Cyclometalated Osmium鈥揂mine Electronic Communication through the p-Oligophenylene Wire

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• 作者：Jun-Jian Shen ; Jiang-Yang Shao ; Zhong-Liang Gong ; Yu-Wu Zhong
• 刊名：Inorganic Chemistry
• 出版年：2015
• 出版时间：November 16, 2015
• 年：2015
• 卷：54
• 期：22
• 页码：10776-10784
• 全文大小：660K
• ISSN：1520-510X

文摘

A series of bis-tridentate cyclometalated osmium complexes with a redox-active triarylamine substituent have been prepared, where the amine substituent is separated from the osmium ion by a p-oligophenylene wire of various lengths. X-ray crystallographic data of complexes 3(PF₆) and 4(PF₆) with three or four repeating phenyl units between the osmium ion and the amine substituent are presented. These complexes show two consecutive anodic redox couples between +0.1 and +0.9 V vs Ag/AgCl, with the potential splitting in the range of 300鈥?90 mV. A combined experimental and theoretical study suggests that, in the one-electron-oxidized state, the odd electron is delocalized for short congeners and localized on the osmium component for long congeners. The electronic coupling parameter (V_ab) was estimated by the Marcus鈥揌ush analysis. The distance dependence plot of ln(V_ab) versus the osmium鈥揳mine geometrical distance (R_ab) gives a negative linear relationship with a decay slope of 鈭?.19 脜^鈥?, which is slightly steeper with respect to the previously reported ruthenium鈥揳mine series with the same molecular wire. DFT calculations with the long-range-corrected UCAM-B3LYP functional gave more reasonable results for the osmium complexes with respect to those with UB3LYP.