Synthesis of Nickel-Thiolate Complexes: Relevance to the Nickel Site of [NiFe] Hydrogenases

• Main Authors: Hsin-Hung Chen, 陳信宏
• Other Authors: Wen-Feng Liaw
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/64487007431885604774

碩士 === 國立清華大學 === 化學系 === 95 === The neutral mixed-valence [Ni(II)Ni(III)] complex [Ni2(P(o-C6H3-3-SiMe3-2-S)3)(P(o-C6H3-3-SiMe3-2-S)2(o-C6H3-3-SiMe3-2-SCH3))] (1) and the dianionic dinuclear [Ni(II)Ni(II)]2- complex [K-18-crown-6-ether]2[Ni2(P(o-C6H3-3-SiMe3-2-S)3)2] (2) were prepared from reaction of [K-18-crown-6-ether][Ni2(P(o-C6H3-3-SiMe3-2-S)3)2] with [Me3O][BF4] and KC8 in same equivalent, individually. The anionic mixed-valence [Ni(II)Ni(III)]- complex [PPN][Ni2(P(o-C6H3-3-SiMe3-2-S)3)2] (3) was synthesized by reaction of complex 1 and [PPN][BH4]. The electronic perturbation from the sulfur methylation of [K-18-crown-6-ether][Ni2(P(o-C6H3-3-SiMe3-2-S)3)2] triggers the stronger Ni…Ni interaction and the geometrical rearrangement from the diamond shape of [NiS2Ni] core with Ni…Ni distances of 2.8289(15) Å to the butterfly structure of [Ni(��-S)2Ni] to yield complex 1 with Ni…Ni distances of 2.6088(1) Å to reimburse the deficiency of electron density surrounding [Ni(II)Ni(III)] centers. The distinctly different Ni…Ni distance (2.6088(1) Å for 1, 3.1855(12) Å for 2, and 2.8712(12) Å for 3) indicates a balance of geometry requirement for different coordination environment of Ni-thioether and Ni-thiolate in complex 1, 2, and 3. The anionic complex [PPN][Ni(SnBun)(P(o-C6H3-3-SiMe3-2-S)3)] (5) was synthesized by reaction of [PPN][NiIII(SEt)(P(o-C6H3-3-SiMe3-2-S)3)] and n-Bu3SnH in THF solution. All of these complexes are isolated and characterized by UV-vis, single crystal X-ray diffraction, EPR, and elemental analysis.