Eightfold Electrophilic Methylation of Octacyanotungstate [W(CN)]: Preparation of Homoleptic, Eight-Coordinate Methyl Isocyanide Complexes [W(CNMe)]

Homoleptic eightfold coordinated methyl isocyanide complexes of W(IV) and W(V) have been prepared for the first time. The reaction of [NBu][W(CN)] with methyl triflate (MeOTf) gives [W(CNMe)][OTf]. The even stronger methylating mixture of methyl fluoride (MeF) and arsenic pentafluoride (AsF) in liquid sulfur dioxide (SO) is able to fully alkylate both [NBu][W(CN)] and [NBu][W(CN)]. The paramagnetic octakis(methyl isocyanide)tungsten(V) complex [W(CNMe)][AsF] is thermally highly unstable above -30 °C. All compounds have been characterized via single-crystal X-ray diffraction and IR, Raman, and NMR or EPR spectroscopy.