Phthalocyanines

Abstract

The phthalocyanines represent the most important chromophoric system developed during the 20th century. In 1928, in the manufacture of phthalimide by Scottish Dyes (later part of ICI) the formation of a blue impurity was observed in certain production batches from the reaction of phthalic anhydride with ammonia in a glass-lined reactor; the compound proved to be iron phthalocyanine (FePc). Following this discovery, the colour manufacturing industry was quick to recognise the unique properties of the compounds and to exploit their commercial potential. The phthalocyanines have subsequently emerged as one of the most extensively studied classes of compounds because of their intense, bright colours, their high stability, and their unique molecular structure. This chapter covers the structure and properties of phthalocyanines and their synthesis.