SYNTHESIS OF A BINUCLEAR COPPER(I) COMPLEX [Cu_2(PPh_3)_6(mu -OOCH)](ClO_4) -INSERTION REACTION OF CARBON DIOXIDE

摘要

A novel binuclear complex [Cu_2(PPh_3)_6(mu-OOCH)](ClO_4) (II) was synthesized via the interaction of carbon dioxide with [Cu(PPh_3)_2(BH_4)] (I) in the presence of PPh_3 and NBu_4(ClO_4). It was characterized by elemental analysis and spectroscopic methods as well as by single-crystal X-ray diffraction. Crystals are monoclinic, space group C_2/c, with a = 25.9l1(5), b= 13.6361(3), c = 26.929(5)A, beta = 90.21(3) deg, V=9323.1(3) A~3, Z = 8 and D_c= 1.314gcm~(-3). The formate ligand of II in the solid state displays a near-perfect linear coordination mode as CO_2 and serves as a bridge for the two Cu(PPh_3)_3 units with the O-C-O bond angle being 180.0(5) deg. A mechanism involving carbon dioxide insertion into the Cu-H bond of [Cu(PPh_3)_2(BH_4)] (I) for the formation of II is proposed.