Supramolecular liquid crystals displaying competitive hydrogen bonding: Mesogenic associative chain structures using rigid and flexible pyridyl groups was written by John, Eric A.;Heltne, Michael D.;Bornowski, Evan C.;Lindberg, David J.;Carli, Joshua D.;Legare, Seth B.;Carli, John T.;Wiegel, Kurt N.. And the article was included in Molecular Crystals and Liquid Crystals in 2019.Reference of 626-64-2 This article mentions the following:
A series of liquid-crystalline supramol. copolymers formed through hydrogen bonding has been created. These polymers are composed of a bis-benzoic acid and two different pyridyl species – a small rigid bispyridyl capable of forming a mesophase when assembled and one of a pair of flexible bis pyridyl non-mesogenic “disruptor” species. The latter set of mols. consist of the pyridyl functionality separated by six or ten methylene units (6BPD and 10BPD, resp.). It was found that the associative chain polymers display monotropic characteristics depending upon the length of the methylene spacer group. The hexamethylene chain produced smectic phases up to 15% composition and cleared nematic characteristics at 70% loading. The decamethylene species eliminated smectic phases at 5% loading and displayed nematic phases up to 40% inclusion. It is believed that the increased length and flexibility of the alkyl chain allows for too much conformational mobility and freedom to efficiently form liquid-crystalline phases at high concentrations In the experiment, the researchers used many compounds, for example, Pyridin-4-ol (cas: 626-64-2Reference of 626-64-2).
Pyridin-4-ol (cas: 626-64-2) belongs to pyridine derivatives. Pyridine is diamagnetic and has a diamagnetic susceptibility of −48.7 × 10−6 cm3·mol−1.The molecular electric dipole moment is 2.2 debyes. The standard enthalpy of formation is 100.2 kJ·mol−1 in the liquid phase and 140.4 kJ·mol−1 in the gas phase. Halopyridines are particularly attractive synthetic building blocks in a variety of cross-coupling methods, including the Suzuki-Miyaura cross-coupling reaction.Reference of 626-64-2