Synthesis, molecular, and photophysicochemical characterizations of phthalocyanine dyes containing sodiumsulfonatenaphthalen-2-olate groups

In this study, novel highly water-soluble 6-sodiumsulfonatenaphthalen-2-olate substituted phthalocyanines from the organic near-infrared dye class and contained zinc(II) or indium(III) metal ions in their cavity, were designed, and synthesized to explore their potential use as photosensitizers in photodynamic therapy. The molecular structures of the starting materials and dyes were characterized using elemental analysis, FT-IR, UV-vis, 1H-NMR, 13C-NMR, and MALDI-TOF mass spectrometry. The solubility and aggregation behaviors of these phthalocyanine dyes have been investigated in polar solvent types such as dimethylsulfoxide and N,Ndimethylformamide, ethanol, methanol, and water, as well as in phosphate-buffered saline. They have high solubility in the studied solvents and do not show any tendency to aggregate, except for water. Their photophysical and photochemical properties were investigated in N,N-dimethylformamide. The influence of the presence and position of substituents on their macrocyclic and the nature of the metal species in their cavities on their photophysical and photochemical parameters were reported. The fluorescence properties of the zinc(II) dyes studied were enhanced, while those of indium(III) dyes were low but sufficient as photosensitizers. The suitable and sufficient photophysicochemical properties of the water-soluble near-infrared new phthalocyanine dyes denote they can be potential candidates as Type II photosensitizers for photocatalytic applications.