Reactivity of a Series of Isostructural Cobalt Pincer Complexes with CO2, CO, and H+
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- 作者：David W. Shaffer ; Samantha I. Johnson ; Arnold L. Rheingold ; Joseph W. Ziller ; William A. Goddard ; III ; Robert J. Nielsen ; Jenny Y. Yang
- 刊名：Inorganic Chemistry
- 出版年：2014
- 出版时间：December 15, 2014
- 年：2014
- 卷：53
- 期：24
- 页码：13031-13041
- 全文大小：606K
- ISSN：1520-510X
文摘
The preparation and characterization of a series of isostructural cobalt complexes [Co(t-Bu)2PEPyEP(t-Bu)2(CH3CN)2][BF4]2 (Py = pyridine, E = CH2, NH, O, and X = BF4 (1a鈥?b>c)) and the corresponding one-electron reduced analogues [Co(t-Bu)2PEPyEP(t-Bu)2(CH3CN)2][BF4]2 (2a鈥?b>c) are reported. The reactivity of the reduced cobalt complexes with CO2, CO, and H+ to generate intermediates in a CO2 to CO and H2O reduction cycle are described. The reduction of 1a鈥?b>c and subsequent reactivity with CO2 was investigated by cyclic voltammetry, and for 1a also by infrared spectroelectrochemistry. The corresponding CO complexes of (2a鈥?b>c) were prepared, and the Co鈥揅O bond strengths were characterized by IR spectroscopy. Quantum mechanical methods (B3LYP-d3 with solvation) were used to characterize the competitive reactivity of the reduced cobalt centers with H+ versus CO2. By investigating a series of isostructural complexes, correlations in reactivity with ligand electron withdrawing effects are made.