Synthesis, characterisation and reactivity of the molybdenum(VI) dimethyl complex [Mo(NR)2Me2] (R = 2,6-Pri2C6H3)

Abstract

The reaction of [Mo(NR)₂Cl₂(dme)] (R = 2,6-Prⁱ₂C₆H₃, dme = 1,2-dimethoxyethane) with 2 equivalents of methylmagnesium bromide in diethyl ether afforded [Mo(NR)₂Me₂] 2 as a red crystalline solid in good yield. Treatment of 2 with the donor molecules tetrahydrofuran (thf), pyridine, PMe₃, and PMe₂Ph gave the five-co-ordinate adducts [Mo(NR)₂Me₂(L)] (L = PMe₃ 3, PMe₂Ph 4, thf 5 or pyridine 6). Exposure of solutions of 2 to atmospheric dioxygen afforded the orange methoxide-bridged complex [{Mo(NR)₂Me(µ-OMe)}₂] 7. [{Mo(NBu^t)₂Me(µ-OMe)}_n], 8 (n = 1 or 2) was obtained from the reaction of [{Mo(NBu^t)₂Me₂}₂] 1 with dioxygen. The crystal structures of 2, 4 and 7 have been determined.