Synthesis and x-ray crystal structure of [Li(C4H8O)(4)][Ni(2,4,6-Me(3)C(6)H(2))(3)]

The tetrahydrofuran-solvated lithium salt of the ato anion [Ni(mes)(3)](-) (mes = mesityl, 2,4,6-Me(3)C(6)H(2)) was obtained as a crystalline solid from the interaction of NiCl2(dme), (dme = 2,2'-dimethoxyethane) and mesityl lithium in Et(2)O-C4H8O. The blue compound 1 is unstable above ca - 10 degrees C and the X-ray crystal structure was determined at low temperature. The metal centre was found to exhibit an unusual T-shaped coordination geometry, which can be explained in terms of CH3 ... Ni agostic interactions at the fourth site of a formally square-planar Ni-II centre. Reactions of 1 with donor ligands produced Ni(2,6-Me(2)C(6)H(3)NC)(4), Ni(Ph(2)PCH(2)CH(2)PPh(2))(2) and Ni(mes)(2) (Me(2)NCH(2)CH(2)NMe(2)). Crown copyright (C) 1996 Published by Elsevier Science Ltd