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-methylpyridin e as the ligand have been synthesized and characterized by elemental analys es, FTIR and electronic spectra, and by their magnetic properties. The comp lexes exhibit strong antiferromagnetic interactions at room temperature. Th e u.v.-vis spectra exhibits three absorption bands, which can attributed to d-d. L-M and pi-pi* transitions. The i.r. spectra indicates Cu2O2 ring vib rations in the 580-530 cm(-1) range. The magnetic propel ties of the [Cu-2( 2-amino-4-methylpyridine)(4)(O-Me)(2)](ClO4)(2) complex has been investigat ed in the 5-270 K range and a singlet-triplet energy gap (-2J) of 67 cm(-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 dissoci ate when dissolved in DMF or DMSO.