Keggin type heteropolyacids was found to be an efficient and reusable catalyst for the synthesis of biologically active quinoxaline derivatives from the condensation of 1,2-diamine with 1,2-dicarbonyl compounds in exc...Keggin type heteropolyacids was found to be an efficient and reusable catalyst for the synthesis of biologically active quinoxaline derivatives from the condensation of 1,2-diamine with 1,2-dicarbonyl compounds in excellent yields in water. This method provides a new and efficient protocol in terms of small quantity of catalyst, a wide scope of substrates, and simple work-up procedure.展开更多
Polyethylene glycol(PEG) was found to be an effective catalyst for the condensation of 1,2-diamines with 1,2-dicarbonyl compounds to afford the corresponding quinoxaline derivatives in excellent yields under mild reac...Polyethylene glycol(PEG) was found to be an effective catalyst for the condensation of 1,2-diamines with 1,2-dicarbonyl compounds to afford the corresponding quinoxaline derivatives in excellent yields under mild reaction conditions.展开更多
A polyvinylpolypyrrolidone supported triflic acid was shown to be useful as a recyclable heterogeneous catalyst for the rapid and efficient synthesis of quinoxaline derivatives in good-to-excellent yields. The catalys...A polyvinylpolypyrrolidone supported triflic acid was shown to be useful as a recyclable heterogeneous catalyst for the rapid and efficient synthesis of quinoxaline derivatives in good-to-excellent yields. The catalyst is easily prepared, air-stable, reusable, and easily removed from the reaction mixtures.展开更多
In this study, Yb immobilized NaY zeolite catalyst（Yb/NaY） was obtained by a hydrothermal method and characterized by XRD, BET, FT-IR, ICP-AES, and NH3-TPD. The catalyst displayed good catalytic activity when applie...In this study, Yb immobilized NaY zeolite catalyst（Yb/NaY） was obtained by a hydrothermal method and characterized by XRD, BET, FT-IR, ICP-AES, and NH3-TPD. The catalyst displayed good catalytic activity when applied to the synthesis of quinoxalines via condensation of a-hydroxyketones with 1,2-diamines,and could be reused several times without any loss of catalytic activity.展开更多
6,7-Dialkoxy-2,3-diphenylquinoxaline based narrow band gap conjugated polymers, poly[2,7-（9-octyl-9H- carbazole）-alt-5,5-（5,8-di-2-thinenyl-（6,7-dialkoxy-2,3-diphenylquinoxaline））] （PCDTQ） and poly[2,7-（9,9-d...6,7-Dialkoxy-2,3-diphenylquinoxaline based narrow band gap conjugated polymers, poly[2,7-（9-octyl-9H- carbazole）-alt-5,5-（5,8-di-2-thinenyl-（6,7-dialkoxy-2,3-diphenylquinoxaline））] （PCDTQ） and poly[2,7-（9,9-dioctylfluorene）- alt-5,5-（5,8-di-2-thinenyl-（6,7-dialkoxy-2,3-diphenylquinoxaline））] （PFDTQ）, have been synthesized by Suzuki polycondensation. Their optical, electrochemical, transport and photovoltaic properties have been investigated in detail. Hole mobilities of PCDTQ and PFDTQ films spin coated from 1,2-dichlorobenzene （DCB） solutions are 1.0 X 10-4 and 4.1 X 10-4 cm2 V-1 s-l, respectively. Polymer solar cells were fabricated with the as-synthesized polymers as the donor and PC61BM and PC7 IBM as the acceptor. Devices based on PCDTQ：PC71BM （1：3） and PFDTQ：PC7 IBM （1：3） fabricated from DCB solutions demonstrated a power conversion efficiency （PCE） of 2.5% with a Voc of 0.95 V and a PCE of 2.5% with a Voof 0.98 V, respectively, indicating they are promising donor materials.展开更多
Two catalysts, alumina and manganese oxide supported on alumina, have been prepared by calcination and precipitation-impregnation methods, respectively. The catalysts are characterised by the following techniques： Br...Two catalysts, alumina and manganese oxide supported on alumina, have been prepared by calcination and precipitation-impregnation methods, respectively. The catalysts are characterised by the following techniques： Brunner-Emmett-Teller-N2 adsorption-desorption for sur- face area, temperature programmed desorption of NH3 and n-butyl amine back titration methods for surface acidity, powder X-ray diffraction for textural properties, and Fourier transform infrared spectroscopy for the anionic radicals. The catalytic activity has been determined under heterogeneous conditions in the condensation reaction between o-phenylenediamine and benzil. The product purity is checked by thin-layer chromatography and melting point. The products are also analysed by LC-MS and 1H-NMR techniques. The yields of the products have been found to be good and catalysts exhibited excellent recyclability. The effect of changing the reaction para- meters such as temperature, reaction time, amount of the catalyst, nature of solvent and molar ratio of reactants on the yield of the product has been studied. The surface acidity of the catalysts plays an important role in activating the reaction.展开更多
文摘Keggin type heteropolyacids was found to be an efficient and reusable catalyst for the synthesis of biologically active quinoxaline derivatives from the condensation of 1,2-diamine with 1,2-dicarbonyl compounds in excellent yields in water. This method provides a new and efficient protocol in terms of small quantity of catalyst, a wide scope of substrates, and simple work-up procedure.
