Syntheses, structures, and magnetic properties of dinuclear/1-D copper(II) acetato and formato derivatives with methylpyrazine and dimethylpyrazine

In this study, {[Cu2(mu-HCO2)4](mu-Mepyrz)}n (1), [Cu2(mu-HCO2)4(Mepyrz)2] (2), {[Cu2(mu-AcO)4](mu-Mepyrz)}n (3), [Cu2(mu-AcO)4(Mepyrz)2] (4), [Cu2(mu-AcO)4(2,3-Me2pyrz)2] (5), [Cu2(mu-AcO)4(2,6-Me2pyrz)2] (6), and {[Cu2(mu-AcO)4](mu-2,5-Me2pyrz)}n (7) have been synthesized and characterized by chemical analysis and electronic spectroscopy. Compounds 2, 4, 5, and 6, characterized by single-crystal X-ray diffraction, are composed of molecular dimers based on a paddle-wheel motif with two coppers, four syn-syn carboxylates, and two ligands coordinated to copper in the axial positions. In 7, chains of [Cu2(mu-AcO)4] dimers with 2,5-Me2pyrz as bridging ligands are formed. Magnetic properties and electron paramagnetic resonance results of the compounds are also described.