Electropolymerized phenothiazines for the photochemical generation of singlet oxygen

The selected group of five amine-derivative phenothiazines was used to form their electropolymerized films in aqueous acidic solution with the aim to assess their ability to generate singlet oxygen. The films were characterized using cyclic voltammetry, UVVis spectroelectrochemistry, and Raman spectroscopy. The data of all the films were compared with properties of their monomer analogs. It was demonstrated that the electrochemically prepared films similarly to the known process of the corresponding monomers in solution phase are able to generate singlet oxygen in a photochemical surface process activated by laser radiation. These photogeneration process of the short-living species was monitored using the selected trap, which is detectable using UVVis spectroscopy. The effectiveness of the surface photogeneration reaction for each polymeric structure was determined in terms of half-life of the trap decay. The presented heterogeneous process of singlet oxygen photogeneration is believed to extend the area of applications of that highly oxidative reactant as compared to known homogeneous systems employing unbounded active species.