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【應用科學系】恭賀李建明老師研究成果發表於美國化學學會Journal of the American Chemical Society - ACS Publications雜誌

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研究題目

Photoinduced NO and HNO Production from Mononuclear {FeNO}6 Complex Bearing a Pendant Thiol

研究人員

Chuan-Kuei Chiang, Kai-Ti Chu, Chia-Chin Lin, Shi-Rou Xie, Yu-Chiao Liu, Serhiy Demeshko, Gene-Hsiang Lee, Franc Meyer, Ming-Li Tsai, Ming-Hsi Chiang, and Chien-Ming Lee

摘要

Light triggers the formation of HNO from a metal−nitrosyl species, facilitated by an intramolecular pendant thiol proton. Two {FeNO}6 complexes (the Enemark−Felthan notation), [Fe(NO)(TMSPS2)(TMSPS2H)] (1TMSPS2H2 = 2,2’-dimercapto-3,3’-bis(trimethylsilyl)diphenyl)phenylphosphine; H is a dissociable proton) with a pendant thiol and [Fe(NO)(TMSPS2)(TMSPS2CH3)] (2) bearing a pendant thioether, are spectroscopically and structurally characterized. Both complexes are highly sensitive to visible light. Upon photolysis, complex 2 undergoes NO dissociation to yield a mononucle Fe(III) complex, [Fe(TMSPS2)(TMSPS2CH3)] (3).In contrast, the pendant SH of 1 can act as a trap for the departing NO radical upon irradiation, resulting in the formation of an intermediate A with an intramolecular [SH…ON-Fe] interaction. As suggested by computational results (DFT), the NO stretching frequency (νNO) is sensitive to the intramolecular interactionbetween the pendant ligand and the iron-bound NO, and a shift of nNO from 1833 (1) to 1823 cm−1 (A) is observed experimentally. Subsequentphotolysis of the intermediate A results in HNO production and a thiyl group that then coordinates to the Fe center for the formation of [Fe(TMSPS2)2] (4). In contrast to the common acid-base coupling pathway, the HNO is not voluntarily yielded from 1 but rather generated by the photo-promoted pathway. The photogenerated HNO can further react with [MnIII(TMSPS3)(DABCO)] (TMSPS3H3 = (2,2′,2″-trimercapto-3,3′,3″-tris(trimethylsilyl)triphenylphosphine; DABCO = 1,4-diazabicyclo[2.2.2]octane) in organic media to yield anionic [Mn(NO)(TMSPS3)] (5-) with a {MnNO}6 electronic configuration while [MnIII(TMSPS3)(DABCO)] reacts with NO gas for the formation of a {MnNO}5 species, [Mn(NO)(TMSPS3)] (6). Effective differentiation of the formation of HNO from the complex with the pendant SH vs. NO from that with the pendant SMe is achieved by the employment of [MnIII(TMSPS3)(DABCO)].

日期: 2019-07-05
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