Synthesis, structure, spectral and magnetic properties of a dinuclear copper(II)/nickel(II) complex bridged by glyoximate groups

A new dinuclear complex of formula [(tmen)(H2O)(2)Ni(Hdmg)(dmg)Cu]. ClO4 (H (2)dmg=dimethylglyoxime, tmen= tetramethylenediamine) has been synthesized. The crystal structure of the complex has been solved by a single-crystal X -ray diffraction method. The structure consists of one cationic dinuclear c omplex, [(tmen)(H2O)(2)Ni(Hdmg)(dmg)Cu](+), and one anion, ClO4-. In the di nuclear cationic complex the copper(II) ion and the nickel(II) ion are brid ged by two oximate groups, one through the nitrogen and oxygen atoms and th e other only through the oxygen atom. The intramolecular Cu ... Ni distance is 3.424 Angstrom. The geometry around the copper atom is a distorted squa re pyramid, and the geometry around the nickel atom is a distorted octahedr on. Variable-temperature magnetic susceptibility measurements (75-300 K) on the title complex revealed the occurrence of an intramolecular antiferroma gnetic interaction through the oximate bridges. The IR and UV-Vis spectra h ave also been investigated. (C) 1999 Elsevier Science Ltd. All rights reser ved.