Magnetostructural Characterization of μ 4 -Oxohexa-μ 2 -chlorotetrakis(imidazole)copper(II)

The [Cu4OCl6(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 P212121, with cell constants a = 11.469(2) A, b = 13.933(2) A, c = 16.778(3) A 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 μ2-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 Cu4 tetrahedron. The magnetic susceptibilities measurements were interpreted by means of this model, in terms of three coupling constants, J = −7.65 cm-1, JS = 83.3 cm-1, and JL = −58.8 cm-1, which show a linear correlation with the observed Cu−O−Cu angles.