Synthesis, crystal structure, EPR spectra of doped VO2+ and Cu2+ ions in [Zn(ethylisonicotinate)(2)(H2O)(4)]center dot(sac)(2) single crystal

Abstract

The tetraaquabis(ethylisonicotinate)zinc(II) disaccharinate, [Zn(ein)(2)(H2O)(4)]center dot(sac)(2) (ZENS) (ein: ethyl isonicotinate and sac: saccharinate) complex has been synthesized and its crystal structure has been determined by X-ray diffraction analysis. The magnetic environments of VO2+ and Cu2+ doped Zn(II) complex have been identified by electron paramagnetic resonance (EPR) technique. The title complex crystallizes in monoclinic system with space group P2(1)/c, Z=4. The octahedral Zn(II) ion, rides on a crystallographic centre of symmetry, is coordinated by two monodentate ein ligands through the ring nitrogen and four aqua ligands to form discrete [Zn(ein)(2)(H2O)(4)] unit, which captures two saccharinate ions in up and down positions, each through intermolecular hydrogen bonds. Cu2+ and VO2+ doped ZENS single crystals have been studied at room temperature in three mutually perpendicular planes. The calculated results of the Cu2+ and VO2+ doped in ZENS indicate that Cu2+ and VO2+ ion substitute with the Zn2+ ion in the host lattice. The angular variations of the EPR spectra have shown that two different Cu2+ and VO2+ complexes are located in different chemical environments, and each environment contains two magnetically inequvalent Cu2+ and VO2+ sites in distinct orientations occupying substitutional positions in the lattice and show very high angular dependence. The ground state wave functions of the unpaired electron of Cu2+ ion have been constructed and type of the distortion has, then, been determined. (C) 2008 Elsevier B.V. All rights reserved.