Manganese(II) Trimeric Systems Derived from Pyridyldioximato Ligands: Synthesis, Crystal Structure, and Magnetic Characterization

Three new manganese compounds have been obtained by reaction of the 2,6-diacetylpyridine dioxime (dapdoH(2)) ligand with several Mn-II salts. By using a variety of manganese(II) carboxylates, three Mn-II derivatives with general formula [Mn-3(RCOO)(6)(dapdoH(2))(2)], where RCOO- = formate (1), acetate (2), and benzoate (3), were obtained. Structural analysis reveals chains of trinuclear units for 1 and isolated trinuclear molecules for 2. Compound 1 provides an example of a new topology for the [Mn-3(RCOO)(6)(L)(2)] general formula. Magnetic susceptibility studies reveal topological ferrimagnetism for 1 and conventional antiferromagnetic response for 2 and 3, with coupling constants of -3.1, -3.2, and -1.4 cm(-1) inside the trimeric units of 1, 2, and 3, respectively. ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)