Induction of the cholesteric mesophase in nematic liquid crystals: correlation between the conformation of open-chain chiral 1,1'-binaphthyls and their twisting powders

Helical Polyacetylene: Asymmetric Polymerization in a Chiral Liquid-Crystal Field

“…These properties are attributed to large steric repulsions between hydrogens at the 8-and 8′-positions in the naphthyl rings. 107,111,148 It is also confirmed from this figure that the helical twisting power of the binaphthyl derivative slightly decreases with increasing temperature.…”

“…It has been clarified so far that the binaphthyl derivatives of (M)-and (P)-helicity induce N*-LCs with counterclockwise and clockwise twisting directions, respectively, when they are added as chiral dopants into a N-LC. 110,111,[177][178][179] The CD spectrum can be interpreted in terms of the exciton coupling theory. [180][181][182] The sign and intensity of the CD couplet are related to the value of the dihedral angle (θ) between the two binaphthyl rings.…”

The Control of the Cholesteric Pitch by Some Azo Photochemical Chiral Switches

“…[21][22][23] We have also studied m-bis(azo)benzene derivatives 5 and 6 with chiral pendant groups in the hope of obtaining induction of an helical structure of the foldamer type [24] and hence, possibly, high helical twisting powers. Compound 7 was synthesised to observe better effects due to the restricted mobility of the system.…”

Rigid and Sterically Regular Chiral 1,1′-Binaphthyl Polymers in Asymmetric Catalysis

“…It has been previously observed that an optically active 2,2'-substituted 1,1'-binaphthyl molecule can exist in either cisoid or transoid conformation. [17][18][19][20] As shown in Figure 1, the cisoid conformation has a dihedral angle of less than 908 between the two naphthyl rings and the transoid conformation greater than 908. Molecules containing 2,2'-substituents that are either small or capable of intramolecular hydrogen bonding prefer the cisoid conformation.…”