a chiral N,N'-dioxide-Sc(OTf)(3) complex has been developed that tolerates a wide range of substrates. The reaction proceeds in moderate to excellent yields and high enantioselectivities (85-92 % enantiomeric excess) using 2 mol % (for indole) or 0.5 mol % (for pyrrole) catalyst loading, which showed the potential value of the catalyst system. Meanwhile, a strong positive nonlinear effect was observed. On the basis of the experimental results and previous reports, a possible working model is proposed to explain the origin of the activation and asymmetric induction. PMID:20013964

  1. CHANGES OF STRUCTURE AND PROPERTIES OF POLY (ETHYLENE TEREPHTHALATE)CAUSED BY IN-SITU POLYMERIZATION OF PYRROLE

    HE Jiasong; FENG Zhihai

    1991-01-01

    Conductive polymer composites based on crystalline polymer matrix have been prepared by using an in-situ polymerization process of pyrrole in amorphous poly (ethylene terephthalate) (PET) film.The DSC and WAXD measurement and SEM observation show that liquid-induced crystallization of PET matrix has occurred during the preparation of composite films. Depending upon the equilibrium degree of swelling and crystallinity, the limited depth of penetration of pyrrole molecules results in a skin-core structure of the composite film. The skin layer containing charge transfer intercalated polypyrrole has a surface resistance of 3.5 × 104 Ω. Rigid and heat-resistant polypyrrole molecules formed in PET film increase the tensile modulus and, especially, the rigidity of PET at elevated temperatures. However, they decrease the tensile strength and elongation at break, and impair the thermal ductility of PET.

  2. Green Synthesis of Ag and Pd Nanospheres, Nanowires, and Nanorods Using Vitamin B2: Catalytic Polymerisation of Aniline and Pyrrole

    Mallikarjuna N. Nadagouda

    2008-01-01

    Full Text Available For the first time, we report green chemistry approach using vitamin B2 in the synthesis of silver (Ag and palladium (Pd, nanospheres, nanowires, and nanorods at room temperature without using any harmful reducing agents, such as sodium borohydride (NaBH4 or hydroxylamine hydrochloride and any special capping or dispersing agent. Vitamin B2 was used as reducing agent as well as capping agent due to its high-water solubility, biodegradability, and low-toxicity compared with other reducing agents. The average particle size of nanoprticle was found to be Ag (average size 6.1±0.1 nm and Pd (average size 4.1±0.1 nm nanoparticles in ethylene glycol and Ag (average size 5.9±0.1 nm, and average size 6.1±0.1 nanoparticles in acetic acid and NMP, respectively. The formation of noble multiple shape nanostructures and their self assembly were dependent on the solvent employed for the preparation. When water was used as solvent media, Ag and Pd nanoparticles started to self-assemble into rod-like structures and in isopropanol Ag and Pd nanoparticles yielded wire-like structures with a thickness in the range of 10 to 20 nm and several hundred microns in length. In acetone and acetonitrile medium, the Ag and Pd nanoparticles are self-assembled into a regular pattern making nanorod structures with thicknesses ranging from 100 to 200 nm and lengths of a few microns. The so-synthesized nanostructures were characterized using scanning electron microscopy (SEM, transmission electron microscopy (TEM, energy dispersive X-ray (EDX analysis, and UV spectroscopy. The ensuing Ag and Pd nanoparticles catalyzed the reactions of aniline and pyrrole to generate polyaniline and polypyrrole nanofibers and may find various technological and biological applications. This single-step greener approach is general and can be extended to other noble metals and transition metal oxides.

  3. Copper-Catalyzed Coupling of 2-Siloxy-1-alkenes and Diazocarbonyl Compounds: Approach to Multisubstituted Furans, Pyrroles, and Thiophenes.

    Tan, Wei Wen; Yoshikai, Naohiko

    2016-07-01

    We report herein copper(II)-catalyzed cyclization reactions of silyl enol ethers derived from methyl ketones with α-diazo-β-ketoesters or α-diazoketones to afford 2-siloxy-2,3-dihydrofuran derivatives or 2,3,5-trisubstituted furans, respectively, under mild conditions. The former cyclization products serve as versatile 1,4-diketone surrogates, allowing facile preparation of 2,3,5-trisubstituted furans, pyrroles, and thiophenes. PMID:27259097

  4. Direct detection of pyridine formation by the reaction of CH (CD) with pyrrole: a ring expansion reaction

    Soorkia, Satchin; Taatjes, Craig A.; Osborn, David L.; Selby, Talitha M.; Trevitt, Adam J.; Wilson, Kevin R.; Leone, Stephen R.

    2010-03-16

    The reaction of the ground state methylidyne radical CH (X2Pi) with pyrrole (C4H5N) has been studied in a slow flow tube reactor using Multiplexed Photoionization Mass Spectrometry coupled to quasi-continuous tunable VUV synchrotron radiation at room temperature (295 K) and 90 oC (363 K), at 4 Torr (533 Pa). Laser photolysis of bromoform (CHBr3) at 248 nm (KrF excimer laser) is used to produce CH radicals that are free to react with pyrrole molecules in the gaseous mixture. A signal at m/z = 79 (C5H5N) is identified as the product of the reaction and resolved from 79Br atoms, and the result is consistent with CH addition to pyrrole followed by Helimination. The Photoionization Efficiency curve unambiguously identifies m/z = 79 as pyridine. With deuterated methylidyne radicals (CD), the product mass peak is shifted by +1 mass unit, consistent with the formation of C5H4DN and identified as deuterated pyridine (dpyridine). Within detection limits, there is no evidence that the addition intermediate complex undergoes hydrogen scrambling. The results are consistent with a reaction mechanism that proceeds via the direct CH (CD) cycloaddition or insertion into the five-member pyrrole ring, giving rise to ring expansion, followed by H atom elimination from the nitrogen atom in the intermediate to form the resonance stabilized pyridine (d-pyridine) molecule. Implications to interstellar chemistry and planetary atmospheres, in particular Titan, as well as in gas-phase combustion processes, are discussed.

  5. N-Heterocyclic carbene–palladium catalysts for the direct arylation of pyrrole derivatives with aryl chlorides

    Ismail Özdemir

    2013-02-01

    Full Text Available New Pd–NHC complexes have been synthesized and employed for palladium-catalyzed direct arylation of pyrrole derivatives by using electron-deficient aryl chlorides as coupling partners. The desired coupling products were obtained in moderate to good yields by using 1 mol % of these air-stable palladium complexes. This is an advantage compared to the procedures employing air-sensitive phosphines, which have been previously shown to promote the coupling of aryl chlorides with heteroarenes.

  6. Investigations of poly(pyrrole)-coated cotton fabrics prepared in blends of anionic and cationic surfactants as flexible electrode

    Highlights: • Poly(pyrrole)-coated cotton fabrics were prepared in mixed surfactants. • The fabrics are soft, lightweight, mechanically robust, and highly electrical conductive. • Potential applications of the fabrics as flexible electrodes were tested. • The fabric electrodes exhibited high discharge capacity and excellent cycling performance. -- Abstract: In recent years, much effort has been dedicated to achieve lightweight, stretchable and flexible energy-storage devices for wearable electronics. Here we report an everyday cotton fabric coated with poly(pyrrole) as flexible electrodes. Poly(pyrrole) nanoparticles are synthesized on the fabrics via a simple chemical polymerization process with the mixed surfactants of cetyltrimethylammonium bromide (CTAB) and sodium dodecyl benzene sulfonate (SDBS) as soft template. A highly conductive fabric with surface resistance of 14 Ω/□ can be produced by changing surfactant concentration. Such a conductive textile shows outstanding flexibility and stretchability, and demonstrates strong adhesion between the PPy and the cellulose fiber. The fabric electrode exhibits a discharge capacity of 51.7 mAh g−1 with high cycling stability (negligible decay after 100 cycles)

  7. Pyrrole PMOs, incorporating new N-heterocyclic compounds on an ethene-PMO through Diels–Alder reactions

    The ethenylene bridges on the walls of an ethenylene-bridged periodic mesoporous organosilica were successfully modified with a variety of pyrrole derivatives – pyrrole, methylpyrrole, dimethylpyrrole, trimethylpyrrole and 1-phenylpyrrole – through Diels–Alder reactions. X-ray diffraction measurements and N2 adsorption–desorption analysis confirmed the preservation of the ordering and mesoporosity of the parent material as well as the decoration of the pores with the surface Diels–Alder adducts. Moreover, other techniques such as DRIFT, 13C and 29Si nuclear magnetic resonances revealed the formation of the surface N-heterocyclic compounds at the parent ethenylene sites. - Highlights: • Chemical modification of the double bonds on an ethene-PMO through the Diels–Alder reaction. • A family of pyrrole derivatives act as dienes in the Diels–Alder reaction. • Well-ordering and mesoporosity are retained after the post-functionalization. • N-containing compounds on the surface of ethene-PMO are present after the Diels–Alder reaction

  8. Pyrrole PMOs, incorporating new N-heterocyclic compounds on an ethene-PMO through Diels–Alder reactions

    Esquivel, Dolores; De Canck, Els [Center for Ordered Materials, Organometallics and Catalysis, Department of Inorganic and Physical Chemistry, Ghent University, Krijgslaan 281-S3, 9000 Ghent (Belgium); Jiménez-Sanchidrián, César [Department of Organic Chemistry, Nanochemistry and Fine Chemistry Research Institute (IUIQFN), Faculty of Sciences, University of Córdoba, Campus de Rabanales, Marie Curie Building, Ctra. Nnal. IV, km 396, 14071 Córdoba (Spain); Romero-Salguero, Francisco J., E-mail: qo2rosaf@uco.es [Department of Organic Chemistry, Nanochemistry and Fine Chemistry Research Institute (IUIQFN), Faculty of Sciences, University of Córdoba, Campus de Rabanales, Marie Curie Building, Ctra. Nnal. IV, km 396, 14071 Córdoba (Spain); Van Der Voort, Pascal, E-mail: pascal.vandervoort@ugent.be [Center for Ordered Materials, Organometallics and Catalysis, Department of Inorganic and Physical Chemistry, Ghent University, Krijgslaan 281-S3, 9000 Ghent (Belgium)

    2014-11-14

    The ethenylene bridges on the walls of an ethenylene-bridged periodic mesoporous organosilica were successfully modified with a variety of pyrrole derivatives – pyrrole, methylpyrrole, dimethylpyrrole, trimethylpyrrole and 1-phenylpyrrole – through Diels–Alder reactions. X-ray diffraction measurements and N{sub 2} adsorption–desorption analysis confirmed the preservation of the ordering and mesoporosity of the parent material as well as the decoration of the pores with the surface Diels–Alder adducts. Moreover, other techniques such as DRIFT, {sup 13}C and {sup 29}Si nuclear magnetic resonances revealed the formation of the surface N-heterocyclic compounds at the parent ethenylene sites. - Highlights: • Chemical modification of the double bonds on an ethene-PMO through the Diels–Alder reaction. • A family of pyrrole derivatives act as dienes in the Diels–Alder reaction. • Well-ordering and mesoporosity are retained after the post-functionalization. • N-containing compounds on the surface of ethene-PMO are present after the Diels–Alder reaction.

  9. Theoretical and experimental studies on the electronic, optical, and structural properties of poly-pyrrole-2-carboxylic acid films

    Highlights: • Novel approach for preparing a functionalized polypyrrole film. • Comparative experimental and theoretical results – conjugated polymers. • Accurate electronic, structural, and optical properties obtained for poly-pyrrole-2-carboxylic acid films. • Proposal of mechanism of electropolymerization of pyrrole-2-carboxylic acid films. - Abstract: A theoretical approach is used here to explain experimental results obtained from the electrosynthesis of polypyrrole-2-carboxylic acid (PPY-2-COOH) films in nonaqueous medium. An analysis of the Fukui function (reactivity index) indicates that the monomer (pyrrole-2-carboxylic acid, PY-2-COOH), and dimers and trimers are oxidized in the C4 or C5 positions of the heterocyclic ring of the PY-2-COOH structure. After calculating the heat of formation using semiempirical Austin Model 1 post-Hartree–Fock parameterization for dimer species, both C4 and C5 positions adjacent to the aromatic rings of PPY-2-COOH were considered the most susceptible ones to oxidative coupling reactions. The ZINDO-S/CI semiempirical method was used to simulate the electronic transitions typically seen in the UV–VIS–NIR range in monomer and oligomers with different conjugation lengths. The use of an electrochemical quartz crystal microbalance provides sufficient information to propose a polymerization mechanism of PY-2-COOH based on molecular modeling and experimental results

  10. Synthesis, molecular structure and spectral analysis of ethyl 4-formyl-3,5-dimethyl-1H-pyrrole-2-carboxylate thiosemicarbazone: A combined DFT and AIM approach

    Singh, R. N.; Kumar, Amit; Tiwari, R. K.; Rawat, Poonam; Verma, Divya; Baboo, Vikas

    2012-05-01

    A new ethyl 4-formyl-3,5-dimethyl-1H-pyrrole-2-carboxylate thiosemicarbazone (EFDMPCT) has been synthesized and characterized by elemental analysis and FT-IR, 1H NMR, UV-Visible, DART-mass spectroscopy. Quantum chemical calculations have been performed by DFT level of theory using B3LYP functional and 6-31G (d,p) as basis set. The calculated 1H NMR chemical shifts using gauge including atomic orbitals (GIAO) approach are in good agreement with the observed chemical shifts. The electronic transitions within molecule have been interpreted using the time dependent density functional theory (TD-DFT). The calculated and experimental wavenumbers analyses confirm the existence of dimer. Topological parameters electron density, Laplacian of electron density, kinetic electron energy density, potential electron density and the total electron energy density at the bond critical points (BCP) analyzed using 'Atoms in Molecules' AIM theory reveals intra and inter molecular hydrogen bonding other weaker interactions in detail. The calculated intermolecular hydrogen bond energy of dimer is -12.2176 kcal/mol using AIM calculation. The results of AIM ellipticity confirm the existence of resonance assisted hydrogen bonds in dimer. The calculated thermodynamic parameters show that reaction is exothermic and non-spontaneous at room temperature. The local reactivity descriptors find the reactive sites within molecules have been calculated.

  11. Electrochromic properties of poly (1-(phenyl)-2,5-di(2-thienyl)-1H-pyrrole-co-3,4-ethylenedioxy thiophene) and its application in electrochromic devices

    Tarkuc, S.; Sahmetlioglu, E.; Tanyeli, C.; Akhmedov, I. M.; Toppare, L.

    2008-06-01

    Electrochemical copolymerization of 1-(phenyl)-2,5-di(2-thienyl)-1H-pyrrole (PTP) with 3,4-ethylenedioxy thiophene (EDOT) was carried out in acetonitrile (AN)/NaClO4/LiClO4 (0.1 M) solvent-electrolyte couple via potentiodynamic electrolysis. Characterizations of the resulting copolymer were performed via cyclic voltammetry (CV), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and spectroelectrochemical analysis. Spectroelectrochemical analyses show that the copolymer of PTP with EDOT has an electronic band gap (due to π to π∗ transition) of 1.9 eV at 480 nm, with a claret red in the fully reduced form and a blue color in the fully oxidized form. Via kinetic studies, the optical contrast (ΔT %) was found to be 8% for P(PTP-co-EDOT). Results showed that the time required to reach 95% of the ultimate transmittance was 1.7 s for the copolymer. The P(PTP-co-EDOT) film was used to construct a dual type polymer electrochromic device (ECDs) with poly(3,4-ethylenedioxy thiophene) (PEDOT). Spectroelectrochemistry, electrochromic switching and open circuit memory of the device were investigated.

