Synthesis, characterization and singlet oxygen generation studies of surface-tethered triazatriangulenium cations

The synthesis of heterogeneous supported sensitizers has gained much attention in recent times and has found various applications in areas including photosensitized disinfection of waste water, taking into account their advantages over the homogeneous photosensitizers. Among the heterogeneous sensitizers, silica gel supported organic dyes have received great attention. In this paper we report the synthesis of heterogeneous supported sensitizers in which triazatriangulenium cation is covalently anchored on silica. The singlet oxygen sensitization capability of the triazatriangulenium-silica composites was monitored using the singlet oxygen probe disodium-9, 10-anthracenedipropionic acid (ADPA). The study of disinfection of water containing pathogenic bacteria was also carried out to determine the effectiveness of the prepared triazatriangulenium-silica composites for the waste water treatment. All the four types of synthesized triazatriangulenium-silica composites produced singlet oxygen, as it is evident from the photobleaching of singlet oxygen probe ADPA. The results of the disinfection studies using the four types of prepared triazatriangulenium-silica composites shows that these materials are effective in the killing of bacterial pathogens when used with light.