SYNTHESIS AND CHARACTERIZATION OF THE ISOELECTRONIC D10 SPECIES [CU(N(SIMEPH2)2)2]- AND ZN(N(SIMEPH2)2)2

The compounds [Li(THF)4][Cu{N(SiMePh2)2}2] (1) and Zn{N(SiMePh2)2}2 (2) have been synthesized and characterized by X-ray crystallography and IR and H-1 NMR spectroscopy. They were prepared by the reaction of 2 equiv of LiN(SiMePh2)2 with CuBr or ZnCl2 in Et2O or THF solution. The compounds form part of the series M{N(SiMePh2)2}2 (M = Mn (3), Fe (4), Co (5)) which display N-M-N angles in the range 147.0 (1)-170.7 (1)-degrees. In contrast, the N-Cu-N and N-Zn-N moieties have almost perfectly linear angles at the metal of 179.2 (2) and 177.5 (2)-degrees. The average Cu-N and Zn-N distances are near 1.88 and 1.85 angstrom. The major conclusion from the structural data is that the angle at the metal is not necessarily determined by the metal size and that secondary interactions between low-lying unfilled metal orbitals and the electron-rich phenyl group(s) play a key role in determining the overall structure. Crystal data with Mo K-alpha radiation (lambda = 0.710 69 angstrom) at 130 K: 1, a = 17.643 (4) angstrom, b = 14.433 (3) angstrom, c = 26.085 (10) angstrom, beta = 98.79 (2)-degrees, Z = 4, space group P2(1)/c, 6487 (I > 2-sigma(I)) data, R = 0.072; 2, a = 10.917 (5) angstrom, b = 15.485 (8) angstrom, c = 26.963 (14) angstrom, beta = 90.81 (4)-degrees, Z = 4, space group P2(1)/c, 3894 (I > 2-sigma(I)) data, R = 0.055.