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 beta-diketiminate ligand L-Me. [(LNiCl)-Ni-Me](2) and (LNiCl2LiTHF2)-Ni-Me, which have tetrahedral geometries in the solid state, are in equilibrium with three-coordinate (LNiCl)-Ni-Me. Thermodynamic parameters for the equilibrium between [(LNiCl)-Ni-Me](2) and (LNiCl)-Ni-Me are DeltaH= 51(5) kJ/mol and DeltaS = 116(11) J/(mol.K). (LNiCl)-Ni-Me forms a tetrahydrofuran complex with a binding constant of 1.2(2) M-1 at 21 degreesC. The chloride complexes were used to generate a three-coordinate nickel(II)-amido complex. This amido complex, (LNiN)-Ni-Me(SiMe3)(2), is compared with (LMN)-M-Me(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 (LMII)-M-Me amido compounds are similar to the trends in three-coordinate (LMII)-M-tBu chloride compounds.