Octa-alkoxy phthalocyanine and naphthalocyanine derivatives: dyes with Q-band absorption in the far red or near infrared

Abstract

The lithium alkoxide-catalysed cyclic tetramerisation of various 3,6-dialkoxy-4,5-dichlorophthalonitriles, 1,4-dialkoxynaphthalene-2, 3-dicarbonitriles and 3,6-dialkoxyphthalonitriles to give the corresponding metal-free octa-alkoxyoctachlorophthalocyanines, octa-alkoxynaphthalocyanines and octa-alkoxyphthalocyanines is described. An unexpected trans-alkoxylation reaction occurs during the cyclisation of the first two series of precursors. Metal-free phthalocyanines and naphthalocyanines have been converted into derivatives containing various metal ions. Compounds show Q-band absorption in the region 739–862 nm in toluene solution. The fluorescence spectra of selected examples are reported. The solubility of some of the compounds has been measured in a formulation of liquid crystal materials.