**Porphyrins and Phthalocyanines: Photosensitizers and Photocatalysts**

Rodica-Mariana Ion

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doi:10.1073/pnas.0504598102

188 Phthalocyanines and Some Current Applications

doi:10.1021/jp071546b

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/intechopen.68654

#### Abstract

The porphyrins and phthalocyanines are among the most representative macrocycles in synthetic chemistry, characterized by specific molecular structures, responsible and associated with their particular properties. They have high versatility and an adequate variability introduced either by macrocycle metallation or by different substituents at its periphery called meso-substituents. The porphyrins could find, together with the synthetic phthalocyanines, various scientific and technological applications in chemical and photochemical areas. They can serve as catalysts and photocatalysts in different reactions, or as photosensitizers in photodynamic therapy of cancer, due to their high efficiency to generate free radicals and excited state species. The aim of this chapter is to achieve a better understanding of the complex and various properties of the porphyrins and phthalocyanines in different solvents or in heterogeneous media, trying to draw the relationships between these topics with their possible applications in catalytic, photocatalytic area (photodegradation of Kraft-lignin, photooxidation of different unsaturated hydrocarbons, photodegradation of different organic aquatic pollutants, oxirans polymerization) and some preliminary results about the heterogeneous porphyrin sensitizers in the photodynamic therapy area. Their photobleaching mechanisms in different conditions are also discussed.

Keywords: porphyrins, phthalocyanines, catalysis, photocatalysis, photosensitization, photodynamic therapy
