Synthesis, Spectroscopy and Magnetism of Alkoxo?bridged Dinuclear Copper(II) Complexes with 2 ? Amino ? Picolines as the Ligands

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The synthesis, spectroscopic and magnetic characterization of a series of new alkoxo-bridged binuclear copper (II) compounds are described. All complexes have the general formula [Cu (m-OR)(L)2]2(ClO4)2 · x H2O, in which m-OR = CH3O-, C2H5O- or C3H7O-, L = 2-amino-4-methylpyridine (abbreviated A4PIC) and 2-amino-5-methylpyridine ( abbreviated A5PIC). The title compounds all consist of dinuclear units with alkoxo-bridging group. All complexes have been synthesized in one-step reaction, and characterized by elemental analysis, FTIR and electronic spectra and by magnetic properties. The compounds exhibit strong antiferromagnetic interaction at room temperature. The UV-Vis spectra shows three absorption bands, which can be attributed to d-d transition of copper (II) ion, ligand®metal charge transiton and p®p* transition of the ligand. The IR spectra indicates Cu2O2 ring vibrations in 500 -570 cm-1 range. The magnetic properties of the [Cu2(A5PIC)4)(O-CH3)2](ClO4)2 complex has been investigated in the 5-265 K range and a singlet-triplet energy gap (-2J) of 126 cm-1 was observed.