In 2022,Walker, Rebecca; Pociecha, Damian; Faidutti, Camilla; Perkovic, Eva; Storey, John M. D.; Gorecka, Ewa; Imrie, Corrie T. published an article in Liquid Crystals. The title of the article was 《Remarkable stabilisation of the intercalated smectic phases of nonsymmetric dimers by tert-butyl groups》.SDS of cas: 17696-11-6 The author mentioned the following in the article:
The synthesis and characterization of two groups of nonsym. dimers, the 1-(4-cyanobiphenyl-4′-yloxy)-ω-(4-alkylbenzylidene-4′-oxy)alkanes and the 1-(4-cyanobiphenyl-4′-yl)-ω-(4-alkylbenzylidene-4′-oxy)alkanes, are reported. The length and parity of the flexible spacer are varied. The tert-Bu homologues show higher m.ps. than the corresponding sec-Bu or Bu substituted dimers and suggesting that chain branching improves packing efficiency within the crystalline structure. The branched chain homologues have a stronger tendency to exhibit smectic phases than the n-butyl-substituted dimers and are exclusively smectic for longer spacers. A comparison of the nematic-isotropic transition temperatures (TNI) for the dimers and containing the different terminal chains is possible for one set of materials, and reveals a large reduction in TNI on passing from the Bu to sec-butyl-substituted, but a much smaller decrease on changing sec-Bu for tert-Bu. A different trend is observed for the smectic A-isotropic transition temperatures for which the tert-Bu substituted dimers and show a higher value than the corresponding sec-Bu homolog, and only marginally lower than that of the n-butyl-substituted dimers. This surprising behavior is interpreted in terms of the ability of the tert-Bu group to pack more efficiently into the intercalated smectic A phase as the spacer length increases. In the experiment, the researchers used 8-Bromooctanoic acid(cas: 17696-11-6SDS of cas: 17696-11-6)
8-Bromooctanoic acid(cas: 17696-11-6) acid is used in the synthesis of 8-(N-Methyl-4,4′-bipyridinyl)- octanoic acid. 8-Mercaptooctanoic acid was prepared from 8-bromooctanoic acid.SDS of cas: 17696-11-6
Referemce:
Bromide – Wikipedia,
bromide – Wiktionary