  12. Vibrational spectra and electronic structure of 3-((1H-pyrrol-1-yl) methyl) naphthalen-2-ol - A computational insight on antioxidant active Mannich base

    Boobalan, Maria susai; Tamilvendan, D.; Amaladasan, M.; Ramalingam, S.; Venkatesa Prabhu, G.; Bououdina, M.

    2015-02-01

    The 3-((1H-pyrrol-1-yl) methyl) naphthalen-2-ol (IFTN) is a class of synthesized organic Mannich base compound having antioxidant property of biological importance. A meticulous normal mode vibrational analysis has been carried out by comparing and contrasting the experimentally recorded FT-IR and FT-Raman spectra with simulated spectra of IFTN. Similarly the calculated 1H and 13C NMR of IFTN were correlated with experimental findings to understand the shielding and deshielding nature hold in it. The following other electronic structure properties were calculated such as equilibrium geometrical parameters, natural bond orbital analysis (NBO), frontier molecular orbital (FMO) characterization, statistical thermochemical properties against a range of temperatures and molecular electrostatic potential (MEP) imprint was carried out along with various charges such as APT, ESP, Hirshfeld, natural and Mulliken. All these predicted properties unlock the nature of total behavior of IFTN in various dimensions. These could be Lewis, non-Lewis interaction along with their respective energies, contribution of fragmented moieties for various orders of HOMO and LUMO, temperature consequences on enthalpy, entropy, and heat capacity. In addition, the MEP leads to find electrophilic, nucleophilic reactive sites on IFTN molecular surface. The entire computational calculations has been made on HF/6-31+G/6-311++G(d,p) and B3LYP/6-31+G/6-311++G(d,p) model chemistries. A complete electronic structure observation has been achieved by this theoretical analysis.

  13. Palladium complexes of pyrrole-2-aldehyde thiosemicarbazone: Synthesis, structure and spectral properties

    Piyali Paul; Samaresh Bhattacharya

    2014-09-01

    Reaction of pyrrole-2-aldehyde thiosemicarbazone (abbreviated as H2L, where H2 stands for the two potentially dissociable protons) with [Pd(PPh3)2Cl2] in ethanol in the presence of NEt3 afforded two complexes, [Pd(PPh3)(HLNS)Cl] and [Pd(PPh3)(LNNS)], where the thiosemicarbazone ligand is coordinated to the metal centre respectively as monoanionic N,S-donor (depicted by HLNS) and dianionic N,N,S-donor (depicted by LNNS). Similar reaction with Na2[PdCl4] afforded a bis-complex, [Pd(HLNS)2]. Crystal structures of all the three complexes have been determined.With reference to the structure of the uncoordinated thiosemicarbazone (H2L), the N,S-coordinationmode observed in [Pd(PPh3)(HLNS)Cl] and [Pd(HLNS)2] is associated with a geometrical change around the imine bond.While the N,N,S-mode of binding observed in [Pd(PPh3)(LNNS)] takes place without any such geometrical change. All three complexes display intense absorptions in the visible and ultraviolet regions, which have been analyzed by TDDFT method.

  14. A concise synthesis of (+)-batzelladine B from simple pyrrole-based starting materials

    Parr, Brendan T.; Economou, Christos; Herzon, Seth B.

    2015-09-01

    Alkaloids, secondary metabolites that contain basic nitrogen atoms, are some of the most well-known biologically active natural products in chemistry and medicine. Although efficient laboratory synthesis of alkaloids would enable the study and optimization of their biological properties, their preparation is often complicated by the basicity and nucleophilicity of nitrogen, its susceptibility to oxidation, and its ability to alter reaction outcomes in unexpected ways--for example, through stereochemical instability and neighbouring group participation. Efforts to address these issues have led to the invention of a large number of protecting groups that temper the reactivity of nitrogen; however, the use of protecting groups typically introduces additional steps and obstacles into the synthetic route. Alternatively, the use of aromatic nitrogen heterocycles as synthetic precursors can attenuate the reactivity of nitrogen and streamline synthetic strategies. Here we use such an approach to achieve a synthesis of the complex anti-HIV alkaloid (+)-batzelladine B in nine steps (longest linear sequence) from simple pyrrole-based starting materials. The route uses several key transformations that would be challenging or impossible to implement using saturated nitrogen heterocycles and highlights some of the advantages of beginning with aromatic reagents.

  15. Efficient Synthesis of Peptide and Protein Functionalized Pyrrole-Imidazole Polyamides Using Native Chemical Ligation

    Brian M. G. Janssen

    2015-06-01

    Full Text Available The advancement of DNA-based bionanotechnology requires efficient strategies to functionalize DNA nanostructures in a specific manner with other biomolecules, most importantly peptides and proteins. Common DNA-functionalization methods rely on laborious and covalent conjugation between DNA and proteins or peptides. Pyrrole-imidazole (Py–Im polyamides, based on natural minor groove DNA-binding small molecules, can bind to DNA in a sequence specific fashion. In this study, we explore the use of Py–Im polyamides for addressing proteins and peptides to DNA in a sequence specific and non-covalent manner. A generic synthetic approach based on native chemical ligation was established that allows efficient conjugation of both peptides and recombinant proteins to Py–Im polyamides. The effect of Py–Im polyamide conjugation on DNA binding was investigated by Surface Plasmon Resonance (SPR. Although the synthesis of different protein-Py–Im-polyamide conjugates was successful, attenuation of DNA affinity was observed, in particular for the protein-Py–Im-polyamide conjugates. The practical use of protein-Py–Im-polyamide conjugates for addressing DNA structures in an orthogonal but non-covalent manner, therefore, remains to be established.

  16. Experimental and computational thermochemistry of 1-phenylpyrrole and 1-(4-methylphenyl)pyrrole

    Santos, Ana Filipa L.O.M. [Centro de Investigacao em Quimica, Department of Chemistry, Faculty of Science, University of Porto, Rua do Campo Alegre, 687, P-4169-007 Porto (Portugal); Ribeiro da Silva, Manuel A.V., E-mail: risilva@fc.up.p [Centro de Investigacao em Quimica, Department of Chemistry, Faculty of Science, University of Porto, Rua do Campo Alegre, 687, P-4169-007 Porto (Portugal)

    2010-06-15

    The standard (p{sup o} = 0.1 MPa) molar enthalpies of formation, in the crystalline phase, of 1-phenylpyrrole and 1-(4-methylphenyl)pyrrole, at T = 298.15 K, were derived from the standard molar energies of combustion in oxygen, measured by static-bomb combustion calorimetry. For these compounds, the standard molar enthalpies of sublimation, at T = 298.15 K, were determined from the temperature-vapour pressure dependence, obtained by the Knudsen mass-loss effusion method. Using estimated values for the heat capacity differences between the gas and the crystal phases of the studied compounds, the standard (p{sup o} = 0.1 MPa) molar enthalpies, entropies, and Gibbs energies of sublimation, at T = 298.15 K, were derived. From the experimental values, the standard molar enthalpies of formation, in the gaseous phase, at T = 298.15 K, were calculated. Additionally, the enthalpies of formation of both compounds were estimated using the composite G3(MP2)//B3LYP approach together with adequate gas-phase working reactions. There is a very good agreement between computational and experimental results.

  17. Crystal structures of unsymmetrically mixed β-pyrrole substituted nickel(II)-meso-tetraphenylporphyrins

    BHYRAPPA PUTTAIAH; VELKANNAN VEERAPANDIAN; SARANGI UJWAL KUMAR

    2016-07-01

    Crystal structures of solvated unsymmetrically substituted meso-tetraphenylporphyrins, 2,3,12,13, 17-pentachloro-5,7,8,10,15,18,20-hepta-phenylporphyrin, H₂TPP(Ph)₃(Cl)₅, 1 and its nickel(II), NiTPP(Ph)₃(Cl)₅, 2 were determined by single crystal XRD analysis. In addition, a new unsymmetricallysubstituted porphyrin, 2,3,12,13,17-pentacyano-5,7,8,10,15,18,20-heptaphenyl-porphinato nickel(II) complex, NiTPP(Ph)₃(CN)₅, 3 complex was synthesized and its solvated structure was examined by crystallography. These porphyrins exhibited dramatic nonplanar conformation of the macrocycle as evidenced from the averagedisplacement of the β-pyrrole carbon (±ΔCβ ) from the mean plane of the porphyrin ring and the trend in nonplanarity varies in the order: 2 (1.189(5) Å) > 1 (1.036(6) Å) > 3 (0.895(6) Å). The normal-coordinate structural decomposition analysis of these structures revealed mainly saddle distortion of the macrocycle combined with small degree of ruffled or domed distortions. The Hirshfeld surface analysis of structures 1-3 revealed solvate dependent intermolecular contacts with varying degree of H. . .H (43–49%), C. . .H (17–19%), H. . .Cl (25–30%) and N. . .H (~19%) contact contributions.

  18. New 1H-pyrrole-2,5-dione derivatives as efficient organic inhibitors of carbon steel corrosion in hydrochloric acid medium: Electrochemical, XPS and DFT studies

    Highlights: • 1H-pyrrole derivatives act as good corrosion inhibitors for carbon steel in 1 M HCl. • Adsorption of the inhibitors on carbon steel surface obeys Langmuir’s isotherm. • XPS showed that the inhibitors are chemisorbed on the metal surface. • Quantum chemical parameters were correlated with experimental results. - Abstract: New 1H-pyrrole-2,5-dione derivatives, namely 1-phenyl-1H-pyrrole-2,5-dione (PPD) and 1-(4-methylphenyl)-1H-pyrrole-2,5-dione (MPPD) were synthesised and their inhibitive action against the corrosion of carbon steel in 1 M HCl solution were investigated at 308 K by weight loss, potentiodynamic polarization curves, and electrochemical impedance spectroscopy (EIS) methods. The results showed that the investigated 1H-pyrrole-2,5-dione derivatives are good corrosion inhibitors for carbon steel in 1 M HCl medium, their inhibition efficiency increased with inhibitor concentration, and MPPD is slightly more effective than PPD. Potentiostatic polarization study showed that PPD and MPPD are mixed-type inhibitors in 1 M HCl. Impedance experimental data revealed a frequency distribution of the capacitance, simulated as constant phase element. The results obtained from electrochemical and weight loss studies were in reasonable agreement. The adsorption of MPPD and PPD on steel surface obeyed Langmuir’s adsorption isotherm. Thermodynamic data and XPS analysis clearly indicated that the adsorption mechanism of 1H-pyrrole-2,5-dione derivatives on carbon steel surface in 1 M HCl solution is mainly controlled by a chemisorption process. Quantum chemical calculations using the Density Functional Theory (DFT) were performed on 1H-pyrrole-2,5-dione derivatives to determine the relationship between molecular structures and their inhibition efficiencies

  19. Nerve cells culture from lumbar spinal cord on surfaces modified by plasma pyrrole polymerization.

    Zuñiga-Aguilar, E; Olayo, R; Ramírez-Fernández, O; Morales, J; Godínez, R

    2014-01-01

    Currently, there are several techniques for modified cell culture surfaces under research to improve cell growth and adhesion. Recently, different methods have been used for surface coating, using biomolecules that enhance cell attachment and growth of nerve cells from spinal cord, such as the use of Poly-DL-Ornithine/Laminin. Plasma-polymerized pyrrole (PPy)-treated surfaces have showed improvement on surfaces biocompatibility with the cells in culture since they do not interfere with any of the biological cell functions. In the present work, we present a novel mouse nerve cell culture technique, using PPy-treated cell culture surfaces. A comparative study of cell survival using Poly-DL-Ornithine/Laminin-treated surfaces was performed. Our results of cell survival when compared with data already reported by other investigators, show that cells cultured on the PPy-modified surface increased survival up to 21 days when compared with Poly-DL-Ornithine/Laminin-coated culture, where 8 days cell survival was obtained. There were electrical and morphological differences in the nerve cells grown in the different surfaces. By comparing the peak ion currents of Poly-DL-Ornithine/Laminin-seeded cells for 8 days with cells grown for 21 days on PPy, an increase of 516% in the Na(+) current and 127% in K(+) currents in cells seeded on PPy were observed. Immunofluorescence techniques showed the presence of cell synapses and culture viability after 21 days. Our results then showed that PPy-modified surfaces are an alternative culture method that increases nerve cells survival from lumbar spinal cord cell culture by preserving its electrical and morphological features. PMID:24650203

  20. Morphological and physicochemical properties of dip-coated poly {(2,5-diyl pyrrole) [4-nitrobenzylidène]} (PPNB) thin films: towards photovoltaic applications

    Mouchaal, Younes; Gherrass, Hamou; Bendoukha Reguig, Abdelkarim; Hachemaoui, Aïcha; Yahiaoui, Ahmed; Makha, Mohamed; Khelil, Abdelbacet; Bernede, Jean-Christian

    2015-02-01

    A new material: conjugated poly {(2,5-diyl pyrrole) [4-nitrobenzylidène]}, that we called (PPNB), has been synthesized and characterized. The cyclic voltammetry has been used in order to estimate first oxidation (Ep) and reduction (En) potentials of our polymer. These values have been assigned, respectively, to the position of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) and determination of the energy band gap which have been estimated to be 6.16, 3.89 and 2.27 eV respectively. Energy levels values of the HOMO and LUMO of the PPNB polymeric donor material were evaluated and the results are compatible with an electron transfer to C60 within an eventual junction, such values show that PPNB could be probed for applications in organic solar cells as donor material. PPNB Thin films have been deposited by dip-coating technique from Dichloromethane solvent with different polymer concentrations, and a dipping speed of 3.0 cm/min. For morphological characterization of the films scanning electron microscopy (SEM) was carried out. The samples, when observed by SEM, reveals that the films deposited are less dense, uniform. Cross-sectional SEM micrographs PPNB films show that thickness of the layers is homogeneous and has value of 35-40 nm. Optical characteristics of the polymer thin films were studied using UV-vis spectroscopy; absorption of wide range of wavelengths from 350 to 700 nm was observed. The optical band gap energy ranges between 1.9 eV and 1.94 eV. Based on these analyzes we realized heterojunction organic solar cells with the structure: ITO/Au/PPNB/C60/BCP/Al, the cells had a photovoltaique effect after J-V measuring, however the efficiency of photo generation under AM1.5 illumination was weak (about 0.02%) and needs to be improved.

