Phase transitions, conformational lability, and intermolecular interactions in alkoxycyanobiphenyls

Crystal polymorphism of 8OCB liquid crystal consisting of strongly polar rod-like molecules

“…1,2 In the last few decades different phases of dipolar nOCB liquid crystal homologs have been investigated, where n denotes the number of carbon atoms in the terminal aliphatic chain attached to one end of the biphenyl core of the molecule. [3][4][5][6][7][8][9] These rod-like molecules have a strong dipole moment along their long axis due to the presence of the nitrile (CN) group attached to the other end of the biphenyl core of each molecule. 3 In this family of liquid crystals, the compounds 8OCB (4 0 -octyloxy-4-cyanobiphenyl) and 9OCB (4 0nonyloxy-4-cyanobiphenyl) with intermediate chain length show both smectic and nematic phases.…”

4-propoxy-biphenyl-4-carbonitrile Nematik Sıvı Kristalinin Dielektrik Özellikleri

“…2 kHz'de statik dielektrik geçirgenlik değeri, dielektrik geçirgenlik değerinden bir miktar yüksektir. Büyük dielektrik artış, -CN grubu tarafından oluşturulan daha büyük boyuna dipol momentten kaynaklanır [11,21,23,[26][27][28]. Fenil halkalar, -CN ( = 4.05D) ve C-O ( = 0.8D) gruplar elektronik bulutunun oksijen atomundan azot atomuna geçişine neden olurlar.…”

“…Alkoksi zinciri, diğer molekülün polar-CN grubundaki azottan önemli ölçüde daha fazla gerilmez. Her molekül, uzun ekseni boyunca önemli ölçüde yönlendirilen dipol momenti ile karakterize edilir [7,11,21,27]. Çünkü X-ışını kırınım çalışmaları -CN grubunun güçlü dipol momentleri nedeniyle çekirdek bölgelerin üst üste bindiğini göstermiştir [18,31,32].…”

Conformational analysis of alkyl- and fluoroalkylcyclohexanecarboxylic acids by infrared spectroscopy methods

“…JR spectra of some carboxylic acid derivatives have been measured in the spectral range of 33-4000 cm' and the temperature interval of 77-500 K and presented in works [1][2][3][4]. The mentioned temperature interval includes regions of solid crystal.…”

“…The analysis of nACHCA and nFACHCA experimental spectra, measured at temperature increasing from 100 to 500 K, has shown [1][2][3][4] that several spectral regions contain some changes in the band shapes and intensities, band peak shifts, as well as an appearance of new bands, the number of which grows with the homologue number increasing. Significant changes of nFACHCA JR spectra at temperature increasing and phase transitions have been observed in the spectral regions of 700-1500, 1700 and 2400-3600 cm'.…”