PHOTOCHEMISTRY OF METALLOPORPHYRINS IN POLYMER MATRICES. LASER PHOTOLYSIS STUDIES OF CHLOROCHROMIUM(III) TETRAPHENYLPORPHYRIN IN POLYSTYRENE FILMS IN THE TEMPERATURE RANGE 77-300 K

Nanosecond laser photolysis studies of chloropyridinato- and chloroaquachromium(III) tetraphenylporphyrin, ClCrIIITPP(Py) and ClCrIIITPP(H2O), dissolved in polystyrene films have been carried out in the temperature range 77−300 K. The transient observed for ClCrIIITPP(Py) after laser pulsing is solely the excited states (the tripquartet, 4T1, and tripsextet, 6T1, states). The emission from the tripquartet state, 4T1, is detected upon laser excitation of ClCrIIITPP(Py). No photodissociation of axial pyridine is detected in the temperature range studied. The laser photolysis of ClCrIIITPP(H2O) in polystyrene films gives two transients; the excited states (4T1 and 6T1) of ClCrIIITPP(H2O) and the five coordinate ClCrIIITPP yielded by the photodissociation of axial H2O from ClCrIIITPP(H2O). The yields of the excited states (4T1 and 6T1 ) for both ClCrIIITPP(Py) and ClCrIIITPP(H2O) were found to increase with a decrease in temperature. The lifetimes and the relative yields of the excited states and the relative...