NATURE OF TRANSIENTS IN THE LASER FLASH-PHOTOLYSIS OF THE TRIBROMOCUPRATE(I) COMPLEX

Laser flash excitation of the CTTS band of CuBr32- at 266 nm results i n the formation of a luminescent species which decays through a couple d mechanism consistent with the formation of an emitting triplet trico ordinated exciplex in equilibrium with a nonemitting triplet dicoordin ated species. The rate constants for some of the decay processes, as w ell as the formation constant of the radiative intermediate, are estim ated. Hydrated electrons and Cu(II) ions are also efficiently produced in about-a 1:1 molar ratio in a competing pathway with the copper(I) exciplex formation. Time-resolved absorbance spectra of the hydrated e lectron and the luminescent species were obtained, leading to the conc lusion that the exciplex forms in high yield at high ligand concentrat ions. Another intermediate appears to be the Br-2(-) radical anion.