Investigation of photophysical, photochemical and bovine serum albumin binding properties of novel water-soluble zwitterionic zinc phthalocyanine complexes

The non-peripherally tetra-(1a), peripherally tetra-(2a) and peripherally octa-(3a) zwitterionic zinc(II) phthalocyanine complexes bearing 2-(N-propanesulfonic acid)mercaptopyridine groups have been synthesized for the first time. These novel complexes have been characterized by elemental analysis, UV–vis, IR and 1H NMR spectroscopy and mass spectra. These zwitterionic complexes show excellent solubility in water, which makes them candidate photosensitizers for use in photodynamic therapy (PDT) of cancer. The photophysical (fluorescence quantum yields and lifetimes) and photochemical (singlet oxygen and photodegradation quantum yields) properties of synthesized zwitterionic zinc(II) phthalocyanine complexes were investigated in DMSO and phosphate buffered solution (PBS). This study also presented the water soluble zwitterionic zinc(II) phthalocyanines strongly bind to blood plasma proteins such as bovine serum albumin (BSA).