Transformation and Structural Discrimination between the Neutral {Fe(NO)2}10 Dinitrosyliron Complexes (DNICs) and the Anionic/Cationic {Fe(NO)2}9 DNICs

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• 作者：Mu-Cheng Hung ; Ming-Che Tsai ; Gene-Hsiang Lee ; and Wen-Feng Liaw
• 刊名：Inorganic Chemistry
• 出版年：2006
• 出版时间：July 24, 2006
• 年：2006
• 卷：45
• 期：15
• 页码：6041 - 6047
• 全文大小：126K
• 年卷期：v.45,no.15(July 24, 2006)
• ISSN：1520-510X

文摘

Reaction of Fe(CO)₂(NO)₂ and sparteine/tetramethylethylenediamine (TMEDA) in tetrahydrofuran afforded the electronparamagnetic resonance (EPR)-silent, neutral {Fe(NO)₂}¹⁰ dinitrosyliron complexes (DNICs) [(sparteine)Fe(NO)₂](1) and [(TMEDA)Fe(NO)₂] (2), respectively. The stable and isolable anionic {Fe(NO)₂}⁹ DNIC [(S(CH₂)₃S)Fe(NO)₂]^-(4), with a bidentate alkylthiolate coordinated to a {Fe(NO)₂} motif, was prepared by the reaction of [S(CH₂)₃S]^2-and the cationic {Fe(NO)₂}⁹ [(sparteine)Fe(NO)₂]⁺ (3) obtained from the reaction of complex 1 and [NO][BF₄] inCH₃CN. Transformation from the neutral complex 1 to the anionic complex 4 was verified via the cationic complex3. Here complex 3 acts as an {Fe(NO)₂}-donor reagent in the presence of thiolates. The EPR spectra of complexes3 and 4 exhibit an isotropic signal with g = 2.032 and 2.031 at 298 K, respectively, the characteristic g value of{Fe(NO)₂}⁹ DNICs. On the basis of N-O/Fe-N(O) bond lengths of the single-crystal X-ray structures of the {Fe(NO)₂}⁹/{Fe(NO)₂}¹⁰ DNICs, the oxidation level of the {Fe(NO)₂} core of DNICs can be unambiguously assigned.The mean N-O distances falling in the range of 1.214(6)-1.189(4) Å and the Fe-N(O) bond distances in therange of 1.650(7)-1.638(3) Å are assigned as the neutral {Fe(NO)₂}¹⁰ DNICs. In contrast, the mean N-O bonddistances ranging from 1.178(3) to 1.160(6) Å and the mean Fe-N(O) bond distances ranging from 1.695(3) to1.661(4) Å are assigned as the anionic/neutral/cationic {Fe(NO)₂}⁹ DNICs. In addition, an EPR spectrum incombination with the IR _NO (the relative position of the _NO stretching frequencies and their difference _NO)spectrum may serve as an efficient tool for discrimination of the existence of the anionic/cationic/neutral {Fe(NO)₂}⁹ DNICs and the neutral {Fe(NO)₂}¹⁰ DNICs.