Preparation and in vitro photodynamic activities of novel axially substituted silicon (IV) phthalocyanines and their bovine serum albumin conjugates

Two novel axially substituted phthalocyanines, namely bis(4-(4-acetylpiperazine)phenoxy)phthalocyaninatosilicon (IV) (1) and its N-methylated derivative 2, have been synthesized. The dicationic phthalocyanine 2 is non-aggregated in water and exhibits good photophysical properties. The non-covalent BSA conjugates of these compounds have also been prepared. Compound 2 and the conjugate 2-BSA show extremely high photodynamic activities toward B16 melanoma cancer cell lines. The corresponding 50% growth-inhibitory (IC50) ratios are 33 and 38 nM, respectively.