- Preparation and properties of high birefringence phenylacetylene isothiocyanato-based blend liquid crystals
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A series of compounds of with high birefringence containing alkoxy–phenylacetylene–isothiocyanato structure were synthesized and characterized. The chemical structures of these compounds were confirmed by FT-IR and 1H-NMR, and transition temperatures and birefringence were measured. One of these compounds with good liquid crystal property and high birefringence was mixed with host liquid crystal to form blend liquid crystal. The effects of the concentration of the compound on phase temperature range, birefringence, resistivity, dielectric anisotropy and photoelectric properties were discussed. The results showed that blend liquid crystal (with 7 wt% compound) exhibited excellent comprehensive performance.
- He, Zemin,Wang, Haiyang,Zhang, Huimin,Zhang, Yongming,Zhao, Yang,Zhao, Yuzhen
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- An Additive-Free, Base-Catalyzed Protodesilylation of Organosilanes
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We report an additive-free, base-catalyzed C-, N-, O-, and S-Si bond cleavage of various organosilanes in mild conditions. The novel catalyst system exhibits high efficiency and good functional group compatibility, providing the corresponding products in good to excellent yields with low catalyst loadings. Overall, this transition-metal-free process may offer a convenient and general alternative to current employing excess bases, strong acids, or metal-catalyzed systems for the protodesilylation of organosilanes.
- Yao, Wubing,Li, Rongrong,Jiang, Huajiang,Han, Deman
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p. 2250 - 2255
(2018/02/23)
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- Synthesis of diphenyl-diacetylene-based nematic liquid crystals and their high birefringence properties
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We synthesized two series of diphenyl-diacetylene (DPDA)-based materials with alkoxy and alkyl tails of length m (DPDA-OCm and DPDA-Cm, respectively), and measured their nematic-phase birefringence (Δn) as a function of wavelength and temperature. We found that Δn decreases with an increase in m, possibly by a dilution effect of the low-Δn alkyl tail. Further, of the two series, Δn was found to be relatively higher in the DPDA-OCm materials, with the highest value of 0.4 obtained for DPDA-OC1 at 550 nm at 10 °C below the isotropic-to-nematic transition temperature. Further, we observed the temperature dependence for Δn, which is proportional to the order parameter (s). From extrapolation to s = 1 (the perfect orientation state), it is speculated that the DPDA-O moiety has the potential to afford a very large Δn of 0.9. The Royal Society of Chemistry 2012.
- Arakawa, Yuki,Nakajima, Shunpei,Ishige, Ryohei,Uchimura, Makoto,Kang, Sungmin,Konishi, Gen-Ichi,Watanabe, Junji
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supporting information; experimental part
p. 8394 - 8398
(2012/07/28)
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- High birefringence nematic liquid crystals for display and telecom applications
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Several compounds with high birefringence and, having tolane structure were synthesized. For a high polarizability, isothiocyanato (NCS) terminal group was introduced. Another goal of this study was reduction of melting point and smectic phases by introduction of fluorine as lateral substituent. The transition temperatures for all the synthesized compounds and the refractive and dielectric indices for one of the compounds have been determined. Electro-optic (EO) measurements were also performed.
- Catanescu, Carmen Otilia,Chien,Wu, Shin-Tson
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p. 93/[1135]-102/[1144]
(2007/10/03)
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