Synthesis, crystal structure, EPR spectra of Cu~(2+) doped [Zn(methylisonicotinate)_2(H_2O)_4]·(sac) 2 single crystal

摘要

The tetraaquabis(methylisonicotinate)zinc(II) disaccharinate [hereafter, [Zn(mein)_2(H_2O)_4]·(sac)_2], complex has been synthesized and characterized by spectroscopic IR, EPR and X-ray diffraction technique. The octahedral Zn(II) ion, which rides on a crystallographic centre of symmetry, is coordinated by two monodentate mein ligands through the ring nitrogen and four aqua ligands to form discrete [Zn(mein)_2(H_2O)_4] unit, which captures two saccharinate ions in up and down positions, each through intermolecular hydrogen bonds. The magnetic environments of Cu~(2+) doped [Zn(mein) _2(H_2O)_4]·(sac)_2 complex have been identified by electron paramagnetic resonance (EPR) technique. EPR spectra of Cu~(2+) doped [Zn(mein)_2(H_2O) _4]·(sac)_2 single crystals have been studied between 113 and 300 K in three mutually perpendicular planes. The calculated results of the Cu~(2+) doped [Zn(mein)_2(H_2O) _4]·(sac)_2 indicate that Cu~(2+) ion contains two different complexes and each complexes are located in different chemical environments and each environment contains two magnetically inequivalent Cu~(2+) sites in distinct orientations occupying substitutional positions in the lattice. The vibrational spectra of this compound were discussed in relation to other compounds containing methyl isonicotinate and saccharinate complexes. The assignments of the observed bands were discussed.