Water soluble 1,2,3-triazole based metal-free, zinc(II) and indium(III) phthalocyanines: Synthesis, characterization, photochemical and photophysical properties

A series of novel water-soluble metal-free, zinc(II) and indium(III) (triethylene glycol methyl ether)-1H-1,2,3-triazole substituted phthalocyanines (Pcs) were synthesized and characterized using a range of spectroscopic techniques. The photophysical and photochemical properties, including singlet oxygen generation and photo-degradation quantum yields, were determined in order to assess the effect of the substituent and central metal ions on the spectroscopic and photophysicochemical properties of the Pcs. The production of singlet oxygen was found to be dependent on the structure of the phthalocyanine (Pc), the metal ion incorporated within the phthalocyanine cavity, and the solvent. The indium(III) phthalocyanine exhibited the highest singlet oxygen generation capability, with a singlet oxygen quantum yield (Phi Delta) of 0.87, 0.23 and 0.74 in DMSO, water and water-Triton X-100 mixture, respectively. All the Pcs demonstrated high stability against decomposition under light irradiation, with a photodegradation quantum yield (Phi d) in the range of 10-5. The indium(III) phthalocyanine presents a promising potential as a Type II photosensitizer candidate for photodynamic therapy in cancer treatment.