Preparation and Activation of Complexes of the Type [((mesityl)NCH₂CH₂)₂NX]ZrMe₂ (X = H, Me) with [Ph₃C][B(C₆F₅)₄] or [PhNMe₂H][B(C₆F₅)₄]

The zirconium dimethyl complexes [N2NX]ZrMe2 (N2NX = [(MesNCH2CH2)2NX]; Mes = mesityl; X = H (1a), Me (1b)), have “mer” structures in the solid state in which the amido nitrogens occupy “axial” positions in a trigonal bipyramid. The reaction of 1b with 1 equiv of [Ph3C][B(C6F5)4] followed by addition of diethyl ether yielded the ether adduct {[N2NMe]ZrMe(Et2O)}+ (with [B(C6F5)4]- as the anion), an X-ray study of which revealed it to be a fac trigonal-bipyramidal species in which the diethyl ether is coordinated in an apical position. The reaction of 1b with 1 equiv of [PhNMe2H][B(C6F5)4] led to {[N2NMe]ZrMe(NMe2Ph)}[B(C6F5)4], solution NMR studies of which suggest a structure analogous to that of {[N2NMe]ZrMe(Et2O)}+. Heating solutions of {[N2NMe]ZrMe(NMe2Ph)}[B(C6F5)4] led to C−H activation in one mesityl o-methyl group and formation of methane. The reaction of 1b with 0.5 equiv of [Ph3C][B(C6F5)4] yielded [{[N2NMe]ZrMe}2(μ-Me)][B(C6F5)4] (5b), an X-ray diffraction study of which revealed an almost linea...