2c05 Discotic Liquid Crystals of Organic Metal Complexes (109) : Parity effect of the number of d-electrons on stacking distances in the columnar mesophases of octakis(m-alkoxyphenoxy)phthalocyaninato metal(II) complexes

Abstract

We have synthesized thirty-four novel homologous discotic liquid crystals, octakis(m-alkoxyphenoxy)phthalocyaninato metal(II) {abbreviated as (m-C_nOPhO)_8PcM (M=Co, Ni, Cu, Zn and H_2; n=8, 10, 12, 14, 16, 18 and 20)}, and investigated parity effect of the number of d-electrons on the stacking distances in their columnar mesophases. It was revealed from temperature-dependent wide angle X-ray diffraction studies that each of the cobalt(II) (d^7) complexes and the copper(II) (d^9) complexes showed a single hexagonal ordered columnar (Col_<ho>) mesophase with a very short stacking distance at 3.3Å, and that the nickel(II) (d^8) complexes and the metal-free (d^0) derivatives showed a single pseudo-hexagonal ordered columnar (Col_<rho>) mesophase with a little bit longer stacking distances at 3.4Å. Furthermore, the zinc(II) (d^<10>) complexes showed two different rectangular ordered columnar mesophases, Col_<ro>(P2/m) and Col_<ro>(P2_1/a), with a little bit longer stacking distance at 3.4Å.