Group 6 Imido Complexes Supported by Diamido-Donor Ligands

Reactions of the lithiated diamido-pyridine or diamido-amine ligands Li2N2Npy or Li2N2Nam with [W(NAr)Cl4(THF)] (Ar = Ph or 2,6-C6H3Me2; THF = tetrahydrofuran) afforded the corresponding imido-dichloride complexes [W(NAr)(N2Npy)Cl2] (R = Ph, 1, or 2,6-C6H3Me2, 2) or [W(NAr)(N2Nam)Cl2] (R = Ph, 3, or 2,6-C6H3Me2, 4), respectively, where N2Npy = MeC(2-C5H4N)(CH2NSiMe3)2 and N2Nam = Me3SiN(CH2CH2NSiMe3)2. Subsequent reactions of 1 with MeMgBr or PhMgCl afforded the dimethyl or diphenyl complexes [W(NPh)(N2Npy)R2] (R = Me, 5, or Ph, 6), respectively, which have both been characterized by single crystal X-ray diffraction. Reactions of Li2N2Npy or Li2N2Nam with [Mo(NR)2Cl2(DME)] (R = tBu or Ph; DME = 1,2-dimethoxyethane) afforded the corresponding bis(imido) complexes [Mo(NR)2(N2Npy)] (R = tBu, 7, or Ph, 8) and [Mo(NtBu)2(N2Nam)] (9).