Synthesis and characterization of a binuclear coumarin-3-carboxylate copper(II) complex

The copper(II) complex of coumarin-3-carboxylic acid (CcaH) has been prepar ed and characterized on the basis of elemental and thermal analysis, IR, Ra man, EPR, UV-Vis reflectance and H-1-NMR spectra. A detail analysis of all spectra data is presented with particular emphasis on the elucidation of th e coordination mode of the ligand and the structure of the complex. All dat a are consistent with a binuclear structure for the complex with four couma rin-3-carboxylates as bridges and one water ligand per copper ion. The sign ificantly lower than the spin-only value magnetic moment of the complex and the EPR spectra at various temperature are indicative of a magnetic intera ction between the two copper atoms. (C) 2001 Elsevier Science B.V. All righ ts reserved.