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A new crystalline polymorphic phase of tetrakis(mu2-benzoato-O,O')-bis(dimethyl sulfoxide)dicopper(II) was obtained by direct synthesis, in space group P2(1)/n. The copper coordination is in a slightly distorted square pyramidal geometry with an intramolecular Cu...Cu distance of 2.6494(8) angstroms. The Cu-O distances of the two copper in a dimer are different, giving different chemical environments for each Cu ion. The crystal structure is built up of well-separated stacking columns oriented along the b-axis, with units uniformly spaced, producing a one-dimensional (1-D) zigzag chain through Cu(II)-S...S-Cu(II) interdimer interactions [S...S separation: 3.975(2) angstroms]. Magnetization measurements in the range 2-300 K indicate two magnetic orderings, at low temperature (T < 10 K) a weak ferromagnetic ordering is observed, and above this temperature an antiferromagnetic behavior takes place. ESR spectra at 300 and 77 K of a polycrystalline sample show the characteristic signal of zero-field with D = 0.354 cm(-1), consistent with a ferromagnetic Cu...Cu exchange interaction at low temperature.

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The title compound, [ZnBr(2)(C(15)H(26)N(2))], when synthesized starting from Zn(0), is obtained in two polymorphic forms, one belonging to space group P2(1)2(1)2(1) and one to P1. The present contribution deals with the triclinic phase, which is isostructural with the orthorhombic form but presents a larger metal-metal intermolecular separation; the Zn.Zn distance is 7.4715 (6) A for the triclinic polymorph as opposed to 6.534 A for the orthorhombic polymorph.