基金supported by the Natural Science Foundation of China(No.20272047,20572086)the Gansu Natural Science Foundation of China(No.0308RJZA-100)Key Laboratory of Eco-Environment-Related Polymer Material(Northwest Normal University),Ministry of the Education of China
文摘Polyethylene glycol(PEG) was found to be an effective catalyst for the condensation of 1,2-diamines with 1,2-dicarbonyl compounds to afford the corresponding quinoxaline derivatives in excellent yields under mild reaction conditions.
基金supported by the Islamic Azad University,Ayatollah Amoli Branch
文摘A polyvinylpolypyrrolidone supported triflic acid was shown to be useful as a recyclable heterogeneous catalyst for the rapid and efficient synthesis of quinoxaline derivatives in good-to-excellent yields. The catalyst is easily prepared, air-stable, reusable, and easily removed from the reaction mixtures.
基金the National Natural Science Foundation of China (No. 20802052) for financial support
文摘In this study, Yb immobilized NaY zeolite catalyst（Yb/NaY） was obtained by a hydrothermal method and characterized by XRD, BET, FT-IR, ICP-AES, and NH3-TPD. The catalyst displayed good catalytic activity when applied to the synthesis of quinoxalines via condensation of a-hydroxyketones with 1,2-diamines,and could be reused several times without any loss of catalytic activity.
基金supported by the 973 Programs (2011CB935702 and 2009CB623603)the NSF of China(Nos. 20834006, 51003006 and 21161160443)the Fundamental Research Funds for the Central Universities
文摘6,7-Dialkoxy-2,3-diphenylquinoxaline based narrow band gap conjugated polymers, poly[2,7-（9-octyl-9H- carbazole）-alt-5,5-（5,8-di-2-thinenyl-（6,7-dialkoxy-2,3-diphenylquinoxaline））] （PCDTQ） and poly[2,7-（9,9-dioctylfluorene）- alt-5,5-（5,8-di-2-thinenyl-（6,7-dialkoxy-2,3-diphenylquinoxaline））] （PFDTQ）, have been synthesized by Suzuki polycondensation. Their optical, electrochemical, transport and photovoltaic properties have been investigated in detail. Hole mobilities of PCDTQ and PFDTQ films spin coated from 1,2-dichlorobenzene （DCB） solutions are 1.0 X 10-4 and 4.1 X 10-4 cm2 V-1 s-l, respectively. Polymer solar cells were fabricated with the as-synthesized polymers as the donor and PC61BM and PC7 IBM as the acceptor. Devices based on PCDTQ：PC71BM （1：3） and PFDTQ：PC7 IBM （1：3） fabricated from DCB solutions demonstrated a power conversion efficiency （PCE） of 2.5% with a Voc of 0.95 V and a PCE of 2.5% with a Voof 0.98 V, respectively, indicating they are promising donor materials.
文摘Two catalysts, alumina and manganese oxide supported on alumina, have been prepared by calcination and precipitation-impregnation methods, respectively. The catalysts are characterised by the following techniques： Brunner-Emmett-Teller-N2 adsorption-desorption for sur- face area, temperature programmed desorption of NH3 and n-butyl amine back titration methods for surface acidity, powder X-ray diffraction for textural properties, and Fourier transform infrared spectroscopy for the anionic radicals. The catalytic activity has been determined under heterogeneous conditions in the condensation reaction between o-phenylenediamine and benzil. The product purity is checked by thin-layer chromatography and melting point. The products are also analysed by LC-MS and 1H-NMR techniques. The yields of the products have been found to be good and catalysts exhibited excellent recyclability. The effect of changing the reaction para- meters such as temperature, reaction time, amount of the catalyst, nature of solvent and molar ratio of reactants on the yield of the product has been studied. The surface acidity of the catalysts plays an important role in activating the reaction.
