SPECTROSCOPIC AND ELECTROCHEMICAL PROPERTIES OF 1,3-DIKETONATOBORON DERIVATIVES

A series of tetracoordinated boron complexes derived from various 1,3- diketones and bidentate ligands (oxalato, malonato, catecholato and di ffuoro) were prepared, Their absorption, fluorescence and phosphoresce nce spectra, at ambient temperature and 77 K, and cyclic voltammmetry in acetonitrile were studied, The boron complexes exhibited high molar absorptivity and fluorescence intensities as compared with the parent diketones; the phenomena are in agreement with the lowest singlet exc ited state possessing the pi, pi, configuration with a rigid chelate structure, The redox potential differences correlate linearly with the lowest singlet (E(S)) as well as the triplet (E(T)) excited state ene rgy with slopes lower than unity, These linear correlations re-state t hat the electron exchange and Coulombic integral also vary proportiona lly to the potential differences, From these correlations, it is possi ble to determine E(S) and E(T) of those boron complexes that do not gi ve fluorescence and phosphorescence.