Magnetostructural Characterization of μ₄-Oxohexa-μ₂-chlorotetrakis(imidazole)copper(II)

Abstract

The [Cu 4 OCl 6 (IMIDH) 4 ] complex has been synthesized and its crystal structure and magnetic properties determined. The compound crystallizes as a dark green solid in the orthorhombic system, space group P 2 1 2 1 2 1, with cell constants a = 11.469(2) Å, b = 13.933(2) Å, c = 16.778(3) Å and four formula units per cell. The complex has a tetrameric structure of four copper(II) ions connected to a central oxo group, in an approximately tetrahedral arrangement. Copper coordination is completed by three μ 2 -chloride ions and an imidazole nitrogen atom, defining a trigonal bipyramidal environment around each copper ion. A new Heisenberg exchange scheme has been developed, considering the experimentally observed distortion of the Cu 4 tetrahedron. The magnetic susceptibilities measurements were interpreted by means of this model, in terms of three coupling constants, J = −7.65 cm - 1, J S = 83.3 cm - 1, and J L = −58.8 cm - 1, which show a linear correlation with the observed Cu−O−Cu angles.