A hypervalent iodine secondary oxidant synthesized by photosensitized singlet oxygen: Synthesis, characterization and oxidative reactivity

Abstract

Chemical scavenging of singlet oxygen by iodobenzene in the presence of (triethyleneglycol)monomethyl ether led to the formation of almost spherical nano-structured iodosylbenzene in water, water/acetonitrile and acetonitrile. To our knowledge, it is the first report on the direct aerobic photooxidative synthesis of iodosylbenzene. A polymer supported cationic porphyrin, nanoAmbSO3@H2TMPyP, was used as the photosensitizer. The nanoparticles, were characterized by various spectrophotometric and microscopic methods. The reactivity of the secondary oxidant for the oxidation of organic substrates was studied in the oxidation of methyl phenyl sulfide catalyzed by manganese meso-tetrakis(2-methylphenyl)porphyrin.The synthesis of the reactive secondary oxidant, PhIO, is suggested as anapplicablestrategy to overcome the problem of very short lifetime of singlet oxygen in organic solvents and water, which decreases the efficiency of singlet oxygen due to the involvement of the oxidant in unwanted physicalandchemicalquenchingpathways.It is noteworthy that due to very short lifetime of singlet oxygen, most of the singlet oxygen produced in the presence of different photosensitizers is deactivated by other species to return to its triplet ground state by physical or non-productive chemical quenching.