Flying-seed-like mesogens 6: Synthesis and mesomorphism of phthalocyanine derivatives substituted by pentafluorosulfanylphenoxy group

Abstract

We have synthesized two novel phthalocyanines, (m-SF[Formula: see text]PhO)[Formula: see text]PcCu (7b) and (p-SF[Formula: see text]PhO)[Formula: see text]PcCu (7c), in order to investigate their flying-seed-like mesomorphism. Their phase transition behavior and the mesophase structure have been established by using a polarizing optical microscope, a differential scanning calorimeter, and a temperature-dependent small angle X-ray diffractometer. Very interestingly, the derivative (m-SF[Formula: see text]PhO)[Formula: see text]PcCu (7b) substituted a SF5group at [Formula: see text]-position showed a Col[Formula: see text](P21/a) ([Formula: see text] p2gg) mesophase from rt to 315.0[Formula: see text]C, whereas the derivative (p-SF[Formula: see text]PhO)[Formula: see text]PcCu (7c) substituted a SF5group at [Formula: see text]-position showed a crystalline (K) phase from rt to the decomposition temperature at ca. 336[Formula: see text]C without showing mesomorphism. Thus, the novel phthalocyanine derivative (m-SF[Formula: see text]PhO)[Formula: see text]PcCu (7b) substituted a strong electron withdrawing SF5group at [Formula: see text]-position shows only one columnar mesophase in a very wide temperature region from rt to 315.0[Formula: see text]C. Furthermore, the Q-band wavelengths (672.2 and 672.1 nm) of the present (m-SF[Formula: see text]PhO)[Formula: see text]PcCu (7b) and (p-SF[Formula: see text]PhO)[Formula: see text]PcCu (7c) are shorter than that (680.3 nm) of the previous [(m-C[Formula: see text])PhO][Formula: see text]PcCu (5c) derivative. It can be attributed to strong electron withdrawing nature of the SF5group on the phenoxy group.