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111.
Saikat Das Sharma 《合成通讯》2013,43(6):980-991
A simple, efficient, and environmentally benign method has been developed for the exclusive formation of biologically significant 2-aryl-1-arylmethyl-1H-benzimidazoles under the heterogeneous catalysis of Amberlite IR-120 in aqueous media in excellent yields. The catalyst is recyclable without loss of activity. 相似文献
112.
Three series of 2-(4′-alkoxybiphenyl-4-yl)-1H-benzimidazole derivatives (nM-x), which possessed 5-nitrobenzimidazole (nM-N series), benzimidazole (nM-H series) or 5-methylbenzimidazole (nM-M series) units at the end of the molecule, were synthesised and characterised by infrared, 1H- and 13C-nuclear magnetic resonance spectra, electrospray ionisation-mass spectrometry and elemental analysis. Their phase transition behaviour was investigated by differential scanning calorimetry, polarising optical microscopy and X-ray diffraction. All the compounds exhibited enantiotropic smectic mesophases with wide temperature domains for a carbon number in the alkoxy chain from 6 to 16, where the mesophase ranges were 14–91°C and 17–99°C during heating and cooling processes for the nM-N compounds, 7–25°C and 8–49°C for the nM-H compounds and 48–81°C and 52–85°C for the nM-M compounds, respectively. The effect of the length of alkoxy chain on mesomorphic properties was discussed. The nM-N and nM-M exhibited a much wider mesophase range whether during heating or cooling process than the corresponding nM-H series, especially for the longer terminal chain (n > 8), which indicated that the substituent in the benzimidazole moiety was helpful in increasing the mesophase stability. 相似文献
113.
Three novel metal-organic complexes with formulas [Ni(C9N2O2H7)2(CH3OH)2](1),[Zn(C9N2O2H7)2(H2O)2](2) and [Cd(C9N2O2H7)2(CH3OH)2](3) were synthesized by the reactions of Ni,Zn and Cd salts with ethyl 2-benzimidazolylacetate under hydrothermal conditions or layering technique,and characterized by single-crystal X-ray diffraction analysis,IR spec-troscopy,solid-state luminescent properties and thermogravimetric(TG) analysis.The crystal data for these three complexes are as follows:for 1,monoclinic,space group P21/c,a = 9.384(3),b = 9.634(3),c = 11.292(3) ,β = 95.787(5)°,V = 1015.7(5) 3,Z = 2,F(000) = 492,Dc = 1.547 Kg/m3,μ = 1.002 mm-1,the final R = 0.0451 and wR = 0.0900 for 1833 observed reflections with Ⅰ 2σ(Ⅰ);for 2,orthorhombic,space group Pbca,a = 10.031(4),b = 10.379(4),c = 17.525(7),V = 1824.6(12) 3,Z = 4,F(000) = 928,Dc = 1.645 Kg/m3,μ = 1.392 mm-1,the final R = 0.0452 and wR = 0.0996 for 1661 observed reflections with Ⅰ 2σ(Ⅰ);for 3,monoclinic,space group P21/c,a = 9.9114(13),b =10.4852(15),c = 10.4120(14) ,β = 108.453(5)°,V = 1026.4(2) 3,Z = 2,F(000) = 532,Dc = 1.705 Kg/m3,μ = 1.110 mm-1,the final R = 0.0322 and wR = 0.0805 for 1822 observed reflections with Ⅰ 2σ(Ⅰ).In the three complexes,the ethyl 2-benzimidazolylacetate shows the same chelating mode,and the adjacent units are interlinked into a two-dimensional layer through hydrogen-bonds(O-H···O,N-H···O). 相似文献
114.
Sneh K. Dogra 《Journal of luminescence》2006,118(1):45-60
Spectral characteristics of 2-(4′-amino-3-pyridyl)benzimidazole (4-A3PyBI) have been studied in different solvents, as well as at different acid or base concentrations using absorption, fluorescence excitation and fluorescence spectroscopy. Excited singlet state (S1) lifetimes for each species were measured using nanosecond time-dependent spectrofluorimeter. AM1 semi-empirical and density functional theoretical (DFT) calculations were performed on each species for the spectral assignment. From the above results it is concluded that 4-A3PyBI exists only in the amine form. First protonation occurs at pyridineN- atom and second protonation at the benzimidazole (BI)N- atom. When dication (DC) species is excited, two emission bands are observed, having the same fluorescence excitation spectra, suggesting the same ground state (S0) precursor. Short wavelength (SW) emission band is assigned to the π-π* transition and long wavelength (LW) emission to the charge transfer transition. First deprotonation in S0 state occurs from >N-H moiety, whereas in S1 state it is from -NH2 group. Monoanion (MA) so formed in S1 state is non-fluorescent. Dianion (DA) is formed by further deprotonating >N-H moiety in S1 state and it is fluorescent. pKa values were determined and discussed. 相似文献
115.
