Chelate‐Thiolate‐Coordinate Ligands Modulating the Configuration and Electrochemical Property of Dinitrosyliron Complexes (DNICs) |
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| Authors: | Dr. Shih‐Wey Yeh Chih‐Wei Lin Bai‐Heng Liu Dr. Chih‐Chin Tsou Dr. Ming‐Li Tsai Prof. Wen‐Feng Liaw |
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| Affiliation: | Department of Chemistry and Frontier Research Center, of Fundamental and Applied Science of Matters, National Tsing Hua University, Hsinchu 30013 (Taiwan) |
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| Abstract: | As opposed to the reversible redox reaction ({Fe(NO)2}10 reduced‐form DNIC [(NO)2Fe(S(CH2)3S)]2? ( 1 )?{Fe(NO)2}9 oxidized‐form [(NO)2Fe(S(CH2)3S)]?), the chemical oxidation of the {Fe(NO)2}10 DNIC [(NO)2Fe(S(CH2)2S)]2? ( 2 ) generates the dinuclear {Fe(NO)2}9–{Fe(NO)2}9 complex [(NO)2Fe(μ‐SC2H4S)2Fe(NO)2]2? ( 3 ) bridged by two terminal [SC2H4S]2? ligands. On the basis of the Fe K‐edge pre‐edge energy and S K‐edge XAS, the oxidation of complex 1 yielding [(NO)2Fe(S(CH2)3S)]? is predominantly a metal‐based oxidation. The smaller S1‐Fe1‐S2 bond angle of 94.1(1)° observed in complex 1 (S1‐Fe1‐S2 88.6(1)° in complex 2 ), compared to the bigger bond angle of 100.9(1)° in the {Fe(NO)2}9 DNIC [(NO)2Fe(S(CH2)3S)]?, may be ascribed to the electron‐rich {Fe(NO)2}10 DNIC preferring a restricted bite angle to alleviate the electronic donation of the chelating thiolate to the electron‐rich {Fe(NO)2}10 core. The extended transition state and natural orbitals for chemical valence (ETS‐NOCV) analysis on the edt‐/pdt‐chelated {Fe(NO)2}9 and {Fe(NO)2}10 DNICs demonstrates how two key bonding interactions, that is, a Fe?S covalent σ bond and thiolate to the Fe d charge donation, between the chelating thiolate ligand and the {Fe(NO)2}9/10 core could be modulated by the backbone lengths of the chelating thiolate ligands to tune the electrochemical redox potential (E1/2=?1.64 V for complex 1 and E1/2=?1.33 V for complex 2 ) and to dictate structural rearrangement/chemical transformations (S‐Fe‐S bite angle and monomeric vs. dimeric DNICs). |
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| Keywords: | bioinorganic chemistry chelates dinitrosyl iron complexes nitric oxide |
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