The structural characterization of the first mononuclear alkoxide cation: Isolation and X-ray study of [Mo(OMe)5(CH3CN)]Bi2Cl7

Interaction of molybdenum oxomethoxide and bismuth chloride in toluene/acetonitrile media leads to the formation of an unusual ionic salt [Mo(OMe)5(CH3CN)]Bi2Cl7 (1), providing the first example of an isolated mononuclear alkoxide cation, [Mo(OMe)5(CH3CN)]+ with rather uniform Mo–O(Me) bond lengths. The product can be isolated with moderate yields and only from solutions with considerable excess of the molybdenum reactant (Mo:Bi ≈ 2:1) after refluxing of the reaction mixture, which indicates disproportionation of MoO(OMe)4 in solution into MoO2(OMe)2 and Mo(OMe)6 as a crucial step in its formation.