CRYSTAL AND MOLECULAR-STRUCTURE, AND ELECTRONIC-PROPERTIES OF HEXAKIS(IMIDAZOLE)COPPER(II) FORMATE

The crystal and molecular structure of [Cu(Im)(6)] (HCOO)(2) (Im = imi dazole) has been determined by X-ray diffraction methods. The compound is built of centrosymmetric Cu(Im)(6)(2+) cations and non-coordinated HCO, anions, linked through H-bonds giving a layered structure in the ac plane. The coordination polyhedron around the Cu atoms can be desc ribed as a rhombically-distorted octahedron (CuN2N2'N-2 '' chromophore s). Both electronic and e.p.r. spectra are indicative of an essentiall y d(x2-y2) ground state for the Cu-II ions. No exchange coupling has b een detected down to 4.2 K by means of magnetic susceptibility measure ments. This feature is discussed on the basis of the structural data.