Synthesis and radiation sensitivity of phenoxazine type color formers including thiol ester protective group

Article abstract of DOI:10.1080/15421400590947126

3,7-Bis(N,N-diethylamino)-10-(phenylthio)carbonylphenoxazine (1a) and its analogs (1b-f) were synthesized and the color change after γ irradiation was investigated. The color change of acetonitrile solutions of 1a ([1a] ₀ = 1.0 × 10^-3 M) after γ irradiation was identified by naked eyes at the dose of 20 Gy. Phenylthio-substituted compound la showed more significant absorbance increase than phenoxy-substituted compound, 3,7-bis(N,N-diethylamino)-10-phenoxycarbonylphenoxazine (2a). The C-S cleavage in la by γ irradiation was revealed to occur more easily than the C-O cleavage in 2a. The sensitivity of the color formers 1a-f) to γ rays was correlated with the stability of the thiyl radicals generated in the reaction.