Discrimination of mononuclear and dinuclear dinitrosyl iron complexes (DNICs) by S K-edge X-ray absorption spectroscopy: Insight into the electronic structure and reactivity of DNICs

Tsai Te Lu, Szu Hsueh Lai, Ya Wen Li, I. Jui Hsu, Ling Yun Jang, Jyh Fu Lee, I. Chia Chen, Wen Feng Liaw

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52 Citations (Scopus)

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 languageEnglish
Pages (from-to)5396-5406
Number of pages11
JournalInorganic Chemistry
Volume50
Issue number12
DOIs
Publication statusPublished - 2011 Jun 20

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

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