Synthesis and characterisation of some novel phthalocyanines containing both oligo(ethyleneoxy) and alkyl or alkoxy side-chains: novel unsymmetrical discotic mesogens

The synthesis of unsymmetrical, peripherally octa-substituted phthalocyanines which contain a combination of 1,4,7,10-tetraoxaundecyl and hexadecyl or dodecyloxy side-chains is described. These compounds were prepared by mixed phthalonitrile cyclotetramisations or by the self-condensation of an unsymmetrical phthalonitrile containing both dodecyloxy and 1,4,7,10-tetraoxaundecyl groups. Separation of phthalocyanine products was achieved by simple column chromatography. A number of isomeric phthalocyanines, separated as single compounds, are reported. All of the phthalocyanines possess thermotropic columnar liquid crystallinity and a brief summary of their mesogenic properties is given.