Achiral unsymmetrical four-ring bent-core liquid crystals with a polar fluoro or chloro end substituent: synthesis and characterisation

Study of phase transitions in a bent-core liquid crystal probed by infrared spectroscopy

“…The interatomic distance between N53 and H52 is 1.740 Å that supports the strong intramolecular interaction of NÁ Á ÁÁ Á ÁH which is in agreement with the previously reported work [22]. The molecular length and bent angle are measured as $ 44 Å and $143 , respectively and well supported by previous studies on bent-core molecules [23].…”

Impact of terminal polar substitution on elastic, electro-optic and dielectric properties of four-ring bent-core nematic liquid crystals

“…24 Salamon et al reported another thiadiazole based BCN with K 33 > K 11 and the non-BCN behavior was assigned to the four alkyl chains connected to intermediate core rings which act like so spacers between molecules and prevents close polar packing. 41 However in our case the bend angle is identical ($146 ) for all the compounds 29,30 and hence it cannot be the dominant parameter in governing the elastic constants. Also the molecules do not have any lateral alkyl chains which may prohibit formation of polar clusters.…”

Synthesis and structure of lateral halogenated V-shaped liquid crystal molecules based on a 1,7-naphthalene central core and alkylthio tails

“…There are some relevant reports showing that the type and position of substituent have evidently influence on the mesogen behaviour of bent-shaped molecules. [21][22][23][24] Certainly, some research have indicated that the introduction of the halogen substituent to the position of the terminal benzene could significantly decrease the phase transition temperatures and improve phase range. [25,26] In this study, we separately prepared lateral fluorinated or chlorinated V-shaped molecules based on 1,7-dioxynaphthalene with alkylthio tails (Scheme 1) to observe their mesomorphic state and transition temperature.…”