  1. Synthesis and electrochemical properties of novel, donor–acceptor pyrrole derivatives with 1,8-naphthalimide units and their polymers

    A new class of bipolar monomers with pyrrole or thiophene–pyrrole–thiophene as electron donor and 1,8-naphthalimide as electron acceptor unit is reported. Donor–acceptor conjugated polymers were generated electrochemically. The synthesis of monomers, optical, electrochemical and spectroelectrochemical properties supported by theoretical calculations are presented. 1,8-naphthalimide units were attached directly to pyrrole in compounds 1a and 2a or by different bridges in the case of 1b and 2b. Intra-molecular donor–acceptor interactions of the monomers and its polymers were investigated using cyclic voltammetry, in-situ UV–Vis-NIR, electron spin resonance (ESR) spectroelectrochemistry and fluorescence spectroscopy. Studied compounds present large discrepancy (up to 1.31 eV for 2a) between energy gap values determined through electrochemical and optical measurements. The Time-dependent density functional theory (TDDFT) calculations help to explain this discrepancy. This is caused by weak HOMO to LUMO transition, 2000 times weaker than HOMO−2 to LUMO or HOMO to LUMO+1 transition. Altering the structure of monomers yields different stability and properties of obtained polymers. The p- and n-doping processes are separated. Anions are localized mainly on 1,8-naphthalimide units. Cations are localized mainly on pyrrole or thiophene–pyrrole–thiophene moiety and their polymer chains. Attachment of the additional thiophene units decreases the oxidation potential of the monomer and reduces the influence of the steric hindrance between 1,8-naphthalimide moiety and polymer/oligomers chain. This new class of model compounds is promising for use as a material with enhanced charge separation for wide range of optoelectronic, electrochromic and photovoltaic applications

  2. A Hydrogen Peroxide Sensor Prepared by Electropolymerization of Pyrrole Based on Screen-Printed Carbon Paste Electrodes

    Hui Xu

    2007-03-01

    Full Text Available A disposable amperometric biosensor for commercial use to detect hydrogenperoxide has been developed. The sensor is based on screen-printed carbon paste electrodesmodified by electropolymerization of pyrrole with horseradish peroxidase (HRP entrapped.The facture techniques of fabricating the enzyme electrodes are suitable for mass productionand quality control. The biosensor shows a linear amperometric response to H2O2 from 0.1to 2.0 mM, with a sensitivity of 33.24 μA mM-1 cm-2. Different operational parameters ofelectropolymerization are evaluated and optimized.

  3. Hepatoselectivity of statins: design and synthesis of 4-sulfamoyl pyrroles as HMG-CoA reductase inhibitors.

    Park, William K C; Kennedy, Robert M; Larsen, Scott D; Miller, Steve; Roth, Bruce D; Song, Yuntao; Steinbaugh, Bruce A; Sun, Kevin; Tait, Bradley D; Kowala, Mark C; Trivedi, Bharat K; Auerbach, Bruce; Askew, Valerie; Dillon, Lisa; Hanselman, Jeffrey C; Lin, Zhiwu; Lu, Gina H; Robertson, Andrew; Sekerke, Catherine

    2008-02-01

    4-Sulfamoyl pyrroles were designed as novel hepatoselective HMG-CoA reductase inhibitors (statins) to reduce myalgia, a statin-induced adverse effect. The compounds were prepared via a [3+2] cycloaddition of a Münchnone with a sulfonamide-substituted alkyne. We identified compounds with greater selectivity for hepatocytes compared to L6-myocytes than rosuvastatin and atorvastatin. There was an inverse correlation of myocyte potencies and ClogP values. A number of analogs were effective at reducing cholesterol in acute and chronic in vivo models but they lacked sufficient chronic in vivo activity to warrant further development. PMID:18155906

  4. Ru-Catalysed C–H Arylation of Indoles and Pyrroles with Boronic Acids: Scope and Mechanistic Studies

    Sollert, Carina; Devaraj, Karthik; Orthaber, Andreas; Gates, Paul J; Pilarski, Lukasz T

    2015-01-01

    The Ru-catalysed C2–H arylation of indoles and pyrroles by using boronic acids under oxidative conditions is reported. This reaction can be applied to tryptophan derivatives and tolerates a wide range of functional groups on both coupling partners, including bromides and iodides, which can be further derivatised selectively. New indole-based ruthenacyclic complexes are described and investigated as possible intermediates in the reaction. Mechanistic studies suggest the on-cycle intermediates do not possess a para-cymene ligand and that the on-cycle metalation occurs through an electrophilic attack by the Ru centre. PMID:25689052

  5. Rhodium and iridium complexes of N-(2'-hydroxyphenyl)pyrrole-2-aldimine: Synthesis, structure, and spectral and electrochemical properties

    Semanti Basu; Indrani Pal; Ray J Butcher; Georgina Rosair; Samaresh Bhattacharya

    2005-03-01

    Reaction of N-(2'-hydroxyphenyl)pyrrole-2-aldimine (H2L) with [M(PPh3)3Cl] (M = Rh, Ir) affords complexes of type [M(PPh3)2(L)Cl]. Structures of both complexes have been determined by X-ray crystallography. In both complexes, the N-(2'-hydroxyphenyl)pyrrole-2-aldimine ligand is coordinated to the metal centre, via dissociation of the acidic protons, as a dianionic tridentate N,N,O-donor. The M(L)Cl fragment constitutes an equatorial plane with the metal at the centre and the two PPh3 ligands occupying axial positions. The complexes are diamagnetic (low-spin 6, = 0) and show intense MLCT transitions in the visible region. Cyclic voltammetry of the [M(PPh3)2(L)Cl] complexes shows reversible M(III)-M(IV) oxidation near 0.5 V vs SCE and quasi-reversible ligand-centred oxidative response near 1.0 V vs SCE.

  6. Synthesis and Crystal Structure of N-(1'-H-Pyrrol-2'-ylcarbonyl)-5-amino-1,10-phenanthroline

    WANG Yue-Hong; LIN Hai; LIN Hua-Kuan

    2008-01-01

    The title compound,N-(1'-H-pyrrol-2'-ylcarbonyl)-5-amino-1,10-phenanthroline,was synthesized by the reaction of a-pyrrolyl carbonyl chloride and 5-amino-1,10-phenanthroline in pyridine.Determined by X-ray structure analysis,it crystallizes in triclinic system,space group P(1)with the following crystallographic data:C20H21N5O3,Mr=379.42,a=7.8559(4),b=9.1681(6),c =14.6818(9)(A),α=73.254(10),β=88.938(15),γ=68.080(10)°,V=934.66(10)(A)3,Z=2,F(000)=400.Dc=1.348 g/cm3 and μ=0.094 mm-1.The final R=0.0680 and wR=0.1419 for 2142observed reflections with I>2σ(I),and R=0.1084 and wR=0.1643 for all reflections.Two aromatic ring planes(pyrrole and phenanthroline rings)are connected by the amide plane.Two title complex molecules are connected through hydrogen bonds and weak π-π stacking interactions to generate a 3-D supramolecule.

  7. Radiosynthesis and in vivo evaluation of [{sup 11}C]-labelled pyrrole-2-carboxamide derivates as novel radioligands for PET imaging of monoamine oxidase A

    De Bruyne, Sylvie [Laboratory for Radiopharmacy, Ghent University, 9000 Ghent (Belgium); La Regina, Giuseppe [Istituto Pasteur, Fondazione Cenci Bolognetti, Dipartimento di Chimica e Tecnologie del Farmaco, Sapienza Universita di Roma, I-00185 Rome (Italy); Staelens, Steven [IBITECH-Medisip, Ghent University-IBBT, 9000 Ghent (Belgium); Wyffels, Leonie [Laboratory for Radiopharmacy, Ghent University, 9000 Ghent (Belgium); Deleye, Steven [IBITECH-Medisip, Ghent University-IBBT, 9000 Ghent (Belgium); Silvestri, Romano [Istituto Pasteur, Fondazione Cenci Bolognetti, Dipartimento di Chimica e Tecnologie del Farmaco, Sapienza Universita di Roma, I-00185 Rome (Italy); De Vos, Filip [Laboratory for Radiopharmacy, Ghent University, 9000 Ghent (Belgium)], E-mail: filipx.devos@ugent.be

    2010-05-15

    Introduction: Since MAO-A is an enzyme involved in the metabolism of neurotransmitters, fluctuations in MAO-A functionality are associated with psychiatric and neurological disorders as well as with tobacco addiction and behaviour. This study reports the radiolabelling of two [{sup 11}C]-labelled pyrrole-2-carboxamide derivates, RS 2315 and RS 2360, along with the characterization of their in vivo properties. Methods: The radiolabelling of [{sup 11}C]-RS 2315 and [{sup 11}C]-RS 2360 was accomplished by alkylation of their amide precursors with [{sup 11}C]CH{sub 3}I. Biodistribution, blocking and metabolite studies of both tracers were performed in NMRI mice. Finally, a PET study in Sprague-Dawley rats was performed for [{sup 11}C]-RS 2360. Results: Both tracers were obtained in a radiochemical yield of approximately 30% with radiochemical purity of >98%. Biodistribution studies showed high brain uptake followed by rapid brain clearance for both radiotracers. In the brain, [{sup 11}C]-RS 2360 was more stable than [{sup 11}C]-RS 2315. Blocking studies in mice could not demonstrate specificity of [{sup 11}C]-RS 2315 towards MAO-A or MAO-B. The blocking and imaging study with [{sup 11}C]-RS 2360 on the other hand indicated specific binding in MAO-A at the earliest time points. Conclusions: [{sup 11}C]-RS 2315 displayed a high nonspecific binding and is therefore not suitable for visualization of MAO-A in vivo. [{sup 11}C]-RS 2360 on the other hand has potential for mapping MAO-A since specific binding is demonstrated.

  8. Radiosynthesis and in vivo evaluation of [11C]-labelled pyrrole-2-carboxamide derivates as novel radioligands for PET imaging of monoamine oxidase A

    Introduction: Since MAO-A is an enzyme involved in the metabolism of neurotransmitters, fluctuations in MAO-A functionality are associated with psychiatric and neurological disorders as well as with tobacco addiction and behaviour. This study reports the radiolabelling of two [11C]-labelled pyrrole-2-carboxamide derivates, RS 2315 and RS 2360, along with the characterization of their in vivo properties. Methods: The radiolabelling of [11C]-RS 2315 and [11C]-RS 2360 was accomplished by alkylation of their amide precursors with [11C]CH3I. Biodistribution, blocking and metabolite studies of both tracers were performed in NMRI mice. Finally, a PET study in Sprague-Dawley rats was performed for [11C]-RS 2360. Results: Both tracers were obtained in a radiochemical yield of approximately 30% with radiochemical purity of >98%. Biodistribution studies showed high brain uptake followed by rapid brain clearance for both radiotracers. In the brain, [11C]-RS 2360 was more stable than [11C]-RS 2315. Blocking studies in mice could not demonstrate specificity of [11C]-RS 2315 towards MAO-A or MAO-B. The blocking and imaging study with [11C]-RS 2360 on the other hand indicated specific binding in MAO-A at the earliest time points. Conclusions: [11C]-RS 2315 displayed a high nonspecific binding and is therefore not suitable for visualization of MAO-A in vivo. [11C]-RS 2360 on the other hand has potential for mapping MAO-A since specific binding is demonstrated.

  9. The Synthesis of Novel 3-Substituted Poly(pyrroles) Bearing Crown-ether Moieties and a Study of their Electrochemical Properties

    Guernion, Nicolas J.L.; Blencowe, A.; Hayes, Wayne;

    2006-01-01

    A series of fourteen novel pyrrole monomers substituted at the 3-position with aliphatic and aromatic crown-ether moieties have been synthesised in good yield and characterised extensively. Several of those compounds were electropolymerised successfully in acetonitrile, using both potentiostatic ...

  10. Ion-Regulated Allosteric Binding of Fullerenes (C-60 and C-70) by Tetrathiafulvalene-Calix[4]pyrroles

    Davis, C. M.; Lim, J. M.; Larsen, K. R.;

    2014-01-01

    The effect of ionic species on the binding of fullerenes (C-60 and C-70) by tetrathiafulvalene-calix[4]pyrrole (TTF-C4P) receptors and the nature of the resulting supramolecular complexes (TTF-C4P + fullerene + halide anion + tetraalkylammonium cation) was studied in the solid state through single...... the C4P in a ball-and-socket binding mode. The interactions between the TTF-C4P receptors and the fullerene guests are highly influenced by both the nature of halide anions and their counter tetraalkylammonium cations. Three halides (F-, Cl-, and Br-) were studied. All three potentiate the binding of...... the two test fullerenes by inducing a conformational change from the 1,3-alternate to the cone conformer of the TTF-C4Ps, thus acting as positive heterotropic allosteric effectors. For a particular halide anion, the choice of tetraalkylammonium salts serves to modulate the strength of the TTF-C4P...

  11. Porous polypyrrole/polymethylmethacrylate composite film prepared by vapor deposition polymerization of pyrrole and its application for ammonia detection

    A simple method has been developed to fabricate porous polypyrrole/polymethyl methacrylate composite films. The synthesis procedures include the vapor deposition polymerization of pyrrole on the composite films of polymethyl methacrylate and ferric hydroxide bis(1,4-bis(2-ethylhexyl) sulfosuccinate), successively, washing the obtained composite films with methanol. Scanning electron microscopic and microscopic Raman spectral studies indicated that the pores had an average size of about 5 μm and they were uniformly dispersed in the whole films. The electrical conductivities of the composite films were measured to be in the range of 10-3 to 10-2 S cm-1. The porous composite films showed electroactivity, and the sensors based on them exhibited high sensitivity and fast response to ammonia gas

  12. Hemispherand-Strapped Calix[4]pyrrole: An Ion-pair Receptor for the Recognition and Extraction of Lithium Nitrite.

    He, Qing; Zhang, Zhan; Brewster, James T; Lynch, Vincent M; Kim, Sung Kuk; Sessler, Jonathan L

    2016-08-10

    The hemispherand-strapped calix[4]pyrrole (1) acts as an ion pair receptor that exhibits selectivity for lithium salts. In organic media (CD2Cl2 and CD3OD, v/v, 9:1), receptor 1 binds LiCl with high preference relative to NaCl, KCl, and RbCl. DFT calculations provided support for the observed selectivity. Single crystal structures of five different lithium ion-pair complexes of 1 were obtained. In the case of LiCl, a single bridging water molecule between the lithium cation and chloride anion was observed, while tight contact ion pairs were observed in the case of the LiBr, LiI, LiNO3, and LiNO2 salts. Receptor 1 proved effective as an extractant for LiNO2 under both model solid-liquid and liquid-liquid extraction conditions. PMID:27442768

  13. Design and modelling of enzyme/poly-pyrrole modified electrodes for bio-catalyzed electro-synthesis processes

    This research thesis reports a study which aims at developing, analyzing and integrating an electrode-enzyme interface within an electro-enzymatic reactor to develop electrochemical biosensors. The adopted method comprises a confinement of the enzyme at the electrode surface by means of an electro-formed poly-pyrrole film. The author reports an experimental and theoretical study of the coupling between electrochemical reaction, enzymatic reaction and matter transfer in the polymer in order to better understand the operation of so-modified electrodes. Different parameters have an influence on the reaction rate. A numerical model (validated by experiments) allows the identification of the reaction limiting stages. A new elaboration protocol allows the polymer permeability to be increased. The interface is first applied to the reduction of the NAD coenzyme, and the process is also applied to the production of gluconic acid

  14. Preparation and characterization of poly-pyrrole thin films functionalized by ion exchanger groups. Application to preparation of alpha sources

    After having outlined that dosing methods still present problems related to chemical separations techniques used before radioactivity measurements, and to spectrometric methods, this research thesis proposes the study of a new method of fabrication of a radioactive source. This method comprises the fabrication of a chemically reactive thin film by electro-polymerization, and the incorporation of actinides in the deposit by ion exchange. In this case, the deposit thickness could be controlled and the material transfer chemical mechanisms could be predicted and controlled

  15. Post Hartree–Fock and DFT Studies on Pyrrole···Nitrogen and Pyrrole···Carbon Monoxide Molecules

    P. Kolandaivel

    2002-07-01

    Full Text Available Abstract: The hydrogen bonded and van der Waals isomers of pyrrole···nitrogen and pyrrole···carbon monoxide have been studied using ab initio and density functional theory methods. Complex geometries and total energies of the isomers have been determined at HF, MP2, B3LYP and B3PW91 levels of theory employing 6-31G* basis set. For pyrrole···nitrogen complex, only two isomers have stable structure and the more stable one is found to be the hydrogen bonded isomer. Among the five isomers of pyrrole···carbon monoxide complex, the hydrogen bonded isomer is found to be the most stable form. The interaction energy for all these isomers have been calculated after eliminating the basis set superposition errors by using the full counterpoise correction method. Chemical hardness, chemical potential have been calculated and are used to study the stability of the molecules.

