Catalytic hydrogen evolution from a covalently linked dicobaloxime
Catalytic hydrogen evolution from a covalently linked dicobaloxime
复制标题
DOI：
10.1073/pnas.1118329109
复制
发表时间：
2012-07
期刊：
影响因子：
--
通讯作者：
Carolyn N. Valdez;J. Dempsey;B. Brunschwig;J. Winkler;H. Gray
中科院分区：
文献类型：
--
作者：
Carolyn N. Valdez;J. Dempsey;B. Brunschwig;J. Winkler;H. Gray
在乙腈溶液中，由八亚甲基双（乙二肟）连接的钴（III）单体单元的二钴肟催化对甲苯磺酸的质子还原，在-0.4 V（饱和甘汞电极）处的电催化波证明了这一点。从催化电流峰高（kapp = 1100 ± 70 M-1 s-1）测定析氢速率。电化学实验表明，没有显着的增强，从单体类似物的H2的演变率：实验速率定律是一阶催化剂和酸与以前的研究结果相似的单核钴肟。我们的工作表明，H2进化可能发生质子化的还原产生的CoIIH，而不是两个CoIIIH单位的均裂。
A dicobaloxime in which monomeric Co(III) units are linked by an octamethylene bis(glyoxime) catalyzes the reduction of protons from p-toluenesulfonic acid as evidenced by electrocatalytic waves at -0.4 V vs. the saturated calomel electrode (SCE) in acetonitrile solutions. Rates of hydrogen evolution were determined from catalytic current peak heights (kapp = 1100 ± 70 M-1 s-1). Electrochemical experiments reveal no significant enhancement in the rate of H2 evolution from that of a monomeric analogue: The experimental rate law is first order in catalyst and acid consistent with previous findings for similar mononuclear cobaloximes. Our work suggests that H2 evolution likely occurs by protonation of reductively generated CoIIH rather than homolysis of two CoIIIH units.