Further Evidence for the Triplet Mechanism in the Photosubstitution of Nitroaryl Ethers in Alkaline Medium.

Article abstract of DOI:10.1016/S0040-4020(01)89887-2

Mechanistic studies show that nitroaryl ethers (3-nitroanisole, 3-nitrophenetole, n-butyl 3-nitrophenyl ether, 2-chloro-5-nitroanisole, 2-bromo-5-nitroanisole and 3,5-dinitroanisole) undergo nucleophilic aromatic photosubstitution with hydroxide ions through an S_N2³Ar* mechanism.An investigation of the quenching of excited states of nitroaryl ethers by bromide and thiosulfate ions in aqueous solutions is reported and lends support to the proposed S_N2³Ar* mechanism.Key Words: Photosubstitution; Nitroaryl Ethers; Triplet Lifetime; Quencher.