Microsecond Flash Photolysis of 1, 3, 5-Trinitrobenzene Solutions and Product Formation with 254 nm Steady State Illumination

摘要

Flash photolysis of 1-3-5-trinitrobenzene(TNB) aerated solutions in alcohols generates a transient species with absorption maxima at 430 and 510 nm. The rate of transient formation is viscosity dependent. In deaerated solutions there is produced, instead of the transient, a brown permanent product, identified as a charge transfer complex with absorption maxima at 470 and 550 nm. These species are formed only in polar solvents with relatively high proton affinity. The data indicate that proton ejection from the lowest excited triplet state of TNB leads to the anion of the ground state molecule, which reacts with oxygen, in aerated solutions of alcohols, to form the transient species while in deareated alcohols the anion reacts with the solvent fo form RO(-) which leads to the charge transfer complex RO----(-)TNB. This mechanism is supported by detailed kinetic and spectroscopic studies. With 254 nm light, a nitroso derivative is formed in polar and nonpolar solutions of TNB.