Synthesis and photophysical properties of a new cationic water-soluble Zn phthalocyanine.

The synthesis of tetrakis (1,1-dimethyl-2-trimethylammonium)ethylphthalocyaninato Zn(II) tetraiodide 2--a new cationic phthalocyanine--is reported as well as its photophysical properties in water, relevant for the use of this dye as photodynamic sensitizer. The hydrophobicity of the macrocycle leads to strong aggregation which lowers the fluorescence and singlet oxygen quantum yields of aqueous solutions of 2. Photophysical parameters agree with those of other Zn phthalocyanines when correction is performed for the fraction of light absorbed by the monomer.