Photosensitizing properties of ionic porphyrins immobilized on functionalized solid polystyrene support

Abstract

Abstract The photogeneration of singlet oxygen ( 1 O 2 ) by tetrasodium salt of meso ‐tetrakis(4‐sulfonatophenyl)porphyrins (H 2 TPPS) and some of its metal complexes (MTPPS; M = Cd 2+ , Zn 2+ ), immobilized on cationically functionalized polystyrene (PS) beads, was studied. The generation of 1 O 2 was monitored by a N , N ‐dimethyl‐4‐nitrosoaniline (RNO) bleaching assay. The rate of RNO bleaching was seen to be retarded in the presence of DABCO, a specific 1 O 2 scavanger, providing evidence for the involvement of 1 O 2 as an active intermediate. The relative efficiencies of the generation of 1 O 2 , with respect to immobilized rose bengal (PS–RB), by different polymer‐supported porphyrins, were determined to be 0.29, 0.27, and 0.16 for PS–H 2 TPPS, PS–ZnTPPS, and PS–CdTPPS, respectively. Binding of porphyrins to a polymer has been found to decrease the efficiency of the 1 O 2 generation, which could be attributed to the structural deformation of the appended porphyrins. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3925–3930, 2003