Sulfur Bridged New Metal-Free and Metallo Phthalocyanines Carrying 1,2,4-Triazole Rings and Their Photophysicochemical Properties

Abstract

The novel metal-free (4 ) zinc(II) (5), lead(II) (6), cobalt(II) (7) and copper(II) (8) phthalocyanines containing 1,2,4-triazole groups connected to the phthalocyanine ring by S-bridge were synthesized and characterized. For this purpose, the original 2-(4-chlorobenzoyl)-N-(4-fluorophenyl)hydrazinecarbothioamide (1) was synthesized as a result of the reaction of 4-chlorobenzyl hydrazide and 4-fluorophenyl isothiocyanate. It was obtained 5-(4-chlorophenyl)-4-(4-fluorophenyl)-4H-1,2,4-triazole-3-thiol (2), which is a new compound by the ring closure reaction of 1. The other original compound 4-[5-(4-chlorophenyl)-4-(4-fluorophenyl)-4H-[1,2,4]triazol-3-yl sulfanyl]-phthalonitrile (3) was synthesized by the nucleophilic aromatic substitution reaction of 4-nitrophthalonitrile and compound 2. Starting from the new phthalonitrile (3), the metal-free (4), zinc(II) (5), lead(II) (6), cobalt(II) (7) and copper(II) (8) phthalocyanines were prepared. Totally eight new compounds were synthesized, and their structures were characterized by 1H NMR, 13C NMR, FT-IR, MALDI-TOF MS and UV-vis spectral data in this work. The photophysical and photochemical properties of the synthesized phthalocyanines were investigated for determination of their usability as photosensitizers for photodynamic therapy applications. Thus, remarkable results were obtained.