  16. 3-(Dicyanomethylidene)indan-1-one-Functionalized Calix[4]arene-Calix[4]pyrrole Hybrid: An Ion-Pair Sensor for Cesium Salts.

    Yeon, Yerim; Leem, Soojung; Wagen, Corin; Lynch, Vincent M; Kim, Sung Kuk; Sessler, Jonathan L

    2016-09-01

    A chromogenic calix[4]arene-calix[4]pyrrole hybrid ion pair receptor bearing an indane substituent at a β-pyrrolic position has been prepared. On the basis of solution-phase UV-vis spectroscopic analysis and (1)H NMR spectroscopic studies carried out in 10% methanol in chloroform, receptor 1 is able to bind only cesium ion pairs (e.g., CsF, CsCl, and CsNO3) but not the constituent cesium cation (as its perchlorate salt) or the F(-), Cl(-), or NO3(-) anions (as the tetrabutylammonium salts). It thus displays rudimentary AND logic gate behavior. Receptor 1 shows a colorimetric response to cesium ion pairs under conditions of solid-liquid (nitrobenzene) and liquid-liquid (D2O-nitrobenzene-d5) extraction. PMID:27533478

  17. Deproto-metallation of N-arylated pyrroles and indoles using a mixed lithium–zinc base and regioselectivity-computed CH acidity relationship

    Mohamed Yacine Ameur Messaoud

    2015-08-01

    Full Text Available The synthesis of N-arylated pyrroles and indoles is documented, as well as their functionalization by deprotonative metallation using the base in situ prepared from LiTMP and ZnCl2·TMEDA (1/3 equiv. With N-phenylpyrrole and -indole, the reactions were carried out in hexane containing TMEDA which regioselectively afforded the 2-iodo derivatives after subsequent iodolysis. With pyrroles and indoles bearing N-substituents such as 2-thienyl, 3-pyridyl, 4-methoxyphenyl and 4-bromophenyl, the reactions all took place on the substituent, at the position either adjacent to the heteroatom (S, N or ortho to the heteroatom-containing substituent (OMe, Br. The CH acidities of the substrates were determined in THF solution using the DFT B3LYP method in order to rationalize the experimental results.

  18. Silica sulfuric acid: a reusable solid catalyst for one pot synthesis of densely substituted pyrrole-fused isocoumarins under solvent-free conditions

    Sudipta Pathak

    2013-11-01

    Full Text Available A convenient and efficient methodology for the synthesis of densely substituted pyrrole-fused isocoumarins, which employs solid-supported silica sulfuric acid (SSA as catalyst, has been developed. When the mixture of ninhydrin adducts of acetylacetone/ethyl acetoacetate and primary amines was heated on the solid surface of SSA under solvent-free conditions, the pyrrole-fused isocoumarins were formed in good yields. This synthetic method has several advantages such as the employment of solvent-free reaction conditions without the use of any toxic reagents and metal catalysts, the ease of product isolation, the use of a recyclable catalyst, the low cost, the easy availability of the starting materials, and the excellent yields of products.

  19. Synthesis and phototoxicity of isomeric 7,9-diglutathione pyrrole adducts: Formation of reactive oxygen species and induction of lipid peroxidation

    Liang Ma

    2015-09-01

    Full Text Available Pyrrolizidine alkaloids (PAs are hepatotoxic, genotoxic, and carcinogenic in experimental animals. Because of their widespread distribution in the world, PA-containing plants are probably the most common poisonous plants affecting livestock, wildlife, and humans. Upon metabolism, PAs generate reactive dehydro-PAs and other pyrrolic metabolites that lead to toxicity. Dehydro-PAs are known to react with glutathione (GSH to form 7-GSH-(+/−-6,7-dihydro-7-hydroxy-1-hydroxymethyl-5H-pyrrolizine (7-GS-DHP in vivo and in vitro and 7,9-diGS-DHP in vitro. To date, the phototoxicity of GS-DHP adducts has not been well studied. In this study, we synthesized 7-GS-DHP, a tentatively assigned 9-GS-DHP, and two enantiomeric 7,9-diGS-DHP adducts by reaction of dehydromonocrotaline with GSH. The two 7,9-diGS-DHPs were separated by high performance liquid chromatography (HPLC and their structures were characterized by 1H nuclear magnetic resonance (NMR and 1H–1H correlation spectroscopy (COSY NMR spectral analysis. Photoirradiation of 7-GS-DHP, 9-GS-DHP, and the two 7,9-diGS-DHPs as well as dehydromonocrotaline, dehydroheliotrine, and the 7-R enantiomer of DHP (DHR, by UVA light at 0 J/cm2, 14 J/cm2, and 35 J/cm2 in the presence of a lipid, methyl linoleate, all resulted in lipid peroxidation in a light dose-responsive manner. The levels of lipid peroxidation induced by the two isomeric 7,9-diGS-DHPs were significantly higher than that by 7-GS-DHP and 9-GS-DHP. When 7,9-diGS-DHP was irradiated in the presence of sodium azide (NaN3, the level of lipid peroxidation decreased; lipid peroxidation was enhanced when methanol was replaced by deuterated methanol. These results suggest that singlet oxygen is a product induced by the irradiation of 7,9-diGS-DHP. When irradiated in the presence of superoxide dismutase (SOD, the level of lipid peroxidation decreased, indicating that lipid peroxidation is also mediated by superoxide. These results indicate that lipid

  20. 2,2′,5,5′-Tetramethyl-1,1′-(hexane-1,6-diyldi-1H-pyrrole

    Ana C. Santos

    2009-07-01

    Full Text Available The molecule of the title compound, C18H28N2, composed of two 2,5-dimethylpyrrole groups linked by a hexane chain, lies across a crystallographic inversion centre. The mean plane of the pyrrole ring is almost perpendicular to the mean plane of the central chain, making a dihedral angle of 89.09 (8°. The crystal structure is stabilized by intermolecular C—H...π interactions.

  1. Stereoselective self-sorting in the self-assembly of a Phe-Phe extended guanidiniocarbonyl pyrrole carboxylate zwitterion: formation of two diastereomeric dimers with significantly different stabilities.

    Rodler, Fabian; Sicking, Wilhelm; Schmuck, Carsten

    2011-07-28

    The 'dipeptide extended' guanidiniocarbonyl pyrrole carboxylate zwitterion GCP-Phe-Phe 1 forms stable dimers in DMSO. However, dimerization is highly stereoselective. Only homochiral dimers are formed and the (L,L)·(L,L) dimer (K(dim) > 10(5) M(-1)) is significantly more stable by a factor of 10(3) than the diastereomeric (D,L)·(D,L) dimer (K(dim) = 120 M(-1)). PMID:21670799

  2. Synthesis of new pyrrole, pyrazole, pyrimidine and pyrrolopyrimidine derivatives carrying a sulfonamide moiety of expected antitumor activity with studying the synergistic effect of γ-irradiation

    In a search for new cytotoxic agents with improved antitumor activity, some new pyrrole, pyrazole pyrimidine and pyrrolo[2,3-d] pyrimidine derivatives bearing sulfonamide moiety were synthesized. All the newly synthesized compound were subjected to in-vitro cytotoxic screening, also the synergism of the synthesized compounds with radiation was studies. These new compounds were docked in the active site of the carbonic anhydrase enzyme.

  3. Photocatalytic Degradation of Eosin Yellow Using Poly(pyrrole-co-aniline)-Coated TiO2/Nanocellulose Composite under Solar Light Irradiation

    Anirudhan, T. S.; Rejeena, S. R.

    2015-01-01

    The present study describes the feasibility of a novel adsorbent cum photocatalyst, poly(pyrrole-co-aniline)-coated TiO2/nanocellulose composite (P(Py-co-An)-TiO2/NCC), to remove eosin yellow (EY) from aqueous solutions. The removal of EY was investigated by batch adsorption followed by photocatalysis. The effect of various adsorption parameters like adsorbent dose, pH, contact time, initial concentration, and ionic strength has been optimized for treating effluents from the dye industry. Ads...

  4. Antitumor Activity of a 5-Hydroxy-1H-Pyrrol-2-(5H-One-Based Synthetic Small Molecule In Vitro and In Vivo.

    Yunyun Geng

    Full Text Available Alternative chemo-reagents are in great demand because chemotherapy resistance is one of the major challenges in current cancer treatment. 5-hydoxy-1H-pyrrol-2-(5H-one is an important N-heterocyclic scaffold that is present in natural products and medicinal chemistry. However, its antitumor activity has not been systematically explored. In this study, we screened a panel of 5-hydoxy-1H-pyrrol-2-(5H-one derivatives and identified compound 1d as possessing strong anti-proliferative activity in multiple cancer cell lines. Cell cycle analysis revealed that 1d can induce S-phase cell cycle arrest and that HCT116 was sensitive to 1d-induced apoptosis. Further analysis indicated that 1d preferentially induced DNA damage and p53 activation in HCT116 cells and that 1d-induced apoptosis is partly dependent on p53. Furthermore, we showed that 1d significantly suppressed tumor growth in xenograft tumor models in vivo. Taken together, our results suggest that 5-hydoxy-1H-pyrrol-2-(5H-one derivatives bear potential antitumor activity and that 1d is an effective agent for cancer treatment.

  5. Orange to black electrochromic behaviour in poly(2-(2-thienyl)-1H-pyrrole) thin films

    We have studied an electrochromic precursor, 2-(2-thienyl)-1H-pyrrole (1), using two improved procedures of the Trofimov reaction. Optimised stereochemical calculations at the B3LYP/6-311G* level showed almost equal s-cis and s-trans conformational populations in 1 with marked out-of-plane deviations of ca. 30o. Model calculations suggest that the predominant rotational conformation in undoped poly(1) would be s-trans with the essential out-of-plane deviations around the all three interheterocyclic bonds of ca. 25-30o. Monomer 1 exhibited two irreversible oxidation processes at +0.86 and +1.3 V corresponding to the oxidation of the pyrrole and thiophene rings, respectively. Orange to black electrochromic behaviour was found in ClO4- doped poly(1) thin films with colouring and bleaching times of 1.8 and 1.3 s, respectively. The colouration efficiency during the bleaching process was 233 cm2/C. The optical contrast at 450 nm was 19% and in the near-IR was 36%. The band-gap of poly(1) (1.6-1.7 eV) was found to be significantly lower than that of polypyrrole (2.85 eV) and polythiophene (2.3 eV) as a consequence of increased electron delocalisation in the system. Important differences in the morphology of doped and dedoped poly(1) films were observed by atomic-force microscopy (AFM). Doped poly(1) films showed a granular morphology with primary particles of 45-60 nm in size and an average surface roughness of 3.5 nm. On the other hand, dedoped poly(1) films showed interconnected aggregates of 65-90 nm in size as a consequence of particle fusion, with a surface roughness of 9.2 nm. In summary, poly(1) is a promising material for emerging flexible electrochromic devices such as displays and variable optical attenuators

  6. Preparation of thin {alpha}-particle sources using poly-pyrrole films functionalized by a chelating agent; Preparation de sources minces d'emetteurs alpha a l'aide de films de polypyrrole fonctionnalises par un ligand chelatant

    Mariet, C. [CEA Saclay, INSTN, Institut National des Sciences et Techniques Nucleaires, 91 - Gif-sur-Yvette (France); Universite Pierre et Marie Curie, 75 - Paris (France)

    2000-07-01

    This work takes place in the scope of analysis of the {alpha}-particle emitting elements U, Pu and Am present in compound environmental matrix like sols and sediments. The samples diversity and above all the {alpha}-ray characteristics require the analyst to implement a sequence of chemical steps in which the more restricting is the actinides concentration in a uniform and thin layer en allowing an accurately measure of alpha activity. On this account, we studied a new technique for radioactive sources preparation based on tow steps: preparation of a thin film as source support; incorporation of radioactive elements by a chelating extraction mechanism. The thin films were obtained through electro-polymerization of pyrrole monomer functionalized by an chelating ligand able to extract actinides from concentrated acidic solutions. Polymerization conditions of this monomer were perfected, then obtained films were characterized from a physico-chemical point of view. We point out their extracting properties were comparable to (retention capacity, distribution coefficient) to those of usual ion-exchange resins. The underscore of uranyl and americium nitrate complexes formed in the thin layer allowed to calculate the extraction constants in case acid extraction is negligible. Thanks to this results, the values of the coefficients distribution D{sub U} and D{sub Am} could be provided for all nitric solutions in which acid extraction is negligible. Optimal actinides retention conditions in the polymer were defined and used to settle a protocol for plutonium analysis in environmental samples. (author)

  7. Comparative neurotoxicity and pyrrole-forming potential of 2,5-hexanedione and perdeuterio-2,5-hexanedione in the rat

    DeCaprio, A.P.; Briggs, R.G.; Jackowski, S.J.; Kim, J.C.

    1988-01-01

    2,5-Hexanedione (2,5-HD), the neurotoxic metabolite of n-hexane, reacts with protein amines to form alkylpyrrole adducts. Pyrrolylation of neurofilament protein may be the initiating molecular event in 2,5-HD neuropathy. The present study compares the neurotoxic and pyrrole-forming potentials of 2,5-HD with those of perdeuterio-2,5-HD ((D10)-2,5-HD) in the rat. Due to a requirement for C-H bond breaking in the reaction mechanism, the latter derivative was expected to exhibit a primary isotope effect, thus forming the pyrrole at a slower rate. In vitro studies confirmed that (D10)-2,5-HD pyrrolylated protein at only one-third of the initial rate seen with native 2,5-HD. Prolonged incubation resulted in similar pyrrole concentrations with both derivatives. Adult, male Wistar rats were administered daily (5 days/week) ip doses of either 3.5 mmol 2,5-HD or (D10)-2,5-HD/kg/day for 17 days or 2.5 mmol/kg/day for 38 days. At termination, animals administered 2,5-HD and (D10)-2,5-HD exhibited 27 and 8% body weight loss, respectively. Moderate to severe hindlimb paralysis was present in the 2,5-HD groups while only mild effects were seen in (D10)-2,5-HD-dosed rats. Neuropathological changes were prominent in spinal cord sections from 2,5-HD-treated animals, while no effects were present in rats given the deuterated derivative. Pyrrole adduct concentrations in serum and axonal cytoskeletal proteins from 2,5-HD-treated animals were two- to threefold higher than in rats given equimolar doses of (D10)-2,5-HD. Levels of covalent crosslinking of axonal cytoskeletal proteins (assessed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis) appeared to correlate with pyrrole concentrations. Tissue concentrations of each diketone isomer were not significantly different, indicating similar uptake of native and deuterated 2,5-HD.

