Bis chelate Cu(II) complexes of dafone - Synthesis, structural, EPR and optical spectral studies

Abstract

Three examples of Cu(II) complexes with dafone, Cu(dafone)2Br2 (1), [Cu(dafone)2(H2O)2](NO3)2 (2) and [Cu(dafone)2(H2O)2](ClO4) 2 (3) have been synthesized and characterized structurally and spectroscopically. All complexes show unsymmetric chelation of dafone with one Cu - N bond being much longer than the other. Powder diffuse reflectance spectra have been recorded for 1, 2 and the known complex, Cu(dafone)2Cl2 (4) and correlated with the molecular g-values for this relatively new type of Cu(II) chromophore. Compounds 1 and 2 were found to be sensitive to grinding leading to additional EPR signals for 1 and changes in the X-ray powder diffraction patterns.