56955-73-8Relevant academic research and scientific papers
Lateral fluoro-substitution and chiral effects on supramolecular liquid crystals containing rod-like and H-bonded bent-core mesogens
Han, Chun-Chieh,Yang, Li-Han,Raghunath, Putikam,Lin, Ming-Chang,Kumar, Rohit,Lin, Hong-Cheu
, p. 110482 - 110492 (2016)
The first series of liquid crystalline supramolecular diads C/D containing asymmetric rod-like and H-bonded bent-core mesogens were designed and synthesised, among which supramolecular diad / with two chiral centers on both the H-acceptor/H-donor and non-lateral fluoride substitution possessed a wide blue phase (BPI) range of 13.7 °C. According to the molecular modeling, a large biaxial parameter (≥3.2) and an appropriate HTP value (4.2-4.8 μm-1) are the most important factors to stabilize the double twisted cylinder structure (i.e., BPI) in supramolecular diads. Moreover, the bent angles, biaxial parameters and dipole moments of supramolecular diads are mainly affected by the locations and numbers of H-bonds and chiral centers. Not only larger bent angles and biaxial parameters but also smaller dipole moments and HTP values were obtained by removing the lateral fluoride substitution on supramolecular diads to achieve the blue phase of / (without lateral fluoride substitution). Finally, the special optimal 1:1 molar ratio of supramolecular diad / (i.e., H-donor = 50 mol%) with the widest blue phase range is mainly attributed to its rod-like and H-bonded bent-core mesogens, rather than H-donor = 75 mol% in most supramolecular complexes containing linear H-bonded rod-like mesogens.
New chalcone based liquid crystals with allylidene amino linking unit: Synthesis and characterization
Sharma, Vinay S.,Sharma, Anuj S.,Jadeja, Upendra H.,Suthar, Deepak
, p. 64 - 81 (2019/02/24)
In this study, the synthesis, structural characterization and mesomorphic properties of newly thirteen calamitic shaped compounds derived from allylidene amino chalcone and 4-n-alkoxy benzoyloxy benzoic acid. Comp.H1 to H3 exhibited nonliquid crystalline nature, while comp.H4 to comp.H18 displayed enantiotropical smectic C phase. Phase transition temperatures of present synthesised compounds were determined by optical polarising microscopy (POM), differential scanning calorimetric (DSC) and powder X-ray diffraction (PXRD) techniques. Thermal stabilities of smectic to isotropic phase are 150.0 °C and temperature range of mesophase is in decreasing order from comp.H3 to comp.H18 respectively. The presences of SmC phase are the type of broken fan and needle type in present synthesized series. It is also shown that presence of chalcone amino allylidene central linking group favors a calamitic liquid crystalline behaviour in molecules with lower member to higher member aliphatic side chain in alkoxy group (-OR).
New hockey stick shaped amino allylidene (?N?CH?CH?CH) based compounds: Effect of linkage group on mesomorphic properties
Sharma, Vinay. S.,Vekariya, Rajesh. H.,Sharma, Anuj. S.,Patel
, p. 84 - 98 (2017/09/25)
Two nonlinear hockey stick shaped homologous series based on three linking groups have been synthesized and characterized by elemental analyses and spectroscopic techniques. The mesomorphic properties of these compounds were observed by polarizing optical microscopy (POM) and differential scanning calorimetry (DSC). In this present investigation, we have synthesized two homologous series viz. 2-((3-phenyl allylidene) amino) phenyl 4-((4-n-alkoxy benzylidene) amino) benzoate (series-1) and 4-((2-((3-phenyl allylidene) amino) phenoxy) carbonyl) phenyl-4-n-alkoxy benzoate (series-2). Both the series are differing with respect to first linking group. In series-1, comp.C4-C18 shows nematic as well as smectic phase while in series-2, comp.C10-C16 shows smectic and nematic phase while comp.C4-C18 shows only nematic phase.
Synthesis and mesomorphic properties of calamitic shaped molecules with chalconyl-ester and lateral fluoro substituents
Sharma, Vinay S.,Sharma, Anuj S.,Vekariya, Rajesh H.,Patel
, p. 32 - 44 (2018/03/21)
In this study we have synthesized a new class of compounds incorporating of chalcones and laterally substituted fluoro group. A series of new chalcones with five aromatic rings is synthesized and characterised by elemental analyses and spectroscopic techniques such as Fourier transform infrared [FT-IR] and proton magnetic resonance magnetic resonance [1H NMR] spectroscopy. The mesomorphic properties of these compounds were observed by optical polarized light microscopy (POM) and confirmed by differential scanning calorimetry (DSC). It is found that all the prepared materials display enantiotropic LCs phases except first three homologue in present series. The lower homologues (n = 4 to 12) display SmC and nematic phase while, in higher homologues (n = 14 to 18) only SmC phase were seen in heating and cooling condition.
