Intra- and intermolecular interactions in mesogenic cyano compounds

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.…”

“…The lattice structure of the CP phase is monoclinic but the detail molecular arrangement is still not well understood. 5,18 Most of the previous studies on stable and metastable crystal phases of 8OCB were carried out on solution crystallised samples. 10,16,18 Jakli et al studied a metastable crystal state of 8OCB obtained by cooling the sample from its melt and identied the observed metastable phase as needle crystal phase.…”

Implementing Liquid‐Crystalline Properties in Single‐Stranded Dinuclear Lanthanide Helicates

“…Further insight into the organisation of the cyanobiphenyl units at the interface can be gained by monitoring the C≡N stretching vibration (ν CN ) during the crystal–liquid to isotropic liquid phase transitions 26. Interestingly, ν CN is particularly sensitive to changes in intermolecular CN ··· CN interactions that occur at the phase transitions27 but the temperature dependence (20–200 °C) of both frequency (ν CN [cm –1 ]) and integrated intensities ( I CN in the 2200 to 2250 cm –1 range)28 of the CN stretching band in [Y 2 ( L6 )(hfac) 6 ] during the isotropisation process shows no abrupt variation (Figures S27 and S28 in the Supporting Information) except during the first heating, in which cocrystallised water molecules are expulsed (Figures S29–32 in the Supporting Information).…”

Sulphur as a Structural Element in Calamitic Liquid Crystals: Terminal, Linking and Lateral Substitutions

“…However, the C 1 ÀN distance in phenylisocyanide is shorter than C 1 -C 7 distance in benzonitrile [35,37]. It can be proposed that these geometrical and electronic structures of the isothiocyanato, thiocyanato, isocyanato, cyanato, isocyano, and cyano groups [5,[29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48] affect through intra- [49][50][51] and intermolecular [52][53][54][55][56] interactions the molecular packing and consequently the …”