Syntheses of Tungsten tert-Butylimido and Adamantylimido Alkylidene Complexes Employing Pyridinium Chloride As the Acid

Routes to new tungsten alkylidene complexes that contain tert-butylimido or adamantylimido ligands have been devised that begin with a reaction between WCl6 and 4 equivalents of HNR(TMS) to give [W(NR)2Cl(μ-Cl)(RNH2)]2 (R = t-Bu or 1-adamantyl). Alkylation leads to W(NR)2(CH2R′)2 (R′ = t-Bu or CMe2Ph), which upon treatment with pyridinium chloride yields W(NR)(CHR′)Cl2(py)2 complexes, from which W(NR)(CHR′)(pyrrolide)2 and two W(N-t-Bu)(CHR′)(pyrrolide)(OAr) complexes (OAr = hexamethyl- or hexaisopropylterphenoxide) have been prepared.