Synthesis and liquid-crystal behavior of metal-free and metal-containing phthalocyanines substituted with long-chain amide groups

The synthesis and characterization (by optical microscopy, differential scanning calorimetry (DSC), X-ray diffraction) of two series of octasubstituted lipophilic phthalocyanines 1-3 and 4-7, bearing amide functions in the peripheral chains, are reported. Compounds 1-3, 6, and 7 exhibit a liquid-crystal phase, for which a hexagonal columnar structure is proposed on the basis of the X-ray studies. The number of peripheral hydrocarbon chains and the possibility of hydrogen bonding is shown to have a critical influence on mesomorphism in these compounds.