Mechanism of H2 Evolution from a Photogenerated Hydridocobaloxime
Mechanism of H2 Evolution from a Photogenerated Hydridocobaloxime
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DOI：
10.1021/ja109351h
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发表时间：
2010-12-01
影响因子：
15
通讯作者：
Gray, Harry B.
中科院分区：
文献类型：
--
作者：
Dempsey, Jillian L.;Winkler, Jay R.;Gray, Harry B.
质子从溴化萘酚的三重激发态转移到二氟硼基桥接的Co-I-丁二酮肟络合物，形成（CoH）-H-III，通过瞬态吸收监测。（CoH）-H-III形成的二级速率常数在（3.5-4.7）x 10（9）M-1 s（-1）的范围内，质子转移与光酸的激发态失活相耦合。（CoH）-H-III随后在溶液中被过量的Co-I-丁二酮肟还原以产生（CoH）-H-II（k（红色）= 9.2 × 10（6）M-1 s（-1）），然后将其质子化以产生Co-II-丁二酮肟和H-2。
Proton transfer from the triplet excited state of brominated naphthol to a difluoroboryl bridged Co-I-diglyoxime complex, forming (CoH)-H-III, was monitored via transient absorption. The second-order rate constant for (CoH)-H-III formation is in the range (3.5-4.7) x 10(9) M-1 s(-1), with proton transfer coupled to excited-state deactivation of the photoacid. (CoH)-H-III is subsequently reduced by excess Co-I-diglyoxime in solution to produce (CoH)-H-II (k(red) = 9.2 x 10(6) M-1 s(-1)), which is then protonated to yield Co-II-diglyoxime and H-2.