Temperature Dependent Fluorescence of ‘Tunable Fluorophore-Fissile Bond’ Systems Based on 1-Phenyl, 3-Aryl Δ2-Pyrazolines as a Means of Quantitating Photofission Processes

Abstract

Abstract The activation energy for the C(5)-N(1) bond homolysis in the lowest excited singlet state of the 1-Phenyl, 3-Aryl, 5-(2′Phenylethenyl) Δ2-pyrazolines as deduced from the temperature dependence of the fluorescence quantum yield (ΦF) can be combined with the corresponding singlet energy to give a constant value of 75.5 kcal mol−1 as the total photofission energy. The corresponding value for 1,3-Diphenyl, 5-(2′-Iodo phenyl) Δ2-pyrazoline significantly exceeds the bond dissociation energy (BDE) of the aryl carbon-iodine linkage.