Synthesis and liquid crystal properties of phthalocyanine bearing a star polytetrahydrofuran moiety

A new polymeric ligand, 6-(3,4-dicyanophenylthio)-hexyl-2-polytetrahydrofuranacetate (2) and its liquid crystalline polymeric phthalocyanine, 2,9,16,23-tetrakis-{6-(polytetrahydrofuran-2-carboxylate)-hexylthio-phthalocyaninatocobalt(II) (3), {CoPc(S-C₆H₁₃OCO-poly-THF)₄]}(CoPcLC) have been synthesized. The ligand and the phthalocyanine, bearing polytetrahydrofuran moieties (poly-THF), were characterized using elemental analysis, FTIR, ¹H and ¹³C NMR, and UV–Vis techniques. CoPcLC (3) promotes a greater interaction between the mesogens, resulting in solution aggregations together with a red-shift in the Q-band in the presence of the soft Ag⁺ ion. The dielectric anisotropy and phase transition temperature values of CoPcLC doped with 4-cyano-4′-n-pentylbiphenyl (5CB) were found to be 7.17 and 40.5 °C, respectively. The dielectrical anisotropy behaviour of the liquid crystals changes from the positive to the negative type. The current–voltage characteristics of the liquid crystals show a non-linear behaviour.