Hierarchical superstructures with control of helicity from the self-assembly of chiral bent-core molecules
Lin, Shih-Chieh,Ho, Rong-Ming,Chang, Chin-Yen,Hsu, Chain-Shu
, p. 9091 - 9098 (2012/10/08)
Herein, two asymmetric chiral bent-core molecules, 3-[(4-{[4-(heptyloxy) benzoyl]oxy}benzoyl)oxy]-phenyl-4-[(4-{[(1R)-1-methylheptyl]oxy}benzoyl)oxy] benzoate (BC7R) and 3-[(4-{[4-(heptyloxy)benzoyl]oxy}benzoyl)oxy]-phenyl-4-[(4- {[(1S)-1-methylheptyl]oxy}benzoyl)oxy] benzoate (BC7S), were synthesized to demonstrate control of the helicity of their self-assembled hierarchical superstructures. Mirror-imaged CD spectra showed a split-type Cotton effect after the formation of self-assembled aggregates of BC7R and BC7S, thereby suggesting the formation of intermolecular exciton couplets with opposite optical activities. Both twisted and helical ribbons with preferential helicity that corresponded to the twisting character of the intermolecular exciton couplet were found in the aggregates. The formation of helical ribbons was attributed to the merging of twisted ribbons through an increase in width to improve morphological stability. As a result, control of the helicity of hierarchical superstructures from the self-assembly of bent-core molecules could be achieved by taking advantage of the transfer of chiral information from the molecular level onto the hierarchical scale.
Electro-optical switching studies on 1,3-phenylene based banana shaped liquid crystals
Balamurugan,Kannan,Yadupati,Roy
, p. 118 - 124 (2011/10/03)
This work deals with the study of the thermotropic liquid crystalline properties of new asymmetric bent core liquid crystals. The thermotropic properties was analyzed by polarized optical microscopy, differential scanning calorimetric analysis and variable temperature X-ray diffraction measurements. Effect of equal terminal chain with asymmetric bent core system on mesomorphic behavior was examined. The shorter methyl chain compound 10a of exhibits B 1 mesophase and higher homologs (10b and 10c) shows antiferroelectric B2 mesophases, which was studied by electro-optical measurements.
Chiral smectic *C mesogens having ester and amide central linkages
Tandel,Vora
, p. 103 - 116 (2008/09/20)
Ten members of a chiral homologous series 4-(4'-n-alkoxy benzoyloxy benzoyl)4''- S- (+) 2-methyl butoxy anilides were synthesized in multiple step synthesis. Series exhibits chiral smectic *C and cholesteric mesophases. In this series, n-propyl to n-dodecyl derivatives exhibit smectic *C and cholesteric mesophases. n-Tetradecyl and n-hexadecyl derivatives exhibit only smectic *C phases. The plot of transition temperatures versus number of carbon atoms in alkoxy chain exhibits odd-even effect for cholestric-isotropic transition temperatures. The effect of amide linkage and chirality is discussed in detail. High-temperature cholestric phases exhibit vivid colors. Two compounds were analyzed by calorimetric study (C12 and C14) to confirm the transition temperatures of which was observed under polarizing microscope. The mesogenic behavior of the series compared with other series where amide central linkage differs in its position. The mesogenic thermal stability is compared with other related homologous series. The result indicates that amide linkage enhances smectic as well as cholesteric thermal stability but enhancement in smectic phase is much higher. Compounds are characterized by elemental analysis, IR spectral data, Mass spectral data, DSC, NMR, and microscopic study.
Langmuir films of amphiphilic crown ethers
Heiney, Paul A.,Stetzer, MacKenzie R.,Mindyuk, Oksana Y.,DiMasi, Elaine,McGhie, Andrew R.,Liu, Hu,Smith III, Amos B.
, p. 6206 - 6214 (2007/10/03)
We have used X-ray reflectivity and grazing-incidence X-ray diffraction to study amphiphilic crown ethers 1 and 2 at the air-water interface. A new synthetic route was employed, which substantially reduced the level of impurities. Unlike previous studies of 1, we saw no evidence of a first-order lying-down to standing-up transition of the alkyl tails. We did observe in both compounds a gradual reorientation of the tails away from the interface as the film was compressed, followed by an irreversible collapse to a multilayer structure. The monolayer films have a fluid-like inplane structure, while the multilayer films are crystalline. ? 1999 American Chemical Society.
Calamitic organometallic liquid crystals with terminal metal. Syntheses and liquid crystal properties of dicarbonylrhodium(I) β-diketonate complexes
Wan, Wen,Guang, Wen-Jie,Zhao, Ke-Qin,Zheng, Wei-Zhong,Zhang, Liang-Fu
, p. 157 - 161 (2007/10/03)
A series of novel organometallic complexes based on γ-substituted β-diketone ligands with terminal metal Rh(I) have been prepared by reaction of the ligands with [Rh(CO)2(μ-Cl)]2. The mesomorphism of the ligands and complexes has been investigated using DSC and polarizing microscope. It is found that non-mesogenic ligands with n=7, 8, 9, 10, 11 can form liquid crystalline phase by direct coordination to metal. The effect of the terminal carbon number on the mesomorphism has also been discussed.
Nematic Liquid Crystal Containing Diaza-18-Crown Ether Unit
Minggui, Xie,Jun, Qin,Feng, Hong,Liangyu, Wang
, p. 309 - 318 (2007/10/02)
Three diaza-18-crown-6 carrying aryl ester structural unit were synthesized and shown to nematic liquid crystalline properties.The influence of the molecular structure on liquid crystalline properties was studied.It has been found that whether the complexes display liquid crystalline properties depends upon structure of anions.The influence of doping inorganic salt on the clear point was also studied.
