Aminobis(phenolate)s of imidomolybdenum(VI) and -tungsten(VI)

The reactions of trans-[MoO(ONOMe)Cl2] 1 (ONOMe = methylamino-N,N-bis(2-methylene-4,6-dimethylphenolate) dianion) and trans-[MoO(ONOtBu)Cl2] 2 (ONOtBu = methylamino-N,N-bis(2-methylene-4-methyl-6-tert-butylphenolate) dianion) with PhNCO afforded new imido molybdenum complexes trans-[Mo(NPh)(ONOMe)Cl2] 3 and trans-[Mo(NPh)(ONOtBu)Cl2] 4, respectively. As analogous oxotungsten starting materials did not show similar reactivity, corresponding imido tungsten complexes were prepared by the reaction between [W(NPh)Cl4] with aminobis(phenol)s. These reactions yielded cis- and trans-isomers of dichloro complexes [W(NPh)(ONOMe)Cl2] 5 and [W(NPh)(ONOtBu)Cl2] 6, respectively. The molecular structures of 4, cis-6 and trans-6 were verified by X-ray crystallography. Organosubstituted imido tungsten(VI) complex cis-[W(NPh)(ONOtBu)Me2] 7 was prepared by the transmetallation reaction of 6 (either cis or trans isomer) with methyl magnesium iodide.