Synthesis of new water soluble phthalocyanines and investigation of their photochemical, photophysical and biological properties

With the quaternized derivatives (4a and 5a), the synthesis of new Zn(II) and Co(II) phthalocyanines (4 and 5) substituted with 2-(azepan-1-yl)ethoxy moieties are reported. Photochemical and photophysical properties of quaternized Zn(II) and Co(II) phthalocyanines (4a and 5a) are investigated in both dimethyl sulfoxide (DMSO) and water, while non ionic derivatives in DMSO only. General trends are described for fluorescence quantum yields, fluorescence lifetimes, singlet oxygen quantum yields and photodegradation quantum yields. In this work, the effect of substituents and the nature of the metal atoms on the photochemical and photophysical parameters of new phthalocyanines are discussed. The quaternized compounds exhibit excellent solubility in water, making them potential photosensitizers for use in photodynamic therapy (PDT) of cancer. This study also showed that the water-soluble quaternized Zn(II) phthalocyanines strongly bind to blood plasma proteins such as bovine serum albumin (BSA).