Magnetostructural correlations in heteroleptic nickel(II) complexes

Abstract

Heteroleptic nickel(II) complexes with the general formula Ni(L) m (H 2O) n (X) k , have been synthesized and structurally characterized; L stands for neutral N-donor ligands: 4-benzofuropyridine ( bzfupy), dimethylfuropyridine ( Me 2 fupy) and 1,2-dimethylimidazole ( Me 2 iz), X = acetate or Cl −. The structures of the complexes [Ni( bzfupy) 2( ac) 2(H 2O) 2], [Ni( Me 2 fupy) 2(H 2O) 4]( ac) 2 and [Ni( Me 2 iz) 4(H 2O) 2]Cl 2 · 3H 2O are formed from {NiO 2O′ 2N 2}, {NiO 4N 2} and {NiN 4O 2} chromophores, respectively. These complexes and two other previously characterized complexes, [Ni( pz) 4( ac) 2], pz – pyrazole, and [Ni(L NN) 2(H 2O) 2], L NN – bidentate chelating ligand, were subjected to magnetochemical investigation down to 2 K (susceptibility and magnetization measurements). They show magnetic behaviour typical for zero-field splitting systems. The axial parameter of the zero-field splitting, D, adopts either positive or negative values and correlates with the axial distortion of the coordination polyhedra.