Photosensitizing properties of ionic porphyrins immobilized on functionalized solid polystyrene support

The photogeneration of singlet oxygen (1O2) by tetrasodium salt of meso‐tetrakis(4‐sulfonatophenyl)porphyrins (H2TPPS) and some of its metal complexes (MTPPS; M = Cd2+, Zn2+), immobilized on cationically functionalized polystyrene (PS) beads, was studied. The generation of 1O2 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 1O2 scavanger, providing evidence for the involvement of 1O2 as an active intermediate. The relative efficiencies of the generation of 1O2, 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–H2TPPS, PS–ZnTPPS, and PS–CdTPPS, respectively. Binding of porphyrins to a polymer has been found to decrease the efficiency of the 1O2 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