Photophysical Properties of Crowned Porphyrins


  • Posted on the website on 25 April 2005

*To whom correspondence should be addressed: Departamento de Química, Faculdade de Filosofia Ciências e Letras, Universidade de São Paulo, Ribeirão Preto-SP, Brazil. Fax: 55-16-6338151; e-mail:


In this study, we evaluated the photophysical properties of 5, 10, 15, 20-tetrakis[4-(1, 4, 7, 10, 13-pentaoxacyclopentadecane-2-aminomethyl) 2, 3, 5, 6-(tetrafluoro)-phenyl]-porphyrin (H2C4P) and Zn(II)5, 10, 15, 20-tetrakis [4-(1, 4, 7, 10, 13-pentaox-acyclopenta-decane-2-aminomethyl) 2, 3, 5, 6-(tetrafluoro)-phenyl]-porphyrinate (ZnC4P). We observed that these porphyrins have unique properties when compared with classical porphyrins. The porphyrins H2C4P and ZnC4P showed efficient transfer energy S1 to T1 by intersystem crossing with high and reasonable yields of triplet excited state and singlet oxygen production. These amphiphilic structures of these porphyrins could improve its localization in the tumor cells due to the presence of the crown ether in its framework. We also believed that the crown ether could modulate the change in ion homeostase (Ca+2, K+, Na+) as already described by some new phthalocyanine dye. This fact makes us believe that it could be reasonably used as a photosensitizer for PDT purposes.