Synthesis, Reactivity, and Electronic Structure of a Bioinspired Heterobimetallic [Ni(渭-S2)Fe] Complex with Disulfur Monoradical character

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• 作者：Robert Rudolph ; Burgert Blom ; Shenglai Yao ; Florian Meier ; Eckhard Bill ; Maurice van Gastel ; Nils Lindenmaier ; Martin Kaupp ; Matthias Driess
• 刊名：Organometallics
• 出版年：2014
• 出版时间：June 23, 2014
• 年：2014
• 卷：33
• 期：12
• 页码：3154-3162
• 全文大小：389K
• ISSN：1520-6041

文摘

The first synthesis of a monoradical Ni(渭-S₂)Fe core in the [(Nacnac)Ni(渭-S₂)Fe(dmpe)₂] complex 3 could be accomplished in good yields by PMe₃ elimination from the zerovalent iron complex [(dmpe)₂(PMe₃)Fe] (2; dmpe =1,2-bis(dimethylphosphine)ethane) upon reaction with the supersulfido nickel(II) complex [(Nacnac)Ni(S₂)] (1; Nacnac = CH{(CMe)(2,6-ⁱPr₂C₆H₃N)}₂). Complex 3 bears Ni(II) and Fe(II) centers, both of which are in a low-spin state. A single electron is located in the HOMO and is somewhat delocalized over the Ni(渭-S₂)Fe core, so that the bridging disulfur subunit exhibits some 鈥渟ubsulfide鈥?S₂^{3鈥?/sup> character. Compound 3 represents a bioinspired example of a monoradical with a Ni(渭-S₂)Fe structural motif, reminiscent of the Ni(渭-S₂)Fe core structure of the active site in [NiFe] hydrogenases. Its oxidation with [Fe(畏5-C₅H₅)₂][B(C₆H₃(CF₃)₂)₄] affords the product [(Nacnac)Ni(渭-S)₂Fe(dmpe)₂][B(C₆H₃(CF₃)₂)₄] (4), and complex 3 can alternatively be prepared via a reductive route upon reaction of [Co(畏5-C₅Me₅)₂][(Nacnac)NiS₂] (6) with the Fe(0) precursor 2. All synthesized complexes were fully characterized, including in some cases single-crystal X-ray diffraction analysis, magnetometry, EPR, NMR, and 57Fe M枚ssbauer spectroscopy. DFT calculations were used to compute the spectroscopic parameters and to establish the electronic structure of 3 and its oxidized and reduced forms and related complexes.}