Liquid crystalline alkylthia-substituted novel phthalocyanines: synthesis and characterization

Methylene-bridged tetra-and octa-alkylthia substituted metal free- and Ni(II) phthalocyanines were synthesized from the corresponding phthalonitrile derivatives in the presence of the anhydrous metal salt (NiCl2) or a strong organic base. The new compounds were fully characterized by elemental analyses, UV-vis, IR, NMR and mass spectra. The mesogenic properties of these materials were studied by differential scanning calorimetry, optical microscopy and X-ray diffraction investigations. X-ray diffraction patterns of the mesophase confirmed that the tetra-and the octa-substituted compounds formed hexagonal columnar mesophases (Col(h)). The mesogenic properties of these compounds were compared to that of their octa alkythia substituted phthalocyanine derivatives in the literature.