Group 1B organometallic chemistry. Part 25. Crystal and molecular structure of 1,2,3;1,4,5;2,3,6;4,5,6-tetrakis-µ3-2-dimethylaminophenyl-2,5;3,4-bis-µ2-4-tolylethynyl-octahedro-hexacopper(I)

Abstract

The crystal and molecular structure of the title compound has been determined from three-dimensional X-ray diffraction data by Patterson and Fourier methods. Refinement by a block-diagonal least-squares procedure based on 3 643 observed reflections has converged at R 0.044 and R′ 0.057. Crystals are triclinic, space group P, with a= 11.596(2), b= 18.184(3), c= 11.719(2)Å, α= 110.18(1), β= 95.35(1), γ= 91.49(l)°, and Z= 2. The molecule consists of a central, slightly distorted, octahedral arrangement of copper atoms. The dimethylamino-phenyl groups span triangular faces by bridging via carbon a Cu_ap–Cu_eq edge and bonding to a third Cu_eq atom by-nitrogen co-ordination. Two opposite edges of the equatorial Cu₄ plane are symmetrically bridged by 4-tolyl-ethynyl ligands which act as one-electron donors. The bonding is discussed in terms of structural information available for other organocopper compounds. The architecture of the molecule accounts for the exclusive formation of the asymmetric coupling product 2-Me₂NC₆H₄CCC₆H₄Me-4 upon thermolysis of the title compound.