The effects of alkylthio chains on the properties of symmetric liquid crystal dimers.

Cruickshank, Ewan; Strachan, Grant J.; Majewska, Magdalena M.; Pociecha, Damian; Gorecka, Ewa; Storey, John M.D.; Imrie, Corrie T.

Abstract

The synthesis and characterisation of four series of symmetric liquid crystal dimers containing either alkylthio or alkyloxy terminal chains are reported. The (E,E)-[pentane-1,5-diylbis(oxy-4,1-phenylene)]bis{N-[4-(alkyloxy)phenyl]methanimine}s, mO.O5O.Om and (E,E)-[hexane-1,6-diylbis(oxy-4,1-phenylene)]bis{N-[4-(alkyloxy)phenyl]methanimine}s, mO.O6O.Om series are nematogenic when the terminal chains are short whereas the higher homologues show the smectic A phase. The mO.O6O.Om series shows higher clearing temperatures regardless of the terminal chain length. The (E,E)-[pentane-1,5-diylbis(oxy-4,1-phenylene)]bis{N-[(alkylthio)phenyl]methanimine}s, mS.O5O.Sm series is solely nematogenic, and does not show liquid crystallinity when m ≥ 5. The (E,E)-[hexane-1,6-diylbis(oxy-4,1-phenylene)]bis{N-[(alkylthio)phenyl]methanimine}s, mS.O6O.Sm series, however, shows mesogenic behavior over the entire series, with the smectic C phase only emerging when the terminal chain is long, m ≥ 8. In general, for a given spacer length, the dimers containing alkyloxy chains show the highest clearing temperatures and the alkylthio chains the lowest. For the shortest terminal chains, however, the nematic–isotropic transition temperatures of the alkylthio materials are higher than those containing the alkyl chain. This behaviour is rather general and discussed in terms of steric and electronic interactions.

Citation

CRUICKSHANK, E., STRACHAN, G.J., MAJEWSKA, M.M., POCIECHA, D., GORECKA, E., STOREY, J.M.D. and IMRIE, C.T. 2023. The effects of alkylthio chains on the properties of symmetric liquid crystal dimers. New journal of chemistry [online], 47(15), pages 7356-7368. Available from: https://doi.org/10.1039/D2NJ06252F

• Journal Article Type: Article
• Acceptance Date: Mar 17, 2023
• Online Publication Date: Mar 20, 2023
• Publication Date: Apr 21, 2023
• Deposit Date: Aug 8, 2023
• Publicly Available Date: Aug 8, 2023
• Journal: New Journal of Chemistry
• Print ISSN: 1144-0546
• Electronic ISSN: 1369-9261
• Publisher: Royal Society of Chemistry
• Peer Reviewed: Peer Reviewed
• Volume: 47
• Issue: 15
• Pages: 7356-7368
• DOI: https://doi.org/10.1039/D2NJ06252F
• Keywords: Alkylthio chains; Symmetric liquid crystal dimers; Molecular modelling; X-ray diffraction
• Public URL: https://rgu-repository.worktribe.com/output/2010311
• Related Public URLs: https://rgu-repository.worktribe.com/output/2035113 (Supplementary material association with journal article)