Photothermal reactions of nitrosobenzene and halonitrosobenzenes in solid-state

Abstract

Photothermal reactions of the dimers of nitrosobenzene, m-chloronitrosobenzene, and p-chloronitrosobenzene were studied in solid-state by IR spectroscopy at low temperatures and by X-ray powder diffraction. It was found for the first time that photothermal cycle (photolytic dissociation fol-lowed by thermal dimerization) could successively be performed also with Z-configured dimeric nitroso-benzene. Halonitrosobenzenes dimers with E-configuration afforded different photo behavior depending on the po-sition of halogen atom on the benzene ring: while m-halonitrosobenzenes do not dissociate under UV ir-radiation, p-chloronitrosobenzene, as well as previously studied p-bromonitrosobenzene photolyses very efficiently with recovering of the original crystal phase. Kinetics of thermal dimerization was measured in solid-state, and it was found that the reaction phase transformation occurs as a two-dimensional growth through the crystal.