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991.
Bomin Feng Xiuju Wu Ling Li Wei Gao Dr. Weihua Hu Prof. Chang Ming Li 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(49):11560-11565
It remains challenging to rationally synthesize iron/nitrogen-doped carbon (Fe/N-C) catalysts with rich Fe−Nx atomic active sites for improved oxygen reduction reaction (ORR) electrocatalysis. A highly efficient Fe/N-C catalyst, which has been synthesized through a spatial isolation strategy, is reported. Derived from bioinspired polydopamine (PDA)-based hybrid microsphere precursors, it is a multifunctional carrier that loads atomically dispersed Fe3+/Zn2+ ions through coordination interactions and N-rich melamine through electrostatic attraction and covalent bonding. The Zn2+ ions and melamine in the precursor efficiently isolate Fe3+ atoms upon pyrolysis to form rich Fe−Nx atomic active sites, and generate abundant micropores during high-temperature treatment; as a consequence, the resultant Fe-N/C catalyst contains rich catalytically active Fe−Nx sites and a hierarchical porous structure. The catalyst exhibits improved ORR activity that is superior to and close to that of Pt/C in alkaline and acidic solutions, respectively. 相似文献
992.
Wentong Gao Jianwei Xu Pengfei Zuo Hao Dong Yiwu Quan Pengshan Chang 《Journal of polymer science. Part A, Polymer chemistry》2019,57(13):1460-1466
The dynamic chemistry of disulfide bonds has emerged as one of the most powerful tools used for the fabrication of organic compounds and self‐healing materials. In this article, a novel aromatic amine‐terminated polysulfide oligomer is first synthesized from thiol‐terminated polysulfide oligomer and bis(4‐aminophenyl) disulfide via disulfide metathesis mechanism. The resulting oligomer is confirmed by FTIR and 1H NMR spectra and then successfully applied in constructing self‐healable polyurea material (A‐LP23‐I), which combines the advantages of higher strength of polyureas and excellent self‐healing ability of polysulfide‐based materials. After subjecting to a temperature of 75 °C for 48 h, both the tensile strength and ultimate elongation of A‐LP23‐I restore to more than 90% of the original values (3.32 MPa and 396%). This study demonstrates a novel strategy for synthesizing aromatic amine‐terminated oligomer. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 1460–1466 相似文献
993.
Wu Bin Lyu Pin Wang Kaixuan Qiu Xiaoyan Liu Taifeng Zhang Fang Li Hexing Xiao Shengxiong 《Research on Chemical Intermediates》2018,44(10):6327-6337
Research on Chemical Intermediates - Upon oxidation, a graphyne-like porous carbon-rich network (GYLPC), which is a two-dimensional carbon material consisting of sp- and sp2-hybridized carbon atoms... 相似文献
994.
995.
The enhanced biological activities of three Zn (II) complexes based on different 1,2,4‐triazole fungicides
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Guo‐yu Ren Jie Li Xu‐zhan Wei Jin‐hua Zhou Biao Yan Zhao‐qi Guo Ying‐hui Ren Xiao‐hong Sun Hai‐xia Ma 《应用有机金属化学》2018,32(9)
In order to screen effective fungicides, three Zn (II) complexes, [Zn L 1 4 (NO3)2]·2H2O·2EtOH ( 1 ), [Zn L 2 4 (NO3)2] ( 2 ), and [Zn L 3 4 (DMF)2](NO3)2 ( 3 ), ( L 1 = paclobutrazol, L 2 = diniconazole, and L 3 = hexaconazole), were synthesized and characterized by elemental analysis, FT‐IR spectroscopy, and single‐crystal XRD. The antifungal activities of these complexes were then evaluated against four selected fungi using the mycelial growth rate method. The resulting data indicate that all the complexes show the enhanced antifungal activities than the corresponding ligand and mixtures. And, the interactions between the metal salt and ligands in the three complexes seem to be synergistic. According to the study of the influence of the structures on the activity, complex 2 with C=C linkage and 2,4‐dichlorophenyl moieties enhances the bioactivity significantly, especially against Wheat gibberellic ( II ). Density functional theory (DFT) calculations were carried out to help explain the enhanced bioactivity of the Zn (II) complexes. Meanwhile, all complexes are excellent grow‐regulators, especially complex 3 . The resulting data show that the complexes based on triazole fungicides have the potential applications in agriculture. 相似文献
996.