  8. Electropolymerization of pyrrole on oxidizable metal under high frequency ultrasound irradiation. Application of focused beam to a selective masking technique

    Et Taouil, A. [Institut UTINAM, UMR 6213 CNRS, Universite de Franche-Comte, 30 Avenue de l' observatoire, 25009 Besancon Cedex (France); Lallemand, F., E-mail: fabrice.lallemand@univ-fcomte.f [Institut UTINAM, UMR 6213 CNRS, Universite de Franche-Comte, 30 Avenue de l' observatoire, 25009 Besancon Cedex (France); Hallez, L.; Hihn, J-Y. [Institut UTINAM, UMR 6213 CNRS, Universite de Franche-Comte, 30 Avenue de l' observatoire, 25009 Besancon Cedex (France)

    2010-12-01

    A novel masking technique against polymer deposition based on High Intensity Focused Ultrasound (HIFU) irradiation was developed for the first time. With this in mind, a variety of background salts were tested. Sodium salicylate was found to be the most effective electrolytic medium for pyrrole sonoelectropolymerization on copper as it leads to a very efficient passivating oxide layer preventing copper dissolution while enabling polymer formation independently from sonication. In such a medium, high frequency ultrasound greatly refines surface structure, and a slight increase in doping level is observed. Finally, it was proved that focused ultrasound increases copper dissolution in sodium oxalate electrolyte while preventing polypyrrole deposition. A selected zone on the copper substrate was thus irradiated by the focused ultrasound beam to protect it from polymerization. In a second stage, a self-assembled monolayer was deposited on this polymer-free area to create a surface biphased substrate. This type of masking technique can be proposed as an interesting alternative to lithography as it is easier to carry out and allows chemical waste reduction.

  9. A pyrrole quinoline quinone glucose dehydrogenase biosensor based on screen-printed carbon paste electrodes modified by carbon nanotubes

    A carbon nanotube (CNT) modified biosensor based on oxygen-independent, pyrrole quinoline quinone glucose dehydrogenase (PQQ-GDH) for monitoring glucose was studied. The disposable amperometric biosensors based on screen-printed carbon paste electrodes are low cost and suitable for mass production. Potassium ferricyanide was immobilized on the surface of the electrodes as an electron mediator, which decreased the work potential. The biosensor showed a linear amperometric response to glucose from 1 to 35 mM, with a sensitivity of 31.0 µA mM−1 cm−2. Experimentally, the compositions of PQQ-GDH, potassium ferricyanide, CNTs and other components were evaluated and optimized. Only 2 µl of sample are needed for one test, and the response time of the sensor is 20 s. The characteristics of the biosensor were studied through cyclic voltammetry, and experimental results showed that the CNTs could facilitate the electron transfer between the enzyme and electrode surface significantly. Compared with the biosensor without carbon nanotube modification, the CNTs improved the sensitivity of the biosensor up to five times

  10. One electron vs. two electron electrochemical and chemical oxidation of electron-donor substituted diketo-pyrrolo-pyrroles

    Electrochemical and chemical (using FeCl3) oxidation reactions of a series of eight N,N′-dialkylated soluble diketo-pyrrolo-pyrrole dyes (DPPs) substituted by electron donating and/or electron withdrawing groups were investigated electrochemically and by UV–vis spectrometry and the results were rationalized by DFT calculations. Influence of substituents on HOMO and LUMO energies as well as on the electron transfer mechanism was followed. Destabilization of HOMO by two piperidino-substituents in 3,6-diphenyl-DPP 5 enabled to observe a potential inversion in electrochemical oxidation of this derivative, when a two-electron oxidation occurs leading directly to a dication, whereas other DPPs are oxidized first in a one-electron transfer to a radical cation. In chemical oxidation with FeCl3 the radical cation is produced by two mechanisms: either directly (standard reaction) or in the case of 5 by a comproportionation reaction of neutral molecule and its dication. Using mutual comparison of oxidation potentials and HOMO/LUMO energies a quite realistic limit of FeCl3 oxidation ability in acetonitrile was found

  11. Effect of non-electroactive additives on the early stage pyrrole electropolymerization on indium tin oxide electrodes

    Castro-Beltran, A. [Facultad de Ingeniería Mecánica y Eléctrica, Universidad Autónoma de Nuevo León, Ave. Pedro de Alba s/n, Ciudad Universitaria, C.P. 66451 San Nicolás de los Garza, N.L. (Mexico); Centro de Innovación Investigación y Desarrollo en Ingeniería y Tecnología (CIIDIT), Universidad Autónoma de Nuevo León, PIIT-Monterrey C.P. 66600 Apodaca, N.L. (Mexico); Dominguez, C.; Bahena-Uribe, D. [Centro Investigación en Ingeniería y Ciencias Aplicadas (CIICAp), Universidad Autónoma del Estado de Morelos, Av. Universidad 1001, Col. Chamilpa, C.P. 62209 Cuernavaca, Mor. (Mexico); Sepulveda-Guzman, S., E-mail: selene.sepulvedagz@uanl.edu.mx [Facultad de Ingeniería Mecánica y Eléctrica, Universidad Autónoma de Nuevo León, Ave. Pedro de Alba s/n, Ciudad Universitaria, C.P. 66451 San Nicolás de los Garza, N.L. (Mexico); Centro de Innovación Investigación y Desarrollo en Ingeniería y Tecnología (CIIDIT), Universidad Autónoma de Nuevo León, PIIT-Monterrey C.P. 66600 Apodaca, N.L. (Mexico); Cruz-Silva, R. [Research Center for Exotic NanoCarbon, Shinshu University, 4-17-1 Wakasato, Nagano 380-8553 (Japan)

    2014-09-01

    The use of non-electroactive additives during electrodeposition of conducting polymers has long been used to modify the properties of deposited films. These additives can improve the adhesion, and not only change the morphology and deposition rate but also modify the chemical composition of the electrodeposited polymer. Several compounds have been used to modify deposition of polypyrrole; however, there is no systematic study of these compounds. In this work, we comparatively studied several water soluble chemical compounds, a cationic polymer, an anionic polymer, a cationic surfactant, and an anionic surfactant during potentiostatic electrodeposition of polypyrrole. In order to study the effect of these compounds on the interface, where the electrochemical polymerization takes place, we used electrochemical impedance spectroscopy. The morphology during the initial stage of growth was studied by atomic force microscopy, whereas the resulting polypyrrole films were observed by scanning electron microscopy. - Highlights: • Early-stage polymerization polypyrrole particles on indium tin oxide (ITO). • Anionic additives promote pyrrole oxidation and polypyrrole film growth on ITO. • Cationic polyelectrolyte promotes adhesion between ITO and polypyrrole film. • Non-electroactive additives strongly influence polypyrrole nucleation on ITO.

  12. Sub-10 nm Platinum Nanocrystals with Size and Shape Control: Catalytic Study for Ethylene and Pyrrole Hydrogenation

    Tsung, Chia-Kuang; Kuhn, John N.; Huang, Wenyu; Aliaga, Cesar; Hung, Ling-I; Somorjai, Gabor A.; Yang, Peidong

    2009-03-02

    Platinum nanocubes and nanopolyhedra with tunable size from 5 to 9 nm were synthesized by controlling the reducing rate of metal precursor ions in a one-pot polyol synthesis. A two-stage process is proposed for the simultaneous control of size and shape. In the first stage, the oxidation state of the metal ion precursors determined the nucleation rate and consequently the number of nuclei. The reaction temperature controlled the shape in the second stage by regulation of the growth kinetics. These well-defined nanocrystals were loaded into MCF-17 mesoporous silica for examination of catalytic properties. Pt loadings and dispersions of the supported catalysts were determined by elemental analysis (ICP-MS) and H2 chemisorption isotherms, respectively. Ethylene hydrogenation rates over the Pt nanocrystals were independent of both size and shape and comparable to Pt single crystals. For pyrrole hydrogenation, the nanocubes enhanced ring-opening ability and thus showed a higher selectivity to n-butylamine as compared to nanopolyhedra.

  13. Research on interfacial polymerization of pyrrole assist with Span80 system

    Yang, Q. H.; Tu, Z. Y.; Zhao, N. Y.

    2016-07-01

    With assistance of surfactants, self-assembled Polypyrrole (PPy) film was prepared via oil / water interfacial polymerization. The chemical structure and morphologies of the obtained samples have been characterized by Fourier transform infrared (FT-IR) and Scanning Electron Microscope (SEM), respectively. The electrochemical performance recorded on an electrochemical workstation, mainly includes cyclic voltammetry (CV) tests. The prepared PPy film has its own extremely vesicular structures from results and indicates by using different concentration surfactant Span80. The PPy film prepared 25 °C with 3.32 g/L Span80 (surpass its critical micelle concentration) as a surfactant possess a supernal specific capacitance of 368.18 F/g at a scan rate 50 mV/s in 1 M NaNO3 aqueous solution at.

  14. 3He NMR studies on helium-pyrrole, helium-indole, and helium-carbazole systems: a new tool for following chemistry of heterocyclic compounds.

    Radula-Janik, Klaudia; Kupka, Teobald

    2015-02-01

    The (3)He nuclear magnetic shieldings were calculated for free helium atom and He-pyrrole, He-indole, and He-carbazole complexes. Several levels of theory, including Hartree-Fock (HF), Second-order Møller-Plesset Perturbation Theory (MP2), and Density Functional Theory (DFT) (VSXC, M062X, APFD, BHandHLYP, and mPW1PW91), combined with polarization-consistent pcS-2 and aug-pcS-2 basis sets were employed. Gauge-including atomic orbital (GIAO) calculated (3)He nuclear magnetic shieldings reproduced accurately previously reported theoretical values for helium gas. (3)He nuclear magnetic shieldings and energy changes as result of single helium atom approaching to the five-membered ring of pyrrole, indole, and carbazole were tested. It was observed that (3)He NMR parameters of single helium atom, calculated at various levels of theory (HF, MP2, and DFT) are sensitive to the presence of heteroatomic rings. The helium atom was insensitive to the studied molecules at distances above 5 Å. Our results, obtained with BHandHLYP method, predicted fairly accurately the He-pyrrole plane separation of 3.15 Å (close to 3.24 Å, calculated by MP2) and yielded a sizable (3)He NMR chemical shift (about -1.5 ppm). The changes of calculated nucleus-independent chemical shifts (NICS) with the distance above the rings showed a very similar pattern to helium-3 NMR chemical shift. The ring currents above the five-membered rings were seen by helium magnetic probe to about 5 Å above the ring planes verified by the calculated NICS index. PMID:25228253

  15. Metalloporphyrins with all the pyrrole nitrogens replaced with phosphorus atoms, MP(P){sub 4} (M = Sc, Ti, Fe, Ni, Cu, Zn)

    Kuznetsov, Aleksey E., E-mail: aleksey73kuznets@gmail.com

    2015-02-02

    Highlights: • First systematic DFT study of the MP(P){sub 4} compounds with increasing number of d-electrons. • Complete substitution of pyrrole nitrogens by P-atoms does not change the ground spin state. • Complete substitution of pyrrole nitrogens by P-atoms results in a bowl-like shape. • Significant stabilization of the MP(P){sub 4} LUMOs compared to the MP counterparts. • MP(P){sub 4} HOMO/LUMO gaps are smaller than the MP HOMO/LUMO gaps. - Abstract: We performed first systematic DFT study of the structures and electronic features (frontier orbitals energies, HOMO/LUMO and optical gaps, IPs and EAs) of the MP(P){sub 4} compounds, with increasing number of d-electrons: 3d{sup 1}4s{sup 2} (Sc) → 3d{sup 2}4s{sup 2} (Ti) → 3d{sup 6}4s{sup 2} (Fe) → 3d{sup 8}4s{sup 2} (Ni) → 3d{sup 10}4s{sup 1} (Cu) → 3d{sup 10}4s{sup 2} (Zn). We performed systematic comparison with the tetrapyrrole MP counterparts. Complete substitution of the pyrrole nitrogens by P-atoms does not change the calculated ground spin state of the compound. All the MP(P){sub 4} species adopt a bowl-like shape, compared to generally planar or slightly distorted shapes of their MP counterparts. Significant positive charge accumulates on P-atoms in MP(P){sub 4}. Positive charges on the metals in MP(P){sub 4} are noticeably lower than in the MP counterparts. The calculated MP(P){sub 4} HOMO/LUMO gaps and optical gaps are noticeably smaller than the corresponding gaps in their MP counterparts, which is explained by stabilization of the MP(P){sub 4} LUMOs.

  16. Metalloporphyrins with all the pyrrole nitrogens replaced with phosphorus atoms, MP(P)4 (M = Sc, Ti, Fe, Ni, Cu, Zn)

    Highlights: • First systematic DFT study of the MP(P)4 compounds with increasing number of d-electrons. • Complete substitution of pyrrole nitrogens by P-atoms does not change the ground spin state. • Complete substitution of pyrrole nitrogens by P-atoms results in a bowl-like shape. • Significant stabilization of the MP(P)4 LUMOs compared to the MP counterparts. • MP(P)4 HOMO/LUMO gaps are smaller than the MP HOMO/LUMO gaps. - Abstract: We performed first systematic DFT study of the structures and electronic features (frontier orbitals energies, HOMO/LUMO and optical gaps, IPs and EAs) of the MP(P)4 compounds, with increasing number of d-electrons: 3d14s2 (Sc) → 3d24s2 (Ti) → 3d64s2 (Fe) → 3d84s2 (Ni) → 3d104s1 (Cu) → 3d104s2 (Zn). We performed systematic comparison with the tetrapyrrole MP counterparts. Complete substitution of the pyrrole nitrogens by P-atoms does not change the calculated ground spin state of the compound. All the MP(P)4 species adopt a bowl-like shape, compared to generally planar or slightly distorted shapes of their MP counterparts. Significant positive charge accumulates on P-atoms in MP(P)4. Positive charges on the metals in MP(P)4 are noticeably lower than in the MP counterparts. The calculated MP(P)4 HOMO/LUMO gaps and optical gaps are noticeably smaller than the corresponding gaps in their MP counterparts, which is explained by stabilization of the MP(P)4 LUMOs

  17. Comparison of the resonance-enhanced multiphoton ionization spectra of pyrrole and 2,5-dimethylpyrrole: Building toward an understanding of the electronic structure and photochemistry of porphyrins

    Beames, Joseph M.; Nix, Michael G. D.; Hudson, Andrew J.

