Synthesis, crystal structure and magnetic properties of (acetato-kappa O-2,O ‘)bis(5,5 ‘-dimethyl-2,2 ‘-bipyridine-kappa N-2,N ‘)nickel(II) perchlorate monohydrate.

Synthesis, crystal structure and magnetic properties of (acetato-kappa O-2,O ‘)bis(5,5 ‘-dimethyl-2,2 ‘-bipyridine-kappa N-2,N ‘)nickel(II) perchlorate monohydrate.

The title hydrated ionic complex, [Ni(CH3COO)(C12H12N2)(2)]ClO4 center dot H2O or [Ni(ac)(5,5′-dmbpy)(2)]ClO4 center dot H2O (where 5,5′-dmbpy is 5,5′-dimethyl-2,2′-bipyridine and ac is acetate), (1), was isolated as violet crystals from the aqueous ethanolic nickel acetate-5,5′-dmbpy-KClO4 system. Within the complex cation, the Ni-II atom is hexacoordinated by two chelating 5,5′-dmbpy ligands and one chelating ac ligand. The mean Ni-N and Ni-O bond lengths are 2.0628 (17) and 2.1341 (15) angstrom, respectively. The water solvent molecule is disordered over two partially occupied positions and links two complex cations and two perchlorate anions into hydrogen-bonded centrosymmetric dimers, which are further connected by pi-pi interactions. The magnetic properties of (1) at low temperatures are governed by the action of single-ion anisotropy, D, which arises from the reduced local symmetry of the cis-NiO2N4 chromophore. The fitting of the variable-temperature magnetic data (2-300 K) gives g(iso) = 2.134 and D/hc = 3.13 cm(-1).