Oxygen, phthalocyanine photosensitization

Photooxidafions are also iudustriaHy significant. A widely used treatment for removal of thiols from petroleum distillates is air iu the presence of sulfonated phthalocyanines (cobalt or vanadium complexes). Studies of this photoreaction (53) with the analogous ziuc phthalocyanine show a facile photooxidation of thiols, and the rate is enhanced further by cationic surfactants. For the perfume iudustry, rose oxide is produced iu low toimage quantifies by singlet oxygen oxidation of citroneUol (54). Rose bengal is the photosensitizer. 

Like the porphyrins, the phthalocyanines can undergo photooxidation and act as photosensitizers for the production of singlet oxygen" One of the few chemical synthetic applications was the acceleration of the autoxidation of cumene and photooxidation of pinenes". ... 

The situation is different for zinc(II) phthalocyanines. A classic study on zinc(II)phtha-locyanine 3 shows that it is an efficient photosensitizer for singlet oxygen with a quantum... 

Some of the key properties of a photosensitizer are high efficiency of singlet-oxygen generation, strong absorption in the red and particularly near-IR (660-800 nm), preferential affinity for tumor rather than healthy tissue, and rapid clearance from the body. Porphyrin and phthalocyanine dyes fit these criteria best, and much work has been done on these dye types [76], Photofrin, a hemato-porphyrin derivative, was the first photosensitizer to be approved for clinical use. It is a complex mixture of monomeric porphyrins (protoporphyrin, hematopor-phyrin (84), and hydroxyethylvinyldeuteroporphyrin) and oligomers of these porphyrins. 

Krasnovsky et al. reported the first visible luminescence derived from singlet oxygen produced by protoporphyrin photosensitization in solution. Along with the "monomol" luminescence at 1270 nm, visible luminescence with intensity proportional to the square of the excitation power was observed. Certain compounds such as naphthalocyanines and phthalocyanines give luminescence with extremely high efficiency one of the most effective is tetra-r rr-butyl phthalocyanine (Pc). The spectrum of the... 

We now report time-resolved and steady-state measurements of phthalocyanine luminescence sensitized by singlet oxygen dimols, produced both by photosensitization and by thermal processes the detailed kinetics strongly support Scheme 2. 

Michelsen et al. reported a new class of cationic photosensitizers 466 for PDT. These unsymmetrical substituted benzonaphthoporphyrazines are synthesized to have one to eight positive charges. The Q-band transition exhibits a red shift from 680 to 760 nm dependent upon the number of annealed naphthalene rings. The singlet-oxygen yields of these compounds are normally higher compared with zinc phthalocyanine. 

Murtinho, D., Pineiro, M., Pereira, M. et al. (2000). Novel Porphyrins and a Chlorine as Efficient Singlet Oxygen Photosensitizers for Photooxidation of Naphthols or Phenols to Quinones, J. Chem. Soc. Perkin Trans., 2, pp. 2441-2447 Sorokin, A. and Tuel, A. (1999). Heterogeneous Oxidation of Aromatic Compounds Catalyzed by Metallophthalocya-nine Functionalized Silicas, New J. Chem., 23, pp. 473-476 Sorokin, A., Mangematin, S. and Pergrale, C. (2002). Selective Oxidation of Aromatic Compounds with Dioxygen and Peroxides Catalyzed by Phthalocyanine Supported Catalysts, J. Mol. Catal. A Chem., 182-183, pp. 267-281. 

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