SOLUTION PHOSPHORESCENCE OF TRANS-CYANOACIDOTETRAAMMINE-CHROMIUM(III)COMPLEXES - COMPARISON WITH MODELS FOR DOUBLET-STATE DEACTIVATION

The trans-Cr(NH3)4X(CN)z+ ions, where X denotes CN-, NH3, NCS-, H2O, F - and Cl-, exhibit fairly intense and long-lived emissions compared wi th those of analogous species not containing cyanide ligands. The phos phorescence decay rates in acidic aqueous solution around room tempera ture, and their activation parameters, are examined for the whole seri es. The lifetime values at 20-degrees-C vary between 40 and 0.26 mus, and obey Adamson's empirical emission rules. The activation energies a re in the 25-55 kJ mol-1 range. The data are discussed in terms of the possible processes controlling the doublet-state lifetime under ambie nt conditions.