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Article

Twist-Bend Nematogenic Supramolecular Dimers and Trimers Formed by Hydrogen Bonding

1
Department of Chemistry, School of Natural and Computing Sciences, University of Aberdeen, Scotland AB24 3UE, UK
2
Faculty of Chemistry, University of Warsaw, ul. Zwirki i Wigury 101, 02-089 Warsaw, Poland
3
Chemical and Materials Engineering Group, School of Engineering, University of Aberdeen, Scotland AB24 3UE, UK
*
Author to whom correspondence should be addressed.
Crystals 2020, 10(3), 175; https://doi.org/10.3390/cryst10030175
Received: 10 February 2020 / Revised: 27 February 2020 / Accepted: 3 March 2020 / Published: 6 March 2020
(This article belongs to the Special Issue Early Career Stars of the Decade)
A selection of novel non-symmetric supramolecular liquid crystal dimers and trimers formed by hydrogen-bonding have been prepared and their phase behaviour characterised by polarised optical microscopy, X-ray diffraction and temperature-dependent Fourier-transform infrared spectroscopy. We mix the bent twist-bend nematogen 4-[6-(4’-cyanobiphenyl-4-yl) hexyloxy]-benzoic acid (CB6OBA) with a series of small stilbazole-based compounds 4-[(E)-2-(n-alkoxyphenyl)ethenyl]pyridines (nOS) of varying terminal chain length (n) to obtain the CB6OBA:nOS complexes. Complexes with n ≤ 7 exhibit nematic and twist-bend nematic behaviour, followed on cooling by a smectic C phase for n = 4–7, and finally, a hexatic-type smectic X phase for n = 3–7. Mixtures with n = 8–10 exhibit a smectic A phase below the conventional nematic phase, and on further cooling, a biaxial smectic Ab phase and the same hexatic-type SmX phase. Supramolecular trimers, CB6OBA:CB6OS and CB6OBA:1OB6OS, formed between CB6OBA and dimeric stilbazoles [(E)-2-(4-{[6-(4’-methoxy[1,1’-biphenyl]-4-yl)hexyl]oxy}phenyl)ethenyl]pyridine (1OB6OS) or 4-[(E)-4’-(6-{4-[(E)-2-(pyridin-4-yl)ethenyl]phenoxy}hexyl)[1,1’-biphenyl]-4- carbonitrile (CB6OS), exhibit nematic and twist-bend nematic phases, and are the first hydrogen-bonded trimers consisting of unlike donor and acceptor fragments to do so. View Full-Text
Keywords: liquid crystals; twist-bend nematic phase; hydrogen-bonding; supramolecular liquid crystals; supramolecular dimers; supramolecular trimers; spontaneous symmetry breaking liquid crystals; twist-bend nematic phase; hydrogen-bonding; supramolecular liquid crystals; supramolecular dimers; supramolecular trimers; spontaneous symmetry breaking
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MDPI and ACS Style

Walker, R.; Pociecha, D.; Martinez-Felipe, A.; Storey, J.M.; Gorecka, E.; Imrie, C.T. Twist-Bend Nematogenic Supramolecular Dimers and Trimers Formed by Hydrogen Bonding. Crystals 2020, 10, 175. https://doi.org/10.3390/cryst10030175

AMA Style

Walker R, Pociecha D, Martinez-Felipe A, Storey JM, Gorecka E, Imrie CT. Twist-Bend Nematogenic Supramolecular Dimers and Trimers Formed by Hydrogen Bonding. Crystals. 2020; 10(3):175. https://doi.org/10.3390/cryst10030175

Chicago/Turabian Style

Walker, Rebecca, Damian Pociecha, Alfonso Martinez-Felipe, John M. Storey, Ewa Gorecka, and Corrie T. Imrie 2020. "Twist-Bend Nematogenic Supramolecular Dimers and Trimers Formed by Hydrogen Bonding" Crystals 10, no. 3: 175. https://doi.org/10.3390/cryst10030175

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