    2009-11-01

    The photophysical properties of porphyrins have relevance for their use as light-activated drugs in cancer treatment and sensitizers in solid-state solar cells. However, the appearance of their UV-visible spectra is usually explained inadequately by qualitative molecular-orbital theories. We intend to gain a better insight into the intense absorption bands, and excited-state dynamics, that make porphyrins appropriate for both of these applications by gradually building toward an understanding of the macrocyclic structure, starting with studies of smaller pyrrolic subunits. We have recorded the (1+1) and (2+1) resonance-enhanced multiphoton ionization (REMPI) spectra of pyrrole and 2,5-dimethylpyrrole between 25 600 cm-1 (390 nm) and 48 500 cm-1 (206 nm). We did not observe a (1+1) REMPI signal through the optically bright B12 (ππ ∗) and A11 (ππ ∗) states in pyrrole due to ultrafast deactivation via conical intersections with the dissociative A12 (πσ ∗) and B11 (πσ ∗) states. However, we did observe (2+1) REMPI through Rydberg states with a dominant feature at 27 432 cm-1 (two-photon energy, 54 864 cm-1) assigned to a 3d←π transition. In contrast, 2,5-dimethylpyrrole has a broad and structured (1+1) REMPI spectrum between 36 000 and 42 500 cm-1 as a result of vibronic transitions to the B12 (ππ ∗) state, and it does not show the 3d←π Rydberg transition via (2+1) REMPI. We have complemented the experimental studies by a theoretical treatment of the excited states of both molecules using time-dependent density functional theory (TD-DFT) and accounted for the contrasting features in the spectra. TD-DFT modeled the photochemical activity of both the optically dark π1σ∗ states (dissociative) and optically bright π1π∗ states well, predicting the barrierless deactivation of the B12 (ππ ∗) state of pyrrole and the bound minimum of the B12 (ππ ∗) state in 2,5-dimethylpyrrole. However, the quantitative agreement between vibronic

  18. Gliclazide impurity F: N-[(perhydro­cyclo­penta­[c]pyrrol-2-yl)amino­carbon­yl]-o-toluene­sulfonamide

    Di Wu; Xueyuan Wang; Dongying Pang; Wei Su; Yan Sun

    2012-01-01

    The title compound, C15H21N3O3S, is known to be an impurity of gliclazide [systematic name: N-(hexahydro-1H-cyclopenta[c]pyrrol-2-ylcarbamoyl)-4-methylbenzenesulfonamide], a sulfonylurea antidiabetic drug. Gliclazide has a p-tolyl group substituting the sulfonamide functionality, while the title molecule contains an o-tolyl group. Both five-membered fused rings adopt envelope conformations. In the crystal, N—H...O hydrogen bonds are formed between HN(C=O)NH groups, building centrosy...

  19. Synthesis of 5,6-dihydropyrrolo[2,1-a]isoquinolines featuring an intramolecular radical-oxidative cyclization of polysubstituted pyrroles, and evaluation of their cytotoxic activity.

    Reyes-Gutiérrez, Paul E; Camacho, José R; Ramírez-Apan, Maria Teresa; Osornio, Yazmin M; Martínez, Roberto

    2010-10-01

    A three-step protocol for the synthesis of 1,2,3,8,9-pentasubstituted-5,6-dihydropyrrolo[2,1-a]isoquinolines is described, using van Leusen's polysubstituted pyrrole construction followed by intramolecular radical-oxidative cyclization of the isoquinoline system. The cytotoxic activities of the dihydropyrroloisoquinolines were tested on six tumor cell lines. Preliminary structure-activity studies revealed the importance of the identity of the aromatic substituent at the C-2 position, particularly a phenyl, m-(amino) phenyl or m-(cyclohexylmethylpiperazinamide) phenyl substituent, for cytotoxic activity. PMID:20672155

  20. Structure and spectroscopic properties of N,S-coordinating 2-methylsulfanyl-N-[(1H-pyrrol-2-ylmethylidene]aniline methanol monosolvate

    D. Douglas Richards

    2015-10-01

    Full Text Available The reaction of pyrrole-2-carboxaldehyde and 2-(methylsulfanylaniline in refluxing methanol gave an olive-green residue in which yellow crystals of the title compound, C12H12N2S·CH3OH, were grown from slow evaporation of methanol at 263 K. In the crystal, hydrogen-bonding interactions link the aniline molecule and a nearby methanol solvent molecule. These units are linked by a pair of weak C—H...Omethanol interactions, forming inversion dimers consisting of two main molecules and two solvent molecules.

  1. Enhanced open-circuit voltage in polymer solar cells by dithieno[3,2-b:2 ',3 '-d]pyrrole N-acylation

    Vanormelingen, Wouter; KESTERS, Jurgen; Verstappen, Pieter; DRIJKONINGEN, Jeroen; KUDRJASOVA, Julija; Koudjina, Simplice; Liegéois, Vincent; Champagne, Benoît; Manca, Jean; Lutsen, Laurence; Vanderzande, Dirk; Maes, Wouter

    2014-01-01

    A series of low bandgap copolymers composed of N-acyl-substituted dithieno[3,2-b:2′,3′-d]pyrroles (DTPs) as the electron rich donor constituents (with various alkyl side chain patterns) combined with different electron deficient acceptor building blocks are developed for polymer solar cell applications. Due to the introduction of the N-acyl substituents, the HOMO energy levels of the push–pull copolymers decrease as compared to the N-alkyl-DTP analogues, resulting in an increased open-circuit...

  2. 1-Benzoyl-3-[3-cyano-8-methyl-4-(1-methyl-1H-pyrrol-2-yl-5,6,7,8-tetrahydroquinolin-2-yl]thiourea

    Abdullah M. Asiri

    2011-09-01

    Full Text Available In the N-substituted benzoylthiourea, C24H23N5OS, the benzoylthiourea unit is non-planar (r.m.s. deviation = 0.126 Å. The aliphatic part of the tetrahydroquinoline fused-ring system is disordered over two positions in a 0.592 (5:0.408 (5 ratio. The pyridine and pyrrole rings are twisted by 55.2 (1° in order to avoid crowding of their respective substituents. Pairs of molecules are linked by N—H...N hydrogen bonds, forming centrosymmetric dimers. Furthermore, an intramolecular N—H...O hydrogen bond stabilizes the molecular conformation.

  3. Structural evaluation of tandem hairpin pyrrole-imidazole polyamides recognizing human telomeres.

    Hirata, Akiyoshi; Nokihara, Kiyoshi; Kawamoto, Yusuke; Bando, Toshikazu; Sasaki, Asuka; Ide, Satoru; Maeshima, Kazuhiro; Kasama, Takeshi; Sugiyama, Hiroshi

    2014-08-13

    A polyamide containing N-methylpyrrole (Py) and N-methylimidazole (Im), designated PIPA, binds with high affinity and specificity to specific nucleotide sequences in the minor groove of double-helical DNA. Based on a recent report of the synthesis of PIPA for telomere visualization, the present paper focused on the size of the connecting part (hinge region) of two PIPA segments of the tandem hairpin PIPA, Dab(Im-Im-Py)-Py-Py-Py-Im-[Hinge]-Dab(Im-Im-Py)-Py-Py-Py-Im-βAla-NH(CH2)3N(CH3)-(CH2)3NH-[Dye]. The present paper also describes the characterization of binding by measuring the thermal melting temperature and surface plasmon resonance and by specific staining of telomeres (TTAGGG)n in human cells. Microheterogeneity was also investigated by high-resolution mass spectrometry. We found that the optimal compound as the hinge segment for telomere staining was [-NH(C2H4O)2(C2H4)CO-] with tetramethylrhodamine as the fluorescent dye. PMID:25036716

  4. A DFT Study of Pyrrole-Isoxazole Derivatives as Chemosensors for Fluoride Anion

    Shanshan Tang

    2012-09-01

    Full Text Available The interactions between chemosensors, 3-amino-5-(4,5,6,7-tetrahydro-1H-indol-2-ylisoxazole-4-carboxamide (AIC derivatives, and different anions (F Cl, Br, AcO, and H2PO4 have been theoretically investigated using DFT approaches. It turned out that the unique selectivity of AIC derivatives for F is ascribed to their ability of deprotonating the host sensors. Frontier molecular orbital (FMO analyses have shown that the vertical electronic transitions of absorption and emission for the sensing signals are characterized as intramolecular charge transfer (ICT. The study of substituent effects suggests that all the substituted derivatives are expected to be promising candidates for fluoride chemosensors both in UV-vis and fluorescence spectra except for derivative with benzo[d]thieno[3,2-b]thiophene fragment that can serve as ratiometric fluorescent fluoride chemosensor only.

  5. Ferrocene-Functionalized 4-(2,5-Di(thiophen-2-yl)-1H-pyrrol-1-yl)aniline: A Novel Design in Conducting Polymer-Based Electrochemical Biosensors

    Rukiye Ayranci; Dilek Odaci Demirkol; Metin Ak; Suna Timur

    2015-01-01

    Herein, we report a novel ferrocenyldithiophosphonate functional conducting polymer and its use as an immobilization matrix in amperometric biosensor applications. Initially, 4-(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl)amidoferrocenyldithiophosphonate was synthesized and copolymerized with 4-(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl)benzenamine at graphite electrodes. The amino groups on the polymer were utilized for covalent attachment of the enzyme glucose oxidase. Besides, ferrocene on the backbon...

  6. Conjugated and fluorescent polymer based on dansyl-substituted pyrrole prepared by electrochemical polymerization in acetonitrile containing boron trifluoride diethyl etherate

    Graphical abstract: - Highlights: • A fluorescent pyrrole derivative bearing a dansyl substituent (PyPDG) was synthesized. • PyPDG was electropolymerized onto ITO in (C4H9)4NBF4/CH3CN/BFEE mixed electrolyte. • The resulting polymer (PPyPDG) films displayed electrochromic behavior. • PPyPDG is a good green light emitter material. - Abstract: A fluorescent pyrrole derivative bearing a dansyl substituent was prepared by a simple synthetic route and electropolymerized onto Indium Tin Oxide (ITO) electrodes. The presence of the dansyl group in the monomer precursor prevents the electropolymerization in usual systems, such as (C4H9)4NBF4 in acetonitrile (CH3CN). For this reason, it was added 20% boron trifluoride diethyl etherate (BFEE) to this system, to achieve electropolymerization. The resulting poly[3-(N-pyrrolyl)propyl dansylglycinate] (PPyPDG) films displayed electrochromic behavior. Their color varied from greenish-yellow, in the neutral state, to greyish-green, in the oxidized state; moreover PPyPDG is a good green light emitter material. Therefore, PPyPDG films might be potentially applicable in displays and optoelectronic devices

  7. High content of pyridinic- and pyrrolic-nitrogen-modified carbon nanotubes derived from blood biomass for the electrocatalysis of oxygen reduction reaction in alkaline medium

    Graphical abstract: Display Omitted -- Highlights: •An ORR electrocatalyst was fabricated from blood biomass and carbon nanotube. •The N-CNT catalyst exhibits good ORR activity, methanol resistance and stability. •The pyrolysis process produces high contents of pyridinic and pyrrolic N species. •The pyridinic-N group may play more important role in the active sites for ORR. -- Abstract: Here we present a facile synthetic route to design nitrogen-doped nanostructured carbon-based electrocatalyst for oxygen reduction reaction (ORR) by the copyrolysis of blood biomass from pig and carbon nanotubes (CNTs) at high temperatures. The nitrogen-doped CNTs obtained at 800 °C not only results in excellent ORR activity with four-electron transfer selectivity in alkaline medium, but also exhibits superior methanol-tolerant property and long-term stability. It is confirmed that high-temperature pyrolysis processes can facilitate to produce higher contents of pyridinic- and pyrrolic-N binding groups in electrocatalysts, contributing to the enhancement of ORR performance in terms of onset potential, half-wave potential, and limited current density. We also propose that the planar-N configuration may be the active site that is responsible for the improved ORR electrocatalytic performance. The straight-forward and cheap synthesis of the active and stable electrocatalyst makes it a promising candidate for electrochemical power sources such as fuel cells or metal-air batteries

  8. Strikingly different luminescent properties arising from single crystals grown from solution or from the vapor phase in a diketo-pyrrolo-pyrrole analog

    Imoda, Tomohiko; Mizuguchi, Jin

    2007-10-01

    The title compound di-cyano-pyrrolo-pyrrole (DCPP) is an analog of diketo-pyrrolo-pyrrole (DPP) known as a red pigment on the market. Brilliant orange photoluminescence has been observed in crystals of DCPP recrystallized from solution (crystal I); whereas the luminescence was quite weak in single crystals grown from the vapor phase (crystal II). To elucidate the difference in luminescent properties, a series of structural analysis together with thermal analysis has been carried out on crystals I and II at -180 °C, RT, 150 °C, and 200 °C. However, no difference in structure is recognized between crystals I and II within the precision of the x-ray analysis. Nevertheless, a slight difference in sublimation temperature of about 5° is observed between crystals I and II. Since the sublimation temperature depends on the cohesion in the solid state and the cohesion, in turn, governs the extent of lattice vibration (i.e., nonradiative process), a slight difference in sublimation temperature appears to determine the fraction between the radiative and nonradiative processes in crystals I and II.

