Investigation of the photophysical and photochemical behavior of substituted zinc phthalocyanines and their water-soluble quaternized derivatives


Abstract: New nonperipherally and peripherally tetrasubstituted zinc(II) phthalocyanine complexes containing 1-benzylpiperidin-4-ol groups and their quaternized derivatives are reported in this work. These complexes were characterized successfully and their photophysical and photochemical properties were studied. These properties were determined in dimethylsulfoxide for all studied complexes and in water and water $+$ Triton X-100 solutions for ionic Zn(II) phthalocyanines. All studied zinc(II) phthalocyanine complexes generated high singlet oxygen, especially in dimethylsulfoxide, and these properties make them potential photosensitizers for use in the photodynamic therapy of cancer. The effects of the position and quaternization of the substituents on the photophysical and photochemical properties were also examined. The fluorescence of the tetrasubstituted zinc(II) phthalocyanine complexes is effectively quenched by addition of 1,4-benzoquinone. Furthermore, the water soluble Zn(II) phthalocyanines can bind to bovine serum albumin, which is a blood plasma protein.

Keywords: Phthalocyanine, quaternized, photodynamic therapy, photosensitizer, bovine serum albumin

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