Photosensitized oxidation of bromide to bromine catalyzed by niobium pentachloride in methanol solution: Formation and crystal structure of the tetraphenylphosphonium tribromide

This article examines the photoproduction of bromine by UV–vis light irradiation in the presence of niobium pentachloride in methanol media, under aerobic conditions. The reaction of tetraphenylphosphonium bromide with niobium pentachloride in methanol, thus, produced the corresponding tribromide. X-ray studies were performed on the tribromide compound to confirm the oxidation reaction. To our knowledge, the homogeneous photocatalytic oxidation of halogen ions when niobium pentachloride is photosensitized is the first example of the photocatalytic properties of this reagent. The photo-oxidation of the halogen ions was carried out under several conditions. The nearly linear oxo-bridges seem to favour this photocatalytic action.