排序方式: 共有74条查询结果,搜索用时 15 毫秒
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Philipp Gotico Bernard Boitrel Rgis Guillot Marie Sircoglou Annamaria Quaranta Zakaria Halime Winfried Leibl Ally Aukauloo 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(14):4552-4557
Inspired by nature's orchestra of chemical subtleties to activate and reduce CO2, we have developed a family of iron porphyrin derivatives in to which we have introduced urea groups functioning as multipoint hydrogen‐bonding pillars on the periphery of the porphyrinic ring. This structure closely resembles the hydrogen‐bond stabilization scheme of the carbon dioxide (CO2) adduct in the carbon monoxide dehydrogenase (CODH). We found that such changes to the second coordination sphere significantly lowered the overpotential for CO2 reduction in this family of molecular catalysts and importantly increased the CO2 binding rate while maintaining high turnover frequency (TOF) and selectivity. Entrapped water molecules within the molecular clefts were found to be the source of protons for the CO2 reduction. 相似文献
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Yang Gu Sean N. Natoli Zhennan Liu Douglas S. Clark John F. Hartwig 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(39):14092-14098
The selective functionalization of one C?H bond over others in nearly identical steric and electronic environments can facilitate the construction of complex molecules. We report site‐selective functionalizations of C?H bonds, differentiated solely by remote substituents, catalyzed by artificial metalloenzymes (ArMs) that are generated from the combination of an evolvable P450 scaffold and an iridium‐porphyrin cofactor. The generated systems catalyze the insertion of carbenes into the C?H bonds of a range of phthalan derivatives containing substituents that render the two methylene positions in each phthalan inequivalent. These reactions occur with site‐selectivity ratios of up to 17.8:1 and, in most cases, with pairs of enzyme mutants that preferentially form each of the two constitutional isomers. This study demonstrates the potential of abiotic reactions catalyzed by metalloenzymes to functionalize C?H bonds with site selectivity that is difficult to achieve with small‐molecule catalysts. 相似文献
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Noam Zion David A. Cullen Piotr Zelenay Prof. Lior Elbaz 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(6):2504-2510
Aerogels are fascinating materials that can be used for a wide range of applications, one of which is electrocatalysis of the important oxygen reduction reaction. In their inorganic form, aerogels can have ultrahigh catalytic site density, high surface area, and tunable physical properties and chemical structures—important features in heterogeneous catalysis. Herein, we report on the synthesis and electrocatalytic properties of an iron–porphyrin aerogel. 5,10,15,20-(Tetra-4-aminophenyl)porphyrin (H2TAPP) and FeII were used as building blocks of the aerogel, which was later heat-treated at 600 °C to enhance electronic conductivity and catalytic activity, while preserving its macrostructure. The resulting material has a very high concentration of atomically dispersed catalytic sites (9.7×1020 sites g−1) capable of catalyzing the oxygen reduction reaction in alkaline solution (Eonset=0.92 V vs. RHE, TOF=0.25 e− site−1 s−1 at 0.80 V vs. RHE). 相似文献
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《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(12):3377-3381
A ruthenium complex, porphyrin sensitizer, fullerene acceptor molecular pentad has been synthesized and a long‐lived hole–electron pair was achieved in aqueous solution by photoinduced multistep electron transfer: Upon irradiation by visible light, the excited‐state of a zinc porphyrin (1ZnP*) was quenched by fullerene (C60) to afford a radical ion pair, 1,3(ZnP.+‐C60.−). This was followed by the subsequent electron transfer from a water oxidation catalyst unit (RuII) to ZnP.+ to give the long‐lived charge‐separated state, RuIII‐ZnP‐C60.−, with a lifetime of 14 μs. The ZnP worked as a visible‐light‐harvesting antenna, while the C60 acted as an excellent electron acceptor. As a consequence, visible‐light‐driven water oxidation by this integrated photosynthetic model compound was achieved in the presence of sacrificial oxidant and redox mediator. 相似文献
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