Structure and zero-field splitting bis(1,2-dimethylimidazole) bis(acetato)nickel(II) molecular complex

A new neutral mononuclear nickel(II) complex of the composition [Ni(Me(2)iz )(2)(ac)(2)] was prepared and characterised (Me(2)iz = 1,2-dimethylimidazol e, ac = acetate). The X-ray structure analysis shows that the carboxylato g roup coordinates as a bidentate ligand with a low O-Ni-O angle of 62 degree s. Therefore an enhanced magnetic anisotropy is expected and confirmed by t he magnetic susceptibility measurements. The set of magnetic parameters is g(x), g(y), = 2.175, g(z) = 2.263, D/hc = -14.30 cm(-1), and chi (TIP) = 2. 04 x 10(-9) m(3) mol(-1). The axial zero-field splitting parameter D spans the interval of large values owing to a combined effect of the ligand field and angular momentum anisotropy. (C) 2001 Elsevier Science B.V. All rights reserved.