摘要 : New mono-dithiolene molybdenum (IV) complexes of cis-1, 2-dicyano-1, 2-ethylenedithiolato [(mnt)~(2-)] have been synthesized as models for molybdenum enzymes, with 4,4'-di-tertbutyl-2,2'-bipyridine (Bu_2bpy) and, N,N'-tetraethylet... 展开 New mono-dithiolene molybdenum (IV) complexes of cis-1, 2-dicyano-1, 2-ethylenedithiolato [(mnt)~(2-)] have been synthesized as models for molybdenum enzymes, with 4,4'-di-tertbutyl-2,2'-bipyridine (Bu_2bpy) and, N,N'-tetraethylethyl-enediamine (Et_4en) as ancillary ligands, and characterized by IR, UV/Vis, elemental analysis, ESI-mass and electrochemical techniques. The temperature-dependent ~1H NMR spectra, recorded in CD_3CN solution, indicated that [MoO(mnt)(Bu_2bpy)] (1) has a rigid structure but [MoO(mnt)(Et_4en)] (2) showed dynamic conformational inversion processes involving the chelating ethylenediamine unit. The complexes exhibited different reactivities toward molecular oxygen: 1 gave a single oxo-bridged dimolybdenum dimer complex [Mo_2O_3(mnt)_2(Bu_2bpy)_2] (3), while 2 did not react with O_2 and kept its mononuclear structure. Both complexes have almost the same redox potential for Mo~(IV/V), and so the steric bulkiness and conformational dynamics were thought to cause this marked contrast. The obtained dimolybdenum complex 3 was also structurally characterized and investigated, and found to be a new dimolybdenum complex with one dithiolene per molybdenum. The crystal structure of the starting complex 4 was also reported. 收起