Abstract
In addition to probing the formation of dinitrosyl iron complexes (DNICs) by the characteristic Fe K-edge pre-edge absorption energy ranging from 7113.4 to 7113.8 eV, the distinct S K-edge pre-edge absorption energy and pattern can serve as an efficient tool to unambiguously characterize and discriminate mononuclear DNICs and dinuclear DNICs containing bridged-thiolate and bridged-sulfide ligands. The higher Fe-S bond covalency modulated by the stronger electron-donating thiolates promotes the Fe → NO π-electron back-donation to strengthen the Fe-NO bond and weaken the NO-release ability of the mononuclear DNICs, which is supported by the Raman ν(Fe-NO) stretching frequency. The Fe-S bond covalency of DNICs further rationalizes the binding preference of the {Fe(NO)2} motif toward thiolates following the trend of [SEt]- > [SPh]- > [SC7H 4SN]-. The relative d-manifold energy derived from S K-edge XAS as well as the Fe K-edge pre-edge energy reveals that the electronic structure of the {Fe(NO)2}9 core of the mononuclear DNICs [(NO)2Fe(SR)2]- is best described as {Fe III(NO-)2}9 compared to [{Fe III(NO-)2}9-{Fe III(NO-)2}9] for the dinuclear DNICs [Fe2(μ-SEt)(μ-S)(NO)4]- and [Fe 2(μ-S)2(NO)4]2-.
Original language | English |
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Pages (from-to) | 5396-5406 |
Number of pages | 11 |
Journal | Inorganic Chemistry |
Volume | 50 |
Issue number | 12 |
DOIs | |
Publication status | Published - 2011 Jun 20 |
All Science Journal Classification (ASJC) codes
- Physical and Theoretical Chemistry
- Inorganic Chemistry