Efficiency of singlet oxygen generation from the triplet states of nitrophenyl ethers

Abstract

The bimolecular rate constants for oxygen quenching, k O 2 T and the quantum yields of singlet oxygen production, Δ, for 4-nitroveratrole, 4-nitroanisole and 3-nitroanisole triplet states in air-equilibrated deuterated water and acetonitrile solutions were determined where possible from nanosecond laser flash photolysis and time-resolved O 2 ( 1Δ g) phosphorescence measurements. The results show that the efficiency of singlet oxygen production, ƒ ΔT, for 4-nitroveratrole and 3-nitroanisole is moderately high and is related with the nature of the low-lying triplet state and that 4-nitroanisole is not able to sensitize singlet oxygen under these conditions.