Insight into the Reactivity and Electronic Structure of Dinuclear Dinitrosyl Iron Complexes

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• 作者：Feng-Chun Lo ; Ya-Wen Li ; I-Jui Hsu ; Chien-Hong Chen ; Wen-Feng Liaw
• 刊名：Inorganic Chemistry
• 出版年：2014
• 出版时间：October 20, 2014
• 年：2014
• 卷：53
• 期：20
• 页码：10881-10892
• 全文大小：616K
• ISSN：1520-510X

文摘

A combination of N/S/Fe K-edge X-ray absorption spectroscopy (XAS), X-ray diffraction data, and density functional theory (DFT) calculations provides an efficient way to unambiguously delineate the electronic structures and bonding characters of Fe鈥揝, N鈥揙, and Fe鈥揘 bonds among the direduced-form Roussin鈥檚 red ester (RRE) [Fe₂(渭-SPh)₂(NO)₄]^{2鈥?/sup>(1) with {Fe(NO)₂}10-{Fe(NO)₂}10 core, the reduced-form RRE [Fe₂(渭-SPh)₂(NO)₄]鈭?/sup>(3) with {Fe(NO)₂}9-{Fe(NO)₂}10 core, and RRE [Fe₂(渭-SPh)₂(NO)₄] (4) with {Fe(NO)₂}9-{Fe(NO)₂}9 core. The major contributions of highest occupied molecular orbital (HOMO) 113伪/尾 in complex 1 is related to the antibonding character between Fe(d) and Fe(d), Fe(d), and S atoms, and bonding character between Fe(d) and NO(蟺*). The effective nuclear charge (Z_eff) of Fe site can be increased by removing electrons from HOMO to shorten the distances of Fe路路路Fe and Fe鈥揝 from 1 to 3 to 4 or, in contrast, to increase the Fe鈥揘 bond lengths from 1 to 3 to 4. The higher IR 谓_NO stretching frequencies (1761, 1720 cm鈥? (4), 1680, 1665 cm鈥? (3), and 1646, 1611, 1603 cm鈥? (1)) associated with the higher transition energy of N_1s 鈫捪?(NO) (412.6 eV (4), 412.3 eV (3), and 412.2 eV (1)) and the higher Z_eff of Fe derived from the transition energy of Fe_1s 鈫?Fe_3d (7113.8 eV (4), 7113.5 eV (3), and 7113.3 eV (1)) indicate that the N鈥揙 bond distances of these complexes are in the order of 1 > 3 > 4. The N/S/Fe K-edge XAS spectra as well as DFT computations reveal the reduction of complex 4 yielding complex 3 occurs at Fe, S, and NO; in contrast, reduction mainly occurs at Fe site from complex 3 to complex 1.}