Water soluble novel phthalocyanines containing dodeca-amino groups

Water soluble metal phthalocyanines (where the metal is Co, Cu or Pd) as well as a cationic Pd phthalocyanine, each bearing 12 dimethylamino groups to enhance solubility, were prepared. A phthalonitrile derivative was synthesized by the reaction of 4-nitrophthalonitrile with 2,4,6-tris(N,N-dimethylaminomethyl)phenol. Solution studies indicated that phthalocyanines containing tertiary amine substituents were monomeric only in acidic medium (pH < 6) whereas the quaternized dye was monomeric at all pH values. The electrochemical behavior of the phthalocyanines was investigated by cyclic voltammetry and differential pulse voltammetry. Spectroelectrochemical measurements were carried out to confirm assignments made to the metallophthalocyanines. All compounds were characterized by UV–vis, FT-IR, 1H NMR spectroscopy, mass spectrometry and elemental analysis.