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Abstract
Compounds of formulae [M(Hbg)2] [Cu(acac)2 X]2 (1) and [Ni(Rbg)2] [Cu(acac)2 Cl2] (2) (acac = acetylacetonate, X = Cl, Br, I; M = Cu, Ni; Hbg = biguanide, Rbg = N-alkylbiguanide, R = CH3 C2 H5) have been prepared by the interaction of the respective chelates in methanol. The presence of five and six coordinate copper(II) in the anions of (1) and (2) respectively is suggested from their conductance data, electronic and vibrational spectra, magnetic moments and thermal analyses. Compound (1), where M = Cu and X = Cl has been characterized by single crystal X-ray crystallography. Crystals are orthorhombic, space group Pbca with Z = 4 with a = 15.218(2), b = 15.986(3), c = 14.565(3)Å. The structure was solved by Patterson and Fourier methods and refined by least-squares methods to R = 0.052 and RW = 0.052 for 4267 reflexions and R = 0.065 for all 5206 reflexions. The structure consists of square-planar [Cu(Hbg)2]2+ cations and square-pyramidal [Cu(acac)2 Cl]− anions. The nonhydrogen atoms of the cation lie within 0.02Å of the plane of best fit defined by the two chelate rings. The copper atom in the anion lies 0.2Å above the plane of best fit of four oxygen atoms of the coordinated acetylacetonate and is directed towards the chlorine atom. The ions are linked by very weak hydrogen bonds between the oxygen atoms of the anion and the -NH groups of the cation. The Cu-Cl distance is much longer than those in CuCl2.