Synthesis and liquid crystal properties of phthalocyanine derivatives containing both alkyl and readily oxidised phenolic substituents

The synthesis, using a mixed phthalonitrile cyclotetramisation, of phthalocyanine derivatives containing both long alkyl side-chains and redox-active, sterically hindered phenolic (3,5-di-tert-butyl-4-hydroxyphenyl) substituents is described. A detailed structural characterisation, including high resolution NMR spectroscopy, revealed that the statistically predicted amounts of regioisomers were prepared for each compound. Some isomers could be isolated using a combination of column chromatography and HPLC. A detailed investigation of their thermotropic mesophase behaviour is reported, including X-ray diffraction structure determination. These compounds are designed to combine interesting oxidative behaviour with liquid crystalline properties.