Nickel Complexes of a Bulky β-Diketiminate Ligand

Nickel(II) chloride forms a complex with tetrahydrofuran, NiCl2(THF)1.5, that can be used to prepare nickel chloride complexes of a bulky β-diketiminate ligand LMe. [LMeNiCl]2 and LMeNiCl2LiTHF2, which have tetrahedral geometries in the solid state, are in equilibrium with three-coordinate LMeNiCl. Thermodynamic parameters for the equilibrium between [LMeNiCl]2 and LMeNiCl are ΔH = 51(5) kJ/mol and ΔS = 116(11) J/(mol·K). LMeNiCl forms a tetrahydrofuran complex with a binding constant of 1.2(2) M-1 at 21 °C. The chloride complexes were used to generate a three-coordinate nickel(II)−amido complex. This amido complex, LMeNiN(SiMe3)2, is compared with LMeMN(SiMe3)2 (M = Mn, Fe, Co) (Panda, A.; Stender, M.; Wright, R. J.; Olmstead, M. M.; Klavins, P.; Power, P. P. Inorg. Chem. 2002, 41, 3909−3916). Trends in the metrical parameters of the three-coordinate LMeMII amido compounds are similar to the trends in three-coordinate LtBuMII chloride compounds (Holland, P. L.; Cundari, T. R.; Perez, L. L.; Eckert, N. A.; Lachicotte, R. J. J. Am. Chem. Soc. 2002, 124, 14416−14424).