  9. Alternating copolymers of cyclopenta[2,1-b;3,4-b']dithiophene and Thieno[3,4-c]pyrrole-4,6-dione for high-performance polymer solar cells

    Li, Zhao; Du, Xiaomei; Scoles, Ludmila; Robertson, Gilles; Toll, Floyd; Ding, Jianfu [Institute for Chemical Process and Environmental Technology (ICPET), National Research Council of Canada (NRC), Ottawa, ON (Canada); Tsang, Sai-Wing; Zhang, Yanguang; Tao, Ye; Lu, Jianping [Institute for Microstructural Sciences (IMS), National Research Council of Canada (NRC), Ottawa, ON (Canada)

    2011-09-09

    A series of alternating copolymers of cyclopenta[2,1-b;3,4-b']dithiophene (CPDT) and thieno[3,4-c]pyrrole-4,6-dione (TPD) have been prepared and characterized for polymer solar cell (PSC) applications. Different alkyl side chains, including butyl (Bu), hexyl (He), octyl (Oc), and 2-ethylhexyl (EH), are introduced to the TPD unit in order to adjust the packing of the polymer chain in the solid state, while the hexyl side chain on the CPDT unit remains unchanged to simplify discussion. The polymers in this series have a simple main chain structure and can be synthesized easily, have a narrow band gap and a broad light absorption. The different alkyl chains on the TPD unit not only significantly influence the solubility and chain packing, but also fine tune the energy levels of the polymers. The polymers with Oc or EH group have lower HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital) energy levels, resulting higher open circuit voltages (V{sub oc}) of the PSC devices. Power conversion efficiencies (PCEs) up to 5.5% and 6.4% are obtained from the devices of the Oc substituted polymer (PCPDTTPD-Oc) with PC{sub 61}BM and PC{sub 71}BM, respectively. This side chain effect on the PSC performance is related to the formation of a fine bulk heterojunction structure of polymer and PCBM domains, as observed with atomic force microscopy. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  10. Catalytic mechanisms of direct pyrrole synthesis via dehydrogenative coupling mediated by PNP-Ir or PNN-Ru pincer complexes: Crucial role of proton-transfer shuttles in the PNP-Ir system

    Qu, Shuanglin

    2014-04-02

    Kempe et al. and Milstein et al. have recently advanced the dehydrogenative coupling methodology to synthesize pyrroles from secondary alcohols (e.g., 3) and β-amino alcohols (e.g., 4), using PNP-Ir (1) and PNN-Ru (2) pincer complexes, respectively. We herein present a DFT study to characterize the catalytic mechanism of these reactions. After precatalyst activation to give active 1A/2A, the transformation proceeds via four stages: 1A/2A-catalyzed alcohol (3) dehydrogenation to give ketone (11), base-facilitated C-N coupling of 11 and 4 to form an imine-alcohol intermediate (18), base-promoted cyclization of 18, and catalyst regeneration via H2 release from 1R/2R. For alcohol dehydrogenations, the bifunctional double hydrogen-transfer pathway is more favorable than that via β-hydride elimination. Generally, proton-transfer (H-transfer) shuttles facilitate various H-transfer processes in both systems. Notwithstanding, H-transfer shuttles play a much more crucial role in the PNP-Ir system than in the PNN-Ru system. Without H-transfer shuttles, the key barriers up to 45.9 kcal/mol in PNP-Ir system are too high to be accessible, while the corresponding barriers (<32.0 kcal/mol) in PNN-Ru system are not unreachable. Another significant difference between the two systems is that the addition of alcohol to 1A giving an alkoxo complex is endergonic by 8.1 kcal/mol, whereas the addition to 2A is exergonic by 8.9 kcal/mol. The thermodynamic difference could be the main reason for PNP-Ir system requiring lower catalyst loading than the PNN-Ru system. We discuss how the differences are resulted in terms of electronic and geometric structures of the catalysts and how to use the features in catalyst development. © 2014 American Chemical Society.

  11. Synthesis, characterization and conductivity studies of polypyrrole–fly ash composites

    M V Murugendrappa; Syed Khasim; M V N Ambika Prasad

    2005-10-01

    in situ polymerization of pyrrole was carried out in the presence of fly ash (FA) to synthesize polypyrrole–fly ash composites (PPy/FA) by chemical oxidation method. The PPy/FA composites have been synthesized with various compositions (10, 20, 30, 40 and 50 wt%) of fly ash in pyrrole. The surface morphology of these composites was studied with scanning electron micrograph (SEM). The polypyrrole–fly ash composites were also characterized by employing X-ray diffractometry (XRD) and infrared spectroscopy (IR). The a.c. conductivity behaviour has been investigated in the frequency range 102–106 Hz. The d.c. conductivity was studied in the temperature range from 40–200°C. The dimensions of fly ash in the matrix have a greater influence on the observed conductivity values. The results obtained for these composites are of greater scientific and technological interest.

  12. Schiff base functionalized Organopropylsilatranes: Synthesis and structural characterization

    Gurjaspreet Singh; Promila; Amandeep Saroa; Jandeep Singh; Raj Pal Sharm; V Ferretti

    2016-02-01

    Synthesis of Schiff bases linked to organopropylsilatranes were performed by condensation reaction of post-functionalized silatranes such as aminopropylsilatrane (4), aminopropyl-3,7,10-trimethylsilatrane (5) and N-substituted aminopropylsilatrane (10) with two different aldehydes viz. pyrrole-2-carboxaldehyde and 2-hydroxy-1-napthaldehyde. The resulting Schiff base substituted silatranes were well characterized by elemental analysis, spectroscopic studies [IR, (1H, 13C) NMR, and MS]. The structures of two silatranes were confirmed by single crystal X-ray diffraction analysis.

  13. Effects of Molecular Structure on Intramolecular Charge Carrier Transport in Dithieno [3,2-b: 2,3-d] Pyrrole-Based Conjugated Copolymers

    Yoshihito Honsho

    2012-01-01

    Full Text Available Intramolecular mobility of positive charge carriers in conjugated polymer films based on dithieno [2,3-b: 2,3-d] pyrrole (DTP is studied by time-resolved microwave conductivity (TRMC. A series of DTP homopolymer and copolymers combined with phenyl, 2,2-biphenyl, thiophene, 2,2-bithiophene, and 9,9-dioctylfluorene were synthesized by Suzuki-Miyaura and Yamamoto coupling reactions. Polymers containing DTP unit are reported to show high value of hole mobility measured by FET method, and this type of polymers is expected to have stable HOMO orbitals which are important for hole transportation. Among these copolymers, DTP coupled with 9,9-dioctylfluorene copolymer showed the highest charge carrier mobility as high as 1.7 cm2/Vs, demonstrating an excellent electrical property on rigid copolymer backbones.

  14. Emission and absorption of light in poly pyrrole synthesized by plasma; Emision y absorcion de luz en polipirrol sintetizado por plasma

    Enriquez, M.A.; Colin, E.; Olayo, M.G.; Cruz, G.J.; Ordonez, E. [ININ, A.P. 18-1027, 11801 Mexico D.F. (Mexico); Benavides, R. [Departamento de Procesos de Transformacion, CIQA, Blvd. Enrique Reyna 140, Saltillo, Coahuila (Mexico); Morales, J.; Olayo, R. [UAM-I, Apdo. Postal 55-534, Iztapalapa, D.F. (Mexico)]. e-mail: gcc@nuclear.inin.mx

    2007-07-01

    The poly pyrrole structure (PPy) consists of heterocyclic rings with conjugation that it depends on the intensity of the electric field applied during the synthesis, and its luminescence is related with the {pi}-{pi}{sup *} transitions of that conjugation. To irradiate with light of different wavelengths, the results indicate that the polymer absorbs in the interval from 290 to 700 nm and it emits between 450 and 470 nm. The basal conductivity of the polymers, without electromagnetic excitation, it was measured in 10{sup -15} S/cm, however, to interact with visible light it is increased approximately 10 times and when excite with UV light it is increased up to 3 magnitude orders. (Author)

  15. Cation Recognition: Novel Potentiometric PVC-Membrane Sensor based on Meso-octamethylcalix[4]pyrrole for the Determination of Trace Amounts of Titanium (III) Ions

    The present work deals with developing a novel high selective membrane electrode based on meso-octamethylcalix[4]pyrrole for accurate determination of trace amount of titanium (III) ions in real sample solutions. The amounts of ionophore (4 mg), PVC (33 mg), dioctyl phthalate (DOP) as plasticizer (62.8 mg) and sodium tetrakis [3,5-bis (trifluoromethyl) phenyl] borate (NaTFPB) as an ionic additive (0.2 mg) were optimized in the preparation of the membrane. The electrode exhibited a linear response with a near Nernstian slope of 29.49±0.16 (mV per decade of activity) over the pH range from 1 to 3 with a satisfactory concentration range of 1.0 x 10-6 to 1.0 x x10-2 M. The developed sensor exhibited good reproducibility over a period of about 3 months with a fast response time of 15 seconds. (author)

  16. Gamma irradiation effect on polymers derived of pyrrole synthesized by plasma; Efecto de irradiacion gamma en polimeros derivados de pirrol sintetizados por plasma

    Lopez G, O. G.

    2013-07-01

    This work studies the effect of gamma irradiation at doses of 50, 100, 200, 400 and 800 kGy on polymers obtained from pyrrole synthesized by plasma. The evolution of the structure was studied by Fourier transform infrared spectroscopy (Ftir) and X-ray photoelectron spectroscopy (XPS). The Ftir spectra show that poly pyrroles have N-H, C-H, C=O, triple and consecutive double bonds in their structure. The irradiated polymers show the same chemical groups in their structure without significant changes. Nevertheless, a more detailed analysis by XPS allows the identification of superficial chemical states, such as: C=CH-C, C=CC-C, C-NH-C, C-NC-C, etc., and shows that most of these states are present in all polymers but with different participation. One possible mechanism indicates that as the irradiation dose increases, dehydrogenation processes are performed increasing fragmentation, crosslinking and formation of multiple bonds. The fragmentation and thermal degradation were studied by thermogravimetric analysis, indicating that the loss of moisture and light compounds formed during gamma irradiation occurs in the firsts 100 grades C. The main degradation of all polymers occurs from 150 to 700 grades C, suggesting that the thermal stability is independent of the irradiation dose in the interval studied. Morphology was studied using scanning electron microscopy techniques. Before irradiation, the polymer presented a uniform and practically smooth surface, however, after gamma irradiation, the applied energy increased roughness and macro fragmentation. The roughness and functional groups on the surface reduced the contact angle with water as the irradiation dose increased. However, the polymers are hydrophilic, because for all doses that contact angle is smaller than 90 grades C. Electrical conductivity was calculated respect to temperature in the interval from 25 to 100 grades C. Conductivity increases with temperature and is slightly greater in the irradiated polymers

  17. Anticancer potential of pyrrole (1, 2, a) pyrazine 1, 4, dione, hexahydro 3-(2-methyl propyl) (PPDHMP) extracted from a new marine bacterium, Staphylococcus sp. strain MB30.

    Lalitha, P; Veena, V; Vidhyapriya, P; Lakshmi, Pragna; Krishna, R; Sakthivel, N

    2016-05-01

    Marine bacterium, strain MB30 isolated from the deep sea sediment of Bay of Bengal, India, exhibited antimicrobial activity against human pathogenic bacteria. Based on the 16S rRNA sequence homology and subsequent phylogenetic tree analysis, the strain MB30 was identified as Staphylococcus sp. The bioactive metabolite produced by the strain MB30 was purified through silica gel column chromatography and preparative HPLC. Purified metabolite was further characterized by FT-IR, LC-MS and NMR analyses. On the basis of spectroscopic data, the metabolite was identified as pyrrole (1, 2, a) pyrazine 1, 4, dione, hexahydro 3-(2-methyl propyl) (PPDHMP). The PPDHMP exhibited in vitro anticancer potential against lung (A549) and cervical (HeLa) cancer cells in a dose-dependent manner with the IC50 concentration of 19.94 ± 1.23 and 16.73 ± 1.78 μg ml(-1) respectively. The acridine orange (AO)/ethidium bromide (EB) and 4,6-diamidino-2-phenylindole dihydrochloride (DAPI) staining of the IC50 concentration of PPDHMP-treated cancer cells exhibited an array of morphological changes such as nuclear condensation, cell shrinkage and formation of apoptotic bodies. The PPDHMP-treated cancer cells induced the progressive accumulation of fragmented DNA in a time-dependent manner. Based on the flow cytometric analysis, it has become evident that the compound was also effective in arresting the cell cycle at G1 phase. Further, the Western blotting analysis confirmed the down-regulation of cyclin-D1, cyclin dependent kinase (CDK-2), anti-apoptotic Bcl-2 family proteins (Bcl-2 and Bcl-xL), activation of caspase-9 and 3 with the cleavage of PARP. The PPDHMP-treated cancer cells also showed the inhibition of migration and invasive capacity of cancer cells. In the present investigation, for the first time, we have reported the extraction, purification and characterization of an anticancer metabolite, PPDHMP from a new marine bacterium, Staphylococcus sp. strain MB30. PMID:26852140

  18. A convenient method for 14C-labeling of N-(2-oxo-5-phenyl-2,3-dihydro-1H-benzo[e] [1,4]diazepin-3-yl)-1H-pyrrole-2-carboxamide-[carboxy-14C] as CCK-A antagonist

    N-(2-oxo-5-phenyl-2,3-dihydro-1H-benzo[e] [1,4]diazepin-3-yl)-1H-pyrrole-2-carboxamide-[carboxy-14C] was prepared as part of a five-step sequence from pyrrol-2-carbonitrile-[cyano-14C] as a key synthetic intermediate which has been synthesized from 2-bromopyrrole and zinc [14C]-cyanide in the presence of tetrakis (triphenylphosphine)palladium. (author)

  19. Characterization of acid tars

    Acid tars from the processing of petroleum and petrochemicals using sulfuric acid were characterized by gas chromatography/mass spectrometry (GC/MS), inductively coupled plasma/optical emission spectrometry (ICP/OES), differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) spectrometry, and scanning electron microscopy/energy dispersive X-ray (SEM/EDX) micro-analysis. Leaching of contaminants from the acid tars in 48 h batch tests with distilled water at a liquid-to-solid ratio 10:1 was also studied. GC/MS results show that the samples contained aliphatic hydrocarbons, cyclic hydrocarbons, up to 12 of the 16 USEPA priority polycyclic aromatic hydrocarbons (PAHs), and numerous other organic groups, including organic acids (sulfonic acids, carboxylic acids and aromatic acids), phenyl, nitrile, amide, furans, thiophenes, pyrroles, and phthalates, many of which are toxic. Metals analysis shows that Pb was present in significant concentration. DSC results show different transition peaks in the studied samples, demonstrating their complexity and variability. FTIR analysis further confirmed the presence of the organic groups detected by GC/MS. The SEM/EDX micro-analysis results provided insight on the surface characteristics of the samples and show that contaminants distribution was heterogeneous. The results provide useful data on the composition, complexity, and variability of acid tars; information which hitherto have been scarce in public domain.

  20. Biocatalytic ammonolysis of (5S)-4,5-dihydro-1H-pyrrole-1,5-dicarboxylic acid, 1-(1,1-dimethylethyl)-5-ethyl ester: preparation of an intermediate to the dipeptidyl peptidase IV inhibitor Saxagliptin.

    Gill, Iqbal; Patel, Ramesh

    2006-02-01

    An efficient biocatalytic method has been developed for the conversion of (5S)-4,5-dihydro-1H-pyrrole-1,5-dicarboxylic acid, 1-(1,1-dimethylethyl)-5-ethyl ester (1) into the corresponding amide (5S)-5-aminocarbonyl-4,5-dihydro-1H-pyrrole-1-carboxylic acid, 1-(1,1-dimethylethyl)ester (2), which is a critical intermediate in the synthesis of the dipeptidyl peptidase IV (DPP4) inhibitor Saxagliptin (3). Candida antartica lipase B mediates ammonolysis of the ester with ammonium carbamate as ammonia donor to yield up to 71% of the amide. The inclusion of Ascarite and calcium chloride as adsorbents for carbon dioxide and ethanol byproducts, respectively, increases the yield to 98%, thereby offering an efficient and practical alternative to chemical routes which yield 57-64%. PMID:16257208

  1. Electronic, Spectral, and Electrochemical Properties of (TPPBr(x)())Zn Where TPPBr(x)() Is the Dianion of beta-Brominated-Pyrrole Tetraphenylporphyrin and x Varies from 0 to 8.

    D'Souza, Francis; Zandler, Melvin E.; Tagliatesta, Pietro; Ou, Zhongping; Shao, Jianguo; Van Caemelbecke, Eric; Kadish, Karl M.

