THE SYNTHESIS OF SOME PHTHALOCYANINES AND NAPTHALOCYANINES DERIVED FROM STERICALLY HINDERED PHENOLS

The synthesis of a number of phthalocyanines (Pcs) and naphthalocyanin es (NPcs) bearing bulky substituents is described. Precursors are prep ared by using a nucleophilic aromatic substitution reaction between a sterically hindered phenol and 4-nitrophthalonitrile, 3-nitrophthaloni trile or 6-fluoro-2,3-napthalonitrile. Thus, Pcs and NPcs derived from 2,6-diisopropylphenol, 3,5-di-tert-butylphenol and 2,6-diphenylphenol possess substituents that are forced by steric constraints to adopt a non-planar conformation which enhances the solubility of the macrocyc le. In particular, the Pc derived from 2,6-di-tert-butyl-4-methylpheno l displays exceptional solubility and a reduced tendency to aggregate in solution. 2,6-Di-tert-butylphenol reacts as a carbon nucleophile to produce biphenyl phthalonitrile precursors to Pcs containing redox-ac tive phenolic substituents.