The new water soluble zinc(II) phthalocyanines substituted with morpholine groups- synthesis and optical properties

Abstract Two new tetra- or octa-substituted zinc(II) phthalocyanines (1 and 2) bearing 3-(morpholinomethyl)phenyl groups were synthesized via Suzuki-Miyaura coupling method. These phthalocyanines (1 and 2) were converted to their water-soluble derivatives (1Q and 2Q) by quaternization of nitrogen atoms on the morpholine groups. The photochemical and photophysical properties of the non-ionic zinc(II) phthalocyanines (1 and 2) were explored in DMSO. On the other hand, these properties of the quaternized cationic derivatives (1Q and 2Q) were studied in both DMSO and aqueous solutions for determination of their photosensitizing capabilities in photodynamic therapy. The ct-DNA interaction of synthesized 1Q and 2Q were investigated and binding constants were found as 6.3 × 104 and 1.5 × 105 M, respectively. The binding constant values were found at similar levels of ethidium bromide (EB), which is a well-known intercalator. The spontaneous and exothermic nature of binding mechanisms were proved according to the calculated thermodynamic constants. Strong interactions of 1Q and 2Q with ct-DNA were also found with EB displacement assay and gel electrophoresis. Additionally, the bovine serum albumin (BSA) binding behavior of the new compounds (1Q and 2Q) were determined in water solution to verify the transporting capability of these phthalocyanines in the circulatory system and these values were found as 7.0 × 105 and 1.6 × 107 M−1 for 1Q and 2Q, respectively.