Synthesis, Characterization, Photophysical and Photochemical Properties of Novel Phthalocyanines

The benzothiazole substituted phthalonitrile (3) and non‐peripherally tetra benzothiazole substituted metal‐free ( 4 ), zinc(II) ( 5 ) and lead(II) phthalocyanine ( 6 ) complexes were prepared. The compounds (3‐6) were characterized by IR, NMR, UV‐Vis and mass spectroscopy data. After synthesis, photochemical and photophysical parameters of the compounds ( 4‐6 ) were analyzed to determine photosensitizer performance of them for PDT applications. Firstly, the most suitable solvent for compounds ( 4‐6 ) was found by aggregation studies. Then, fluorescence properties were measured in DMF at 1x10 −6  M. Singlet oxygen properties were measured in DMF by using 1,3‐diphenylisobenzofuran (DPBF) as a singlet oxygen quencher. Photodegradation properties were measured under light irradiation in DMF at 1x10 −5  M. The zinc(II) phthalocyanine ( 5 ) had the highest singlet oxygen production capacity (Φ ▵ =0.62), fluorescence (Φ F =0.25) and photodegradation quantum yield (Φ d =3.28x10‐4). The results showed that zinc(II) phthalocyanine ( 5) has potential for photodynamic therapy applications.