Photophysical properties of glucoconjugated chlorins and porphyrins and their associations with cyclodextrins

Glucoconjugated analogues of the meta-hydroxyphenyl porphyrin (m-THPP) and meta-hydroxyphenyl chlorin (m-THPC) has been recently synthesized. The characteristics of their triplet states have been determined with regard to their involvement in the photodynamic (PDT) efficiency. In the case of porphyrin derivatives, triplet quantum yields (phi(T)) were ranging from 0.42 to 0.55 and triplet life times (tau(T)) from 1 to 5 mu s. High reaction rate constants (k(q)) with molecular oxygen (k(q): 1.2-1.6 x 10(9) s(-1)) have been found. The triplet lifetimes of chlorin derivatives were about four times higher than those of porphyrins whereas the phi(T) and k(q) values remained quite similar. Singlet oxygen yields of glucosylated and non-glucosylated porphyrins and chlorins were not significantly different within experimental errors (phi(Delta)(O-1(2)): 0.41-0.58). Furthermore, it has been shown that glucoconjugated photosensitizers could undergo associations with the methyl-p-cyclodextrin (Me-beta-CD) which exhibit high triplet lifetimes and singlet oxygen yields ranging from 0.27 to 0.48. (c) 2005 Elsevier B.V. All rights reserved.