Coordination complexes of bifunctional compounds - I. Synthesis and properties of bis[5-(2-oxyphenyl)-3-phenyl-1,2,4-oxadiazolyl]copper(II). A fluorescent coordination compound of Cu(II)

The synthesis of two Cu(II) bis complexes of a substituted 1,2,4-oxadiazoie, which acts as part of a bidentate ligand, is reported for the first time. The two coordination compounds, which form an inseparable mixture, are characterized mainly via vibrational and EPR spectroscopy. Room temperature fluorescence is observed from two uncoupled excited states of the complexes, and the respective lifetimes are approximately 600 ps and 5 ns. The fluorescence quantum yields are a function of excitation wavelength, varying between 1.7 and 9.0 x 10(-3). These values are slightly higher than those of the isolated ligand. (C) 1999 Elsevier Science S.A. All rights reserved.