A magnetostructural study of linear NiIIMnIIINiII, NiIICrIIINiII and triangular NiII3 species containing (pyridine-2-aldoximato)nickel(ii) unit as a building block

Abstract

Three trinuclear complexes, Ni^IIMn^IIINi^II1, Ni^IICr^IIINi^II2 and Ni^II₃3 based on (pyridine-2-aldoximato)nickel(II) units are described. Two of them, 1 and 2, contain metal-centers in linear arrangement, as is revealed by X-ray diffraction. Complex 3 is a homonuclear complex in which the three nickel(II) centers are disposed in a triangular fashion. The compounds were characterized by various physical methods including cyclic voltammetric and variable-temperature (2–290 K) susceptibility measurements. Complexes 1 and 3 display antiferromagnetic exchange coupling of the neighbouring metal centers, while weak ferromagnetic spin exchange between the adjacent Ni^II and Cr^III ions in 2 is observed. The experimental magnetic data were simulated by using appropriate models.