Jong Min Park Chang Young Jung Joong Hyun Cho Dae Hyun Kim Yue Wang Jae Yun Jaung 《Tetrahedron letters》2018,59(35):3322-3325
New quinoxaline-based organic sensitizer bearing di-anchoring group for dye-sensitized solar cells (DSSCs) was synthesized from diethyl 4,5-diaminophthaltate, in which was prepared under mild condition by using Takehito’s method. The synthesized sensitizer was compared with mono-anchoring sensitizer through absorption spectra, emission spectra, J-V curve, and IPCE spectra, indicating the di-anchoring group leads to a noticeable improvement of Jsc value owing to more efficient intramolecular charge transfer and channel number increment. 相似文献
997.
Ethylene polymerization with long‐lifetime monopendant thienyl‐substituted group 4 metallocenes
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A series of group 4 metallocenes (RCp)[Cp―(bridge)―(2‐C4H3S)]MCl2 [M = Ti ( C1 , C2 , C3 , C4 ); M = Zr ( C5 , C6 , C7 , C8 )] bearing a pendant thiophene group on a cyclopentadienyl ring have been synthesized, characterized and tested as catalyst precursors for ethylene polymerization. The molecular structures of representative titanocenes C2 and C4 were confirmed by single‐crystal X‐ray diffraction and revealed that both complexes exist in an expected coordination environment for a monomeric bent metallocene. No intramolecular coordination between the thiophene group and the titanium center could be observed in the solid state. Upon activation by methylaluminoxane (MAO), titanocenes C1 , C2 , C3 , C4 showed moderate catalytic activities and produced high‐ or ultra‐high‐molecular‐weight polyethylene (Mv 70.5–227.1 × 104 g mol?1). Titanocene C3 is more active and long‐lived, with a lifetime of nearly 9 h at 30 °C. At elevated temperatures of 80–110 °C, zirconocenes C5 , C6 , C7 , C8 displayed high catalytic activities (up to 27.6 × 105 g PE (mol Zr)?1 h?1), giving high‐molecular‐weight polyethylene (Mv 11.2–53.7 × 104 g mol?1). Even at 80 °C, a long lifetime of at least 2 h was observed for the C8/MAO catalyst system. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
998.
Tie‐Qiang Huang Wen‐Yan Qu Jin‐Chang Ding Miao‐Chang Liu Hua‐Yue Wu Jiu‐Xi Chen 《Journal of heterocyclic chemistry》2013,50(2):293-297
A facile and simple catalyst‐free protocol has been developed for the condensation of 1,2‐diketones with aromatic 1,2‐diamines in polyethylene glycol (PEG), providing quinoxaline derivatives in good yields. The important features of the methodology are broad substrates scope, simple workup, catalyst free, environmentally benign, and no requirement for metal catalysts. It is noteworthy that the cyclization reaction of 1,2‐diketones with aliphatic 1,2‐diamines is also conducted smoothly to afford pyrazines in good yields under the standard conditions. In addition, PEG could be recovered easily and was reused without evident loss in activity 相似文献
999.
1000.
Computational insight into asymmetric uranyl‐salophen coordinated with α, β‐unsaturated aldehydes and ketones
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Wen‐Bo Lan Xiao‐Feng Wang Li‐Ping He Yan‐Bin Meng Jun Li Bin Qiu Chang‐Ming Nie 《应用有机金属化学》2018,32(3)
The study of the catalytic activity and activation mechanism of asymmetric uranyl‐salophens with α, β‐unsaturated aldehydes or α, β‐unsaturated ketones, is a research hotspot. In this paper, the complexes of the uranyl–salophen(U‐S) modified by unilateral benzene, coordinated with cyclohexenone, cyclopentenone and acrolein, were investigated using density functional theory calculations at the level of B3LYP/6‐311G(d, p) basis set. The results showed that the uranyl‐salophen(U‐S) weakened the large π bond between C = C and C = O of the α, β‐unsaturated aldehydes and ketones, making the unsaturated aldehydes and ketones activated. In addition, the molecular‐recognition selectivity of the asymmetrical uranyl‐salophen for cyclohexenone and cyclopentenone were much higher than for acrolein. 相似文献