title: Photochemical and photosensitizing properties of monomeric and dimeric Sn(IV)-protoporphyrin.
abstract: 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.
authors.affiliation: Department of Biology, University of Padova, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Reddi
authors.forename: G
authors.initials: G
authors.lastname: Jori
authors.forename: F F
authors.initials: FF
authors.lastname: Rubaltelli
mesh_terms: D008665:Metalloporphyrins / Q000737:chemistry*; D011524:Protoporphyrins / Q000737:chemistry*; D011838:Radiation-Sensitizing Agents / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D013053:Spectrophotometry; D013329:Structure-Activity Relationship
chemical_list: D008665:Metalloporphyrins; D011524:Protoporphyrins; D011838:Radiation-Sensitizing Agents; C032628:tin protoporphyrin IX