TRI-MERIC AND TETRA-MERIC COPPER(I) AMIDES (CU[N(SIMEPH2)2])3 AND (CU[N(SIME2PH)2]4

The compounds {Cu[N(SiMePh2)2]}3 1 and {Cu[N(SiMe2Ph)2]}4 2 have been synthesised by the reaction of CuBr with the appropriate lithium silylamide in diethyl ether solution. Both were characterized by X-ray crystallography, H-1 NMR and IR spectroscopy, and elemental analysis. They represent the first copper silylamides to be completely characterized by X-ray crystallography. Compound 1 has a very rare trimeric structure with the metals disposed in a triangular fashion and bridged by amide ligands. The less-crowded derivative 2 has an amide-bridged tetrameric structure and an almost square-planar arrangement of four coppers. The bridging amides are displaced from the Cu4 plane such that the Cu4N4 core possesses a butterfly structure. In 1 the Cu ... Cu and Cu-N distances average 2.481(8) and 1.976(8) angstrom and the corresponding distances in 2 are 2.69(3) and 1.936(6) angstrom. Crystal data: 1, orthorhombic, space group Pbca, a = 29.421(8), b = 18.630(4), c = 29.971(8) angstrom, Z = 8, R = 0.069 for 4239 [I > 3-sigma(I)] data; 2, triclinic, space group P1BAR, a = 15.365(3), b = 15.420(3), c = 17.797(3), angstrom, alpha = 67.58(1), beta = 64.28(1), gamma = 66.95(1)-degrees, Z = 2, R = 0.050 for 10 999 [I > 2-sigma(I)] data.