Magnetostructural characterization of mu(4)-oxohexa-mu(2)-chlorotetrakis(imidazole)copper(II)

The [Cu4OCl6(IMIDH)(4)] complex has been synthesized and its crystal struct ure and magnetic properties determined. The compound crystallizes as a dark green solid in the orthorhombic system, space group P2(1)2(1)2(1), With ce ll constants a = 11.469(2) Angstrom, b = 13.933(2) Angstrom, c = 16.778(3) Angstrom and four formula units per cell. The complex has a tetrameric stru cture of four copper(II) ions connected to a central oxo group, in an appro ximately tetrahedral arrangement. Copper coordination is completed by three mu(2)-chloride ions and an imidazole nitrogen atom, defining a trigonal bi pyramidal environment around each copper ion. A new Heisenberg exchange sch eme has been developed, considering the experimentally observed distortion of the Cu-4 tetrahedron. The magnetic susceptibilities measurements were in terpreted by means of this model, in terms of three coupling constants, J = -7.65 cm(-1) J(s) = 83.3 cm(-1), and J(L) = -58.8 cm(-1), which show a lin ear correlation with the observed Cu-O-Cu angles.