The determination of photophysical and photochemical parameters of novel metal-free, zinc(II) and lead(II) phthalocyanines bearing 1,2,4-triazole groups

[Display omitted] •Synthesis of substituted 1,2,4-triazole groups containing metal free- and metallo- phtalocyanines.•Investigation of aggregation properties of the phthalocyanines.•Investigation of photophysical and photochemical properties of the phthalocyanines. In this study the synthesis and characterization of novel phthalonitrile compound (3) and its metal-free (4), zinc(II) (5), and lead(II) (6) phthalocyanines bearing four 4-(4-methoxyphenylethyl)-5-propyl-2,4-dihydro-3H-1,2,4-triazol-3-one groups at peripheral positions were synthesized for the first time. These novel compounds were fully characterized by FT-FT-IR, 1H NMR, UV–vis and MALDI-TOF mass spectroscopic techniques. Their photochemical and photophysical properties were also investigated in N,N-dimethylformamide solutions. In addition, the effect of 4-(4-methoxyphenylethyl)-5-propyl-2,4-dihydro-3H-1,2,4-triazol-3-one groups as substituents and central metal ions (without metal, zinc(II) or lead(II)) in the phthalocyanine cavity on these properties were also compared. The studied zinc(II) or lead(II) phthalocyanines can be potential Type II photosensitizers for photodynamic therapy in cancer applications because these phthalocyanines showed good singlet oxygen generation and appropriate photodegradation.