Photochemical and photosensitizing properties of monomeric and dimeric Sn(IV)-protoporphyrin

✍ Scribed by Elena Reddi; Giullio Jori; Firmino F. Rubaltelli

• Book ID: 103993190
• Publisher: Elsevier Science
• Year: 1991
• Tongue: English
• Weight: 611 KB
• Volume: 8
• Category: Article
• ISSN: 1011-1344
• DOI: 10.1016/1011-1344(91)80054-l

✦ Synopsis

Sn(IV)-protoporphyrin IX (Sn-Pp) in aqueous media exists as a mixture of monomeric and dimeric species, which can be readily distinguished on the basis of their absorption maxima at around 410 and 386 nm respectively. Sn-Pp dimers prevail as the pH is decreased and are characterized by a lower fluorescence quantum yield, a larger tendency to undergo photobleaching and a reduced photosensitizing efficiency compared with the Sn-Pp monomer. The photosensitizing action of Sn-Pp appears to involve the intermediacy of singlet oxygen (1O2) as shown by photo-oxidation studies with N-acetyl-tryptophanamide in light and deuterated water solutions. Using 1,3-diphenyl-isobenzofuran as a substrate, the quantum yield of 1O2 generation by monomeric Sn-Pp was found to be about 0.6.