Synthesis,spectroscopic and magnetic properties of methoxo- bridged copper(II) complexes with 2-amino-4-methylpyridine as the ligand

Three new methoxo-bridged copper(II) complexes with 2-amino-4- methylpyridine as the ligand have been synthesized and characterized by elemental analyses, FTIR and electronic spectra, and by their magnetic properties. The complexes exhibit strong antiferromagnetic interactions at room temperature. The u.v.-vis spectra exhibits three absorption bands, which can attributed to d–d, L–M and –* transitions. The i.r. spectra indicates Cu2O2 ring vibrations in the 580–530cm–1 range. The magnetic properties of the [Cu2(2-amino-4-methylpyridine)4(O- Me)2](ClO4)2 complex has been investigated in the 5–270K range and a singlet-triplet energy gap (–2J) of 67cm–1 was observed. All complexes in the solid state are e.p.r.-silent and show no triplet spectrum; in fact a weak signal due to a monomeric impurity are observed. Frozen solution e.p.r. spectra suggest that the complexes dissociate when dissolved in DMF or DMSO.