A diaxial complex (triad) of Sn(IV)-5,10,15,20-tetra(4-sulfophenyl)porphyrin with Rose Bengal (RB), coordinated to the porphyrinate through the carboxyl group of a xanthene dye [SnP(RB)2], was synthesized. Its luminescent properties were studied at different excitation wavelengths in an aqueous medium at different pH values, as well as in a binary solvent of water-glycerol. The pH ranges in which the triad fluorescence exhibits the highest sensitivity upon excitation of its individual fragments were established. It was found that only the RB fragment exhibits a “rotary” fluorescent ability in SnP(RB)2. The ability of SnP(RB)2 to generate singlet oxygen was studied. The antibacterial effectiveness of SnP(RB)2 and its individual fragments was assessed against bacterial strains: Staphylococcus aureus ATCC 6538-P FDA 209-P, Escherichia coli M-17, and Candida albicans ATCC 10,231, both in the dark and under irradiation at different wavelengths. The processes of free radical degradation of blood cell membranes in the presence of the studied compounds and their cytotoxicity were also investigated.
