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- Molybdenum complexes bearing the tris(1-pyrazolyl)methanesulfonate ligand: synthesis, characterization and electrochemical behaviourPublication . Dinoi, Chiara; Guedes Da Silva, M. FĂĄtima C.; Alegria, Elisabete; Smolenski, Piotr; Martins, Luisa; Poli, Rinaldo; Pombeiro, ArmandoThe tris(1âpyrazolyl)methanesulfonate lithium salt Li(Tpms) [Tpms = SO3C(pz)3â] reacts with [Mo(CO)6] in NCMe heated at reflux to yield Li[Mo(Tpms)(CO)3] (1 ), which, upon crystallization from thf, forms the coordination polymer [Mo(Tpms)(CO)2(ÎŒâCO)Li(thf)2]n (2 ). Reaction of 1 with I2, HBF4 or AgBF4 yields [Mo(Tpms)I(CO)3] (3 ), [Mo(Tpms)H(CO)3] (5 ) or [Mo(Tpms)O2]2(ÎŒâO) (7 ), respectively. The highâoxidationâstate dinuclear complexes [{Mo(Tpms)O(ÎŒâO)}2] (4 ) and [{Mo(tpms)OCl}2](ÎŒâO) (6 ) are formed upon exposure to air of solutions of 3 and 5 , respectively. Compounds 1 â7 , which appear to be the first tris(pyrazolyl)methanesulfonate complexes of molybdenum to be reported, were characterized by IR, 1H and 13C NMR spectroscopy, ESIâMS, elemental analysis, cyclic voltammetry and, in the cases of Li(Tpms) and compounds 2 , 4· 2CH3CN, 6· 6CHCl3 and 7 , by Xâray diffraction analyses. Li(Tpms) forms a 1D polymeric structure {i.e., [Li(tpms)]n } with Tpms as a tetradentate N2O2 chelating ligand that bridges two Li cations with distorted tetrahedral coordination. Compound 2 is a 1D coordination polymer in which Tpms acts as a bridging tetradentate N3O ligand and each Li(thf)2+ moiety is coordinated by one bridging CO ligand and by the sulfonyl group of a contiguous monomeric unit. In 4 , 6 and 7 , the Tpms ligand is a tridentate chelator either in the NNO (in 4 ) or in the NNN (in 6 and 7 ) fashion. Complexes 1 , 3 and 5 exhibit, by cyclic voltammetry, a singleâelectron oxidation at oxidation potential values that indicate that the Tpms ligand has an electronâdonor character weaker than that of cyclopentadienyl.