The equilibrium constant for the stepwise formation of Cu(NH3)3+was determined at 1 M ionic strength, with a value of 0.050, and its ultraviolet spectrum was resolved in the 210-340-nm region. Gaussian resolution of the absorption spectrum gave weak bands at 295 and 270 nm, assumed to be CTTS bands, and a stronger band at 229 nm. Laser flash experiments at 266 and 308 nm yielded transients in solutions containing no electron scavengers with absorption spectra resembling that of the hydrated electron. Continuous-photolysis studies using ammonium ions as electron scavengers resulted in geminate-pair scavenging kinetics, which indicate that the ammonium ion is a much better scavenger than previously reported. The results of the dependence of quantum yield on temperature are consistent with a geminate pair consisting of oppositely charged species. The diamminecopperspecies appears not to be photoactive in the 240-320-nm region. The action spectrum of the triammine complex conforms to the CTTS assignment of the 295- and 270-nm bands.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Inorganic Chemistry