    1998-09-01

    The electronic, spectral, and electrochemical characterization of (meso-tetraphenylporphyrinato)zinc(II) complexes bearing between 0 and 8 bromo substituents at the beta-pyrrole positions is reported. The investigated compounds are represented as (TPPBr(x)())Zn where TPPBr(x)() is the dianion of brominated 5,10,15,20-tetraphenylporphyrin and x varies between 0 and 8. Each porphyrin undergoes four well-defined one-electron transfer reactions to yield porphyrin pi-cation radicals and dications upon oxidation and porphyrin pi-anion radicals and dianions upon reduction. Half-wave potentials for the first reduction of (TPPBr(x)())Zn can be described by a single linear free energy relationship, and plots of E(1/2) versus the number of Br groups on the complex show a linear correlation with a positive slope of 63 mV per Br group. This is not the case for the other three electron transfer processes of the compounds where plots of E(1/2) versus the number of Br groups show distinctly different linear correlations for derivatives with 0-4 Br groups and those with 4-8 Br groups. The effect of increasing number of Br groups on the spectral and electrochemical properties of the neutral complexes was examined over the whole series of compounds, and these experimental results are compared to results of theoretical calculations by semiempirical molecular orbital AM1 methods using configurational interactions (CI) over the four Gouterman frontier pi-orbitals. The dihedral angle containing the four porphyrin macrocycle ring nitrogens is proposed as a measure of porphyrin ring nonplanarity, and this value increases with increasing number of Br substituents on (TPPBr(x)())Zn. Results of the AM1-CI = 4 calculations indicate that the spectrally determined HOMO-LUMO gap, i.e., the energy corresponding to the low-energy absorption band, varies in a nonlinear fashion with increasing number of Br substituents on the macrocycle and this is due to both the electronic effect of the

  2. 4-Hydroxy-7-oxo-5-heptenoic Acid (HOHA) Lactone is a Biologically Active Precursor for the Generation of 2-(ω-Carboxyethyl)pyrrole (CEP) Derivatives of Proteins and Ethanolamine Phospholipids

    Hua WANG; Linetsky, Mikhail; Guo, Junhong; Choi, Jaewoo; Hong, Li; Chamberlain, Amanda S.; Howell, Scott J.; Howes, Andrew M.; Robert G Salomon

    2015-01-01

    2-(ω-Carboxyethyl)pyrrole (CEP) derivatives of proteins were previously shown to have significant pathological and physiological relevance to age-related macular degeneration, cancer and wound healing. Previously, we showed that CEPs are generated in the reaction of ε-amino groups of protein lysyl residues with 1-palmityl-2-(4-hydroxy-7-oxo-5-heptenoyl)-sn-glycero-3-phosphatidylcholine (HOHA-PC), a lipid oxidation product uniquely generated by oxidative truncation of doco...

  3. A highly efficient group-assisted purification method for the synthesis of poly-functionalized pyrimidin-5-yl-pyrroles via one-pot four-component domino reaction.

    Dommaraju, Yuvaraj; Prajapati, Dipak

    2015-02-01

    A highly efficient, catalyst-free group-assisted purification chemical protocol for the construction of pyrimidine containing poly-functionalized pyrroles from a four-component domino reaction of acyclic-1,3-dicarbonyls or electron deficient alkynes, aromatic amines, barbituric acid and arylglyoxal hydrates under mild reaction conditions has been developed. The prominent features of the present protocol are environmentally benign, mild reaction conditions, atom economy, no column chromatography separation, easy isolation of products and excellent yields. PMID:25173493

  4. Thieno[3,2-b]- and thieno[2,3-b]pyrrole bioisosteric analogues of the hallucinogen and serotonin agonist N,N-dimethyltryptamine.

    Blair, J B; Marona-Lewicka, D; Kanthasamy, A; Lucaites, V L; Nelson, D L; Nichols, D E

    1999-03-25

    The synthesis and biological activity of 6-[2-(N, N-dimethylamino)ethyl]-4H-thieno[3,2-b]pyrrole (3a) and 4-[2-(N, N-dimethylamino)ethyl]-6H-thieno[2,3-b]pyrrole (3b), thienopyrroles as potential bioisosteres of N,N-dimethyltryptamine (1a), are reported. Hallucinogen-like activity was evaluated in the two-lever drug discrimination paradigm using LSD- and DOI-trained rats. Neither 3a nor 3b substituted for LSD or DOI up to doses of 50 micromol/kg. By comparison, 1a fully substituted in LSD-trained rats. However, 3a and 3b fully substituted for the 5-HT1A agonist LY293284 ((-)-(4R)-6-acetyl-4-(di-n-propylamino)-1,3,4, 5-tetrahydrobenz[c,d]indole). Both 3a and 3b induced a brief "serotonin syndrome" and salivation, an indication of 5-HT1A receptor activation. At the cloned human 5-HT2A receptor 3b had about twice the affinity of 3a. At the cloned human 5-HT2B and 5-HT2C receptors, however, 3a had about twice the affinity of 3b. Therefore, thiophene lacks equivalence as a replacement for the phenyl ring in the indole nucleus of tryptamines that bind to 5-HT2 receptor subtypes and possess LSD-like behavioral effects. Whereas both of the thienopyrroles had lower affinity than the corresponding 1a at 5-HT2 receptors, 3a and 3b had significantly greater affinity than 1a at the 5-HT1A receptor. Thus, thienopyrrole does appear to serve as a potent bioisostere for the indole nucleus in compounds that bind to the serotonin 5-HT1A receptor. These differences in biological activity suggest that serotonin receptor isoforms are very sensitive to subtle changes in the electronic character of the aromatic systems of indole compounds. PMID:10090793

  5. Scientific Opinion on Flavouring Group Evaluation 77, Revision 1 (FGE.77Rev1: Consideration of Pyridine, Pyrrole and Quinoline Derivatives evaluated by JECFA (63rd meeting structurally related to Pyridine, Pyrrole, Indole and Quinoline Derivatives evaluated by EFSA in FGE.24Rev2 (2013

    EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF

    2014-02-01

    Full Text Available The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to consider evaluations of flavouring substances assessed since 2000 by the Joint FAO/WHO Expert Committee on Food Additives (the JECFA, and to decide whether further evaluation is necessary, as laid down in Commission Regulation (EC No 1565/2000. The present consideration concerns a group of 22 pyridine, pyrrole and quinoline derivatives evaluated by the JECFA (63rd meeting. The revision of this consideration is made since additional toxicity data have become available for isoquinoline [FL-no: 14.001], pyrrole [FL-no: 14.041] and 2-acetylpyrrole [FL-no: 14.047]. The toxicity data on 2-acetylpyrrole should also cover 2-propionylpyrrole [FL-no: 14.068]. Further, additional genotoxicity data on 6-methylquinoline [FL-no: 14.042] have become available. The Panel concluded that for 6-methylquinoline [FL-no: 14.042], the new genotoxicity data did not clear the concern with respect to genotoxicity in vitro and accordingly the substance is not evaluated through the Procedure. For 18 substances [FL-no: 14.001, 14.004, 14.007, 14.030, 14.038, 14.039, 14.041, 14.047, 14.058, 14.059, 14.060, 14.061, 14.065, 14.066, 14.068, 14.071, 14.072 and 14.164] considered in this FGE, the Panel agrees with the JECFA conclusion, “No safety concern at estimated levels of intake as flavouring substances” based on the MSDI approach. For three substances [FL-no: 13.134, 14.045 and 14.046], additional toxicological data are still required. Besides the safety assessment of these flavouring substances, the specifications for the materials of commerce have also been evaluated, and the information is considered adequate for all the substances.

  6. Pyrrole and 2,5-heptanedione in the urine of rats and 2,5-heptanedione in the urine of man: analytical determination of excretion upon exposure to n-heptane; Pyrrole und 2,5-Heptandion im Urin der Ratte und 2,5-Heptandion im Urin des Menschen: Analytische Bestimmung der Ausscheidung nach Exposition gegn n-Heptan

    Stoermer, A.G.C.

    1997-09-01

    A method for quantifying levels of the neurotoxic metabolite 2,5-heptanedione in rats and man after experimental exposure to n-heptane was developed. It consisted in determining the quantity of 2,5-heptanedione excreted in urine and the relevant excretion kinetics. Moreover, the excretion of pyrrole in the urine of rats was measured. In the urine of non-exposed rats and man, a basic excretion of 2,5-heptanedione was measured, with the rates of excretion being 0.11 and 4.5 nmol per hour, respectively. This basic excretion of 2,5-heptanedione is assumed to have an endogenous cause. The quantitive investigation of the dose dependence of the excretion of 2,5-heptanedione and pyrrole in the urine of rats and of 2,5-heptanedione in the urine of man is a prerequisite for assessing the risk posed by n-heptane with a view to peripheral neuropathies. (orig./MG) [Deutsch] Ziel dieser Arbeit war die Entwicklung einer Methode zur Quantifizierung der Belastung von Ratte und Mensch mit dem neurotoxischen Metaboliten 2,5-Heptandion nach experimentellen Expositionen gegen n-Heptan. Dazu sollte jeweils die ausgeschiedene Menge und die zugehoerige Ausscheidungskinetik von 2,5-Heptandion im Urin bestimmt werden. Darueber hinaus sollte die Ausscheidung von Pyrrolen im Urin von Ratten gemessen werden. Im Urin von nicht exponierten Ratten und Menschen wurde eine Grundausscheidung von 2,5-Heptandion gefunden, wobei die Ausscheidungsraten jeweils 0,11 bzw. 4,5 nmol/h betrugen. Fuer die Grundausscheidung von 2,5-Heptandion wird ein endogener Ursprung angenommen. Die quantitativen Untersuchungen zur Dosisabhaengigkeit der Ausscheidung im Urin von 2,5-Heptandion und Pyrrolen bei der Ratte und von 2,5-Heptandion beim Menschen sind eine Grundvoraussetzung fuer eine Abschaetzung des Risikos von n-Heptan fuer periphere Neuropathien. (orig./MG)

  7. Fe nanoparticle tailored poly(N-methyl pyrrole) nanowire matrix: a CHEMFET study from the perspective of discrimination among electron donating analytes

    Back-gated chemically sensitive field effect transistor (CHEMFET) platforms have been developed with electrochemically synthesized poly(N-methyl pyrrole) nanowires by a templateless route. The nanowire matrix has been tailored with Fe nanoparticles to probe their effect in enhancing the sensing capabilities of the nanowire platform, and further to see if the inculcation of Fe nanoparticles is helpful to enhance the screening capability of the sensor among electron donating analytes. A noticeable difference in the sensing behaviour of the CHEMFET sensor was observed when it was exposed to three different analytes—ammonia, phosphine and carbon monoxide. FET transfer characteristics were instrumental in the corroboration of the experimental validations. The observations have been rationalized considering the simultaneous modulation of the work functions of Fe and polymeric material. The real time behaviour of the sensor shows that the sensor platform is readily capable of sensing the validated analytes at a ppb level of concentration with good response and recovery behaviour. The best response could be observed for ammonia with an Fe nanoparticle tailored polymeric matrix, with a sensitivity of ∼31.58% and excellent linearity (R2 = 0.985) in a concentration window of 0.05 ppm to 1 ppm. (paper)

  8. [Determination of ten pesticides of pyrazoles and pyrroles in tea by accelerated solvent extraction coupled with gas chromatography-tandem mass spectrometry].

    Xu, Dunming; Lu, Shengyu; Chen, Dajie; Lan, Jinchang; Zhang, Zhigang; Yang, Fang; Zhou, Yu

    2013-03-01

    An effective method was developed and applied to determine the residues of ten pesticides of pyrazoles and pyrroles in tea by accelerated solvent extraction coupled with gas chromatography-tandem mass spectrometry (ASE-GC-MS/MS). The samples were extracted with ethyl acetate-hexane (1:1, v/v) for 5 min at 1.03 x 10(7) Pa and 100 degree C for one cycle. Then, they were purified by Envi-Carb/PSA column, and eluted by ethyl acetate-hexane (1:1, v/v). The analytes were determined by GC-MS/MS and quantified by external standard method. The limits of quantification were 0.003 mg/kg for fenpyroximate, 0.001 mg/kg for fipronil-sulfide, 0.002 mg/kg for fipronil, 0.005 mg/kg for fipronil-sulfone, 0.002 mg/kg for chlorfenapyr, 0.006 mg/kg for flusilazole, 0.001 mg/kg for difenzoquat, 0.001 mg/kg for pyraflufen-ethyl, 0.000 3 mg/kg for tebufenpyrad and 0.005 mg/kg for tolfenpyrad. The results show that the proposed method is sensitive and accurate for the determination of the ten pesticide residues. PMID:23785993

  9. Pyrrole-Terminated Ionic Liquid Surfactant: One Molecule with Multiple Functions for Controlled Synthesis of Diverse Multispecies Co-Doped Porous Hollow Carbon Spheres.

    Li, Jian; Zhu, Wei; Ji, Jingwei; Wang, Peng; Lan, Yue; Gao, Ning; Yin, Xianpeng; Wang, Hui; Li, Guangtao

    2016-05-01

    Rationally and efficiently controlling chemical composition, microstructure, and morphology of carbon nanomaterials plays a crucial role in significantly enhancing their functional properties and expending their applications. In this work, a novel strategy for simultaneously controlling these structural parameters was developed on the base of a multifunctional precursor approach, in which the precursor not only serves as carbon source and structure-directing agent, but also contains two heteroatom doping sites. As exemplified by using pyrrole-terminated ionic liquid surfactant as such precursor, in conjunction with sol-gel chemistry this strategy allows for efficiently producing well-defined hollow carbon spheres with controlled microstructure and chemical compositions. Remarkably, the dual-doping sites in confined silica channels provide an exciting opportunity and flexibility to access various doped carbons through simply anion exchange or altering the used oxidative polymerization agent, especially the multispecies codoped materials by combination of the two doping modes. All the results indicate that the described strategy may open up a new avenue for efficiently synthesizing functional carbon materials with highly controllable capability. PMID:27093191

  10. Photocatalytic Degradation of Eosin Yellow Using Poly(pyrrole-co-aniline-Coated TiO2/Nanocellulose Composite under Solar Light Irradiation

    T. S. Anirudhan

    2015-01-01

    Full Text Available The present study describes the feasibility of a novel adsorbent cum photocatalyst, poly(pyrrole-co-aniline-coated TiO2/nanocellulose composite (P(Py-co-An-TiO2/NCC, to remove eosin yellow (EY from aqueous solutions. The removal of EY was investigated by batch adsorption followed by photocatalysis. The effect of various adsorption parameters like adsorbent dose, pH, contact time, initial concentration, and ionic strength has been optimized for treating effluents from the dye industry. Adsorption of EY reached maximum at pH 4.5 and complete removal of dye was achieved using 3.5 g/L of P(Py-co-An-TiO2/NCC. Adsorption equilibrium data were fitted with Langmuir and Fritz-Schlunder isotherm models and the kinetics of adsorption follows a second-order mechanism. The adsorption capacity of P(Py-co-An-TiO2/NCC was found to be 3.39 × 10−5 mol/g and reached equilibrium within 90 min. The photocatalytic degradation of adsorbed dye under sunlight was possible and about 92.3% of dye was degraded within 90 min. The reusability of P(Py-co-An-TiO2/NCC was also investigated. The results indicate that P(Py-co-An-TiO2/NCC is the best material for the wiping out of EY from aqueous solutions.