The first comparison of photophysical and photochemical properties of non-ionic, ionic and zwitterionic gallium (III) and indium (III) phthalocyanines

The spectroscopic, aggregation properties, photophysical and photochemical behaviour of 3-hydroxypyridine substituted gallium (III) and indium (III) phthalocyanine complexes and their quaternized ionic and zwitterionic derivatives are investigated and compared for the first time. The quaternized ionic and zwitterionic phthalocyanine complexes show excellent solubility in water, which makes them potential photosensitizer for use in photodynamic therapy (PDT) of cancer. Photophysical and photochemical properties of photosensitizers are very important for determination of these complexes as PDT agents. Especially, the singlet oxygen quantum yields give an indication of the efficiency of potential photosensitizers in PDT applications. The studied phthalocyanine complexes (3–8) have good singlet oxygen quantum yields. This study also presented the water soluble gallium (III) and indium (III) phthalocyanines strongly bind to blood plasma proteins such as bovine serum albumin (BSA).