synthesis, spectroscopy and magnetism of alkoxobridged dinuclear copper(ii) complexes with 2  amino  picolines as the ligands

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.