A twist-bend nematic phase driven by hydrogen bonding

Suzanne M Jansze; Alfonso Martínez-Felipe; John M D Storey; Antonius T M Marcelis; Corrie T Imrie

doi:10.1002/anie.201409738

A twist-bend nematic phase driven by hydrogen bonding

Angew Chem Int Ed Engl. 2015 Jan 7;54(2):643-6. doi: 10.1002/anie.201409738. Epub 2014 Nov 17.

Authors

Suzanne M Jansze¹, Alfonso Martínez-Felipe, John M D Storey, Antonius T M Marcelis, Corrie T Imrie

Affiliation

¹ Department of Chemistry, School of Natural and Computing Sciences, University of Aberdeen, Meston Building, Aberdeen AB24 3UE (UK); Laboratory of Organic Chemistry, Wageningen University (The Netherlands).

PMID: 25403414
DOI: 10.1002/anie.201409738

Abstract

The liquid crystalline phase behavior of 4-[6-(4'-cyanobiphenyl-4-yl)hexyloxy]benzoic acid (CB6OBA) and 4-[5-(4'-cyanobiphenyl-4-yloxy)pentyloxy]benzoic acid (CBO5OBA) is described. Both acids show an enantiotropic nematic phase attributed to the formation of supramolecular complexes by hydrogen bonding between the benzoic acid units. In addition, CB6OBA provides the first example of hydrogen bonding driving the formation of the twist-bend nematic phase. The observation of the twist-bend nematic phase for CB6OBA, but not CBO5OBA, is attributed to the more bent molecular shape of the complexes formed by the former, reinforcing the view that shape is a key factor in stabilizing this new phase. Temperature-dependent FTIR spectroscopy reveals differences in hydrogen bonding between the two nematic phases shown by CB6OBA which suggest that the open hydrogen-bonded complexes may play an important role in stabilizing the helical arrangement found in the twist-bend nematic phase.

Keywords: hydrogen bonding; liquid crystal trimers; liquid crystals; supramolecular chemistry.