Abdesselam Benjelloun Pierre Lochon Alain Brembilla 《Journal of molecular catalysis. A, Chemical》1999,140(3):1390-223
The esterolytic activity of metal ion complexes of n-alkyl-2-hydroxymethylbenzimidazoles/Zn2+ towards p-nitrophenyl esters (picolinates and alkanoates) was investigated in the presence of an amphiphilic polymer, poly(1-hexadecyl-3-vinylpyridinium bromide), as a macromolecular matrix. The reaction rate constants obtained for the polymer hydrophobic microdomains were compared with those observed for the new conventional surfactant, 3-ethyl-1-hexadecylpyridinium bromide, chosen as the model of the repeat unit of the homopolymer. In both cases, the kinetic analysis indicated that the esterolysis reaction proceeds through the formation of an initial binary complex Ligand–Zn2+, the stoichiometry of which is 2/1 type. 相似文献
116.
Ji‐Ye Kang Soo‐Mi Eo In‐Yup Jeon Yeong Suk Choi Loon‐Seng Tan Jong‐Beom Baek 《Journal of polymer science. Part A, Polymer chemistry》2010,48(5):1067-1078
The AB‐monomer, 3,4‐diaminobenzoic acid dihydrochloride, was recrystallized from an aqueous hydrochloric acid solution and used to synthesize high‐molecular‐weight poly(2,5‐benzimidazole) (ABPBI). ABPBI/carbon nanotube (CNT) composites were prepared via in situ polymerization of the AB‐monomer in the presence of single‐walled carbon nanotube (SWCNT) or multiwalled carbon nanotube (MWCNT) in a mildly acidic polyphosphoric acid. The ABPBI/SWCNT and ABPBI/MWCNT composites displayed good solubility in methanesulfonic acid and thus, uniform films could be cast. The morphology of these composite films was studied by X‐ray diffraction, scanning electron microscopy, transmission electron microscopy, and atomic force microscopy. The results showed that both types of CNTs were uniformly dispersed into the ABPBI matrix. Tensile properties of the composite films were significantly improved when compared with ABPBI, and their toughness (~200 MPa) was close to the nature's toughest spider silk (~215 MPa). The electrical conductivities of ABPBI/SWCNT and ABPBI/MWCNT composite films were 9.10 × 10?5 and 2.53 × 10?1 S/cm, respectively, whereas that of ABPBI film was 4.81 × 10?6 S/cm. These values are ~19 and 52,700 times enhanced by the presence of SWCNT and MWCNT, respectively. Finally, without acid impregnation, the ABPBI film was nonconducting while the SWCNT‐ and MWCNT‐based composites were proton conducting with maximum conductivities of 0.018 and 0.017 S/cm, respectively. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1067–1078, 2010 相似文献
117.
118.
A new tridentate benzimidazole derivative, 2,6-bis (benzo[1,2-d:4,5-d′]diimidazole-2′-yl) -pyridine (Bzdiimpy),was prepared from o-phenylenediamine in five steps with improved methods according to the literature in good yield.The crystal structure was determined by X-ray diffraction analysis. It crystallized in monoclinic, space group P21/c,with a=1.1708(4) nm, b=2.4796(9) nm, c=1.215 9(4) nm,β=114.641(7)°, Z=1, R=0.035 0, wR2=0.0890. The bzdiimp molecule displayed an almost planar structure and formed a zig-zag chain through weak interactions between imidazole-N and [SnCl6]2--Cl. Its electronic absorption and emission spectra were measured and compared with the reported analogue 2,6-bis (benz[1,2-d:4,5-d′]imidazole-2′-yl)-pyridine (Bzp). 相似文献
119.
P. G. Morozov S. V. Kurbatov F. M. Dolgushin M. Yu. Antipin L. P. Olekhnovich 《Russian Chemical Bulletin》2004,53(9):2071-2074
The reactions of 2-(2-aminophenyl)benzimidazole with substituted isatins afforded the corresponding 5,6-dihydrospiro(benz[4,5]imidazo[1,2-c]quinazoline-6,3indolin)-2-ones. The spirocyclic structure of the reaction products was established by NMR spectroscopy and X ray diffraction analysis.Results of the study were presented at the International Conference Modern Trends in Organoelement and Polymer Chemistry dedicated to the 50th anniversary of the A. N. Nesmeyanov Institute of Organoelement Compounds of the Russian Academy of Sciences (May 30–June 4, 2004, Moscow).Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1987–1989, September, 2004. 相似文献
120.