The synthesis of some phthalocyanines and napthalocyanines derived from sterically hindered phenols

The synthesis of a number of phthalocyanines (Pcs) and naphthalocyanines (NPcs) bearing bulky substituents is described. Precursors are prepared by using a nucleophilic aromatic substitution reaction between a sterically hindered phenol and 4-nitrophthalonitrile, 3-nitrophthalonitrile 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 macrocycle. In particular, the Pc derived from 2,6-di-tert-butyl-4-methylphenol 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-active phenolic substituents.