Group IB organometallic Chemistry. XXXV. Crystal and molecular structure of [Cu4{4-MeC6H4)MeC=C(C6H4NMe2-2)}2(C6H4NMe2-2)2], a tetranuclear organo-copper compound containing bridging alkenyl and aryl groups

The crystal and molecular structure of the title compound has been determined by a single crystal X-ray diffraction study using standard Patterson and Fourier methods. The structure was refined by a block-diagonal least-square procedure to a final R value of 0.16 for 3454 reflections. Crystals are monoclinic, space group P2{1}/c, with a 14.007(5), b 12.224(5), c 28.358(8) @9, @b 99.60(1)}o{, and Z @? 4.The molecule consists of a central rhombus-type core of copper atoms to which the alkenyl and aryl groups are bound in a bridging fashion (two electron-three center bonding). The two alkenyl and the two aryl groups each occupy adjoining edges of the Cu{4} core. The dimethylamino groups of the alkenyl ligand coordinate to copper, whereas those of the bridging aryl ligand are free. As a result the copper core is made up of copper atoms which are alternatingly two- and three-coordinate.The structure is discussed in terms of structural information now available for organocopper compounds. The geometry of the Cu{2}C (bridge) moiety in organocopper cluster compounds as expected varies little with the nature of the bridging one-electron organo ligand (alkyl, alkenyl, alkynyl or aryl)