Synthesis and structural study of (2,2′-bipyridine)perchlorato(styrene)-copper(I)

The reduction of Cu(ClO4)2・6H2O with copper wire in the presence of styrene and 2,2′-bipyridine (bipy) gave the complex [CuI(bipy)(CH2=CHPh)(ClO4)] in methanol. The complex has been characterized by spectroscopic and X-ray diffraction studies. Crystals of the complex are monoclinic, space group P21/n, with a = 12.154(3), b = 14.796(4), c = 10.361(2) A, β = 111.04(2)°, and Z = 4. The geometry about the copper(I) atom is trigonal pyramidal, involving two nitrogen atoms of bipy and two carbon atoms of the olefinic moiety of styrene at equatorial positions in an approximately planar fashion and weak co-ordination to an oxygen atoms of the perchlorate anion at the axial position. The olefinic C=C bond distance of the co-ordinated styrene molecule, 1.358(10) A, is slightly longer than those reported for other free olefin molecules. This slight lengthening is reflected in the 1H n.m.r. spectrum of the olefinic protons and the C=C stretching frequency of the co-ordinated styrene in the Raman spectrum and suggests the importance of dπ(metal)→π*(styrene) back donation in the copper(I)-olefin bonding