Photochemically-induced ligand exchange reactions of ethoxy-oxo-molybdenum(V) tetraphenylporphyrin in chlorinated solvents

Photochemically-induced ligand exchange reactions of ethoxy-oxo-molybdenum(V) 5,10,15,20-tetraphenylporphyrin, Mo(V)O(TPP)OEt, under irradiation at the Soret band region, were investigated. The reactions were performed in chlorinated solvents and followed with ultraviolet–visible (UV–vis) spectroscopy, whereas the products were analyzed with Fourier transformed infrared (FTIR) spectroscopy, electron spin resonance (ESR) spectroscopy and gas chromatography (GC). The chloro-oxo(TPP)Mo(V) complex was obtained as the final product, where the chlorine came from the solvent. Nevertheless, these reactions were not photocatalytic, due to the photochemical inertness of the formed chloro-oxo complex, and an excess of ethanol could not initiate a new photocatalytic cycle unless water was added as well, resulting in the formation of a biphasic system. On the other hand, addition of ethanol, water and NaOH to the reaction medium led to the formation of the corresponding oxo Mo(IV) complex. The studied photoassisted reactions of oxo Mo(V) porphyrins appear attractive for possible applications in the detection of chlorinated pollutants in sensing devices, but also for the dechlorination of pollutants upon suitable optimization of processing conditions.

Graphical abstractThe photoassisted ligand exchange reactions of oxomolybdenum(V) porphyrins in view of possible technological applications and especially in the area of sensing devices or pollutant dechlorination, have been investigated. We report on the photochemically-induced ligand exchange reactions of the ethoxy-oxo(TPP)Mo(V) complex, mainly in chlorinated solvents and secondarily in non-chlorinated solvents.Figure optionsDownload full-size imageDownload as PowerPoint slide