Investigation into the reaction of (t-BuC5H4)2Nb(η2-Te2)H with CH3Li: Hydride abstraction versus telluride methylation

The reaction of View the MathML source[Cp2′Nb(Te2)H](1) (Cp′ = t -BuC5H4) with CH3Li in THF was examined by variable temperature 1H NMR, ESR and mass spectroscopic means. From these methods it is evident that the diamagnetic compounds View the MathML source[Cp2′NbH2(TeCH3)](2) and View the MathML source[Cp2′Nb(Te)CH3](3) as well as the paramagnetic compound View the MathML source[Cp2′Nb(TeCH3)2](4) form simultaneously. In the subsequent reaction of the intermediate solution with [Co2(CO)8] compound 4 was consumed and the compound View the MathML source[Cp2′Nb(μ-TeCH3)2Co(CO)2] (5) formed in good yield. Complex 5 was characterized by IR and variable temperature 1H NMR spectroscopies. Electrochemical two-electron reduction of 1 leads, in a quasi-reversible process, to products that are not stable in solution.