Synthesis, spectral, magnetic and electrochemical properties of new dimeric copper(II) complexes

Four new ligands, bis-[3,5-disubstituted-2-hydroxybenzyl]-N-alkylamines (L-1-L-4) with three potential donor sites, capable of forming dimeric copper(II) complexes have been prepared. The dimeric nature of the complexes has been confirmed by FAB mass spectral studies. Molar conductance studies indicate that the complexes are neutral. Electrochemical studies indicate that the complexes undergo quasi reversible two step single electron transfers at negative potentials (E-pc(1)=-0.34 to -0.48 V, E-pc(2)=-0.59 to -0.72 V). Variable temperature magnetic studies indicate that the complexes are antiferromagnetically coupled (-2J=290 to 400 cm(-1)). ESR spectral studies in DMF indicate that the complexes are dimeric and undergo dissociation on addition of pyridine. (C) 1999 Elsevier Science Ltd. All rights reserved.