Relaxation of Excited States in Cr(III) Complexes

摘要

The quantum yields of luminescence and2Elifetimes have been determined as a function of temperature for Cr3plus;in the crystalline hosts, K3Co(CN)6, NaMgAl(C2O4)3middot;9H2O, C(NH2)3Al(SO4)2middot;6H2O(GASH), C(NH2)3Al(SO4)2middot;6D2O(GASD), AlCl3middot;6H2O, and AlCl3middot;6D2O. The effect of structure and environment on the nonradiative transitions has been assessed. For a given complex, the probability of the nonradiative2Erarrw;4A2transition may or may not depend upon environment. In all cases, only phosphorescence is observed at low temperatures, but upon warming, the aquo complexes fluoresce. Depopulation via4T2is the dominant thermal relaxation process of2E.