Synthesis and structure of copper(II) trans-diaqua-bis(3-hydroxybenzoylhydrazine) nitrate dihydrate [Cu(C7H8O2N2)2(OH2)2](NO3)22H2O

Abstract

Synthesis of [Cu(m-HBH)2(OH2)2](NO3)2·2H2O, where m-HBH = C7H8O2N2 (3-hydroxybenzoylhydrazine), is described. The structure of the compound was studied by X-ray phase analysis and IR spectroscopy; crystal data are a = 57.415(6) A, b = 19.760(2) A, c = 7.586(2) A; Fdd 2, Z = 16, R(F) = 0.053. The compound consists of [Cu(m-HBH)2(OH2)2]2+ complex cations, NO3− anions, and two water molecules. The similarity between the IR spectra of Cu(m-HBH)2(NO3)2·nH2O and Co(m-HBH)2(NO3)2·5H2O, element analysis data, and crystal data obtained at the first stage of X-ray analysis show that the structures and compositions of these compounds are identical relative to the type of surroundings of the central atom. In contrast to the cobalt compound [Co(m-HBH)2(OH2)2](NO3)2·3H2O, in which the cobalt atom has a nearly regular octahedron as a coordination polyhedron, the copper(II) compound has a square bipyramid around the copper atom; c.n. is 6 = 4 + 2 (planar distances: 2.013(2) A, 2.021(2) A, 2.033(3) A, 2.087(3) A; axial distances: 2.367(3) A, 2.374(3) A) and lacks one crystallization water molecule.