Discotic liquid crystals of transition metal complexes. Part 35. Establishment of a unique mesophase in bis(octaalkoxyphthalocyaninato)lutetium(iii) complexes

Abstract

A series of the bis(octaalkoxyphthalocyaninato)lutetium(III) complexes [(C_nO)₈Pc]₂Lu (n = 10, 12, 14, 16, 18) were synthesized. The mesomorphic behaviour was revealed by using polarization microscopy and DSC. The detailed mesophase structures were clarified by using temperature-dependent X-ray diffraction and temperature-dependent electronic absorption spectroscopy techniques. It was found that each of the Lu complexes shows a special rectangular ordered columnar (Col_ro) mesophase and a normal hexagonal (Col_h) columnar mesophase. It was established that the special Col_ro mesophase gave two different stacking distances (h_t and h_f) which originate from both trampoline movement and rotation of the phthalocyanine disks.