Self-Assembled Columnar Structures of Swallow-Shaped Tetrathiafulvalene-Based Molecules

Abstract

A series of swallow-shaped tetrathiafulvalene (TTF)-based liquid crystal (LC) molecules (a-6TTFn, where 6 represents the number of carbon atoms in the two tails of a-6TTFn and n is the even number of carbon atoms in the alkyl chains attached to the side of the asymmetric TTF mesogen, n = 6−12) was designed and synthesized. One of this series of swallow-shaped asymmetric TTF molecules (abbreviated as a-6TTF12) having 12 carbon atoms in the alkyl chains attached to the side of the asymmetric TTF mesogen served as an example in this study. Major phase transitions and their origins in a-6TTF12 were studied with combined techniques of differential scanning calorimetry (DSC), one-dimensional (1D) wide-angle X-ray diffraction (WAXD) and solid-state carbon-13 (13C) nuclear magnetic resonance (NMR) experiments. a-6TTF12 formed a highly ordered liquid crystalline (ΦLC) phase at higher temperatures and a crystalline (ΦCr) phase at lower temperatures. On the basis of the experimental results, it was found that the hi...