Viscosity-dependent dual phosphorescence of phenyl alkyl ketones

摘要: Abstract Several phenyl alkyl ketones display two overlapping short-lived phosphorescences at 77°K, with 0—0 bands 384 nm (74.5 kcal) and 397 (72.0 kcal). The higher energy emission (τ = 5–10 msec) is favored in rigid methylcyclohexane glasses, while the proportion of lower-energy 4–5 increases increasing amounts 2-methylbutane glass. In both isopentane 77°K benzene solution room temperature, only spectrum evident. higher-energy ascribed to n,π* triplets rigidly held ground state conformations, assigned conformationally-relaxed triplets.