- Development of nematic and orthogonal smectic phases in short-core fluorinated hockey-stick shaped liquid crystal compounds
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Here we report synthesis and investigations on novel short-core hockey-stick shaped molecules bearing a 4-n-alkyloxy-2-hydroxybenzylidene moiety at one end and polar fluoro-biphenyl moiety at the other end. The polar chloro and fluoro substituent at the lateral position of the core confers nematic and orthogonal smectic mesomorphism. The mesophase morphology is characterized by polarizing optical microscopy (POM), differential scanning calorimetry (DSC), X-ray diffraction (XRD), electro-optical study and dielectric spectroscopy. The fluorinated compounds 1b (n = 16) and 1c (n = 18) have long terminal hydrocarbon tail and show orthogonal smectic phases with antiferroelectric switching behaviour. The chlorinated compound 2e (n = 8) with relatively short terminal chain length exhibits only a monotropic nematic phase on cooling. The nematic phase is comprised of cybotactic clusters as confirmed by XRD and exhibits electro-optic switching. The compound 2i (n = 12) manifests a short range enantiotropic nematic and additional orthogonal smectic phase. Dielectric spectroscopy reveals polar correlations in the nematic and smectic phases.
- Upadhyaya, Kalpana,Ghosh, Sharmistha,Khan, Raj Kumar,Pratibha,Rao, Nandiraju V.S.
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- Efficient and recyclable bimetallic Co–Cu catalysts for selective hydrogenation of halogenated nitroarenes
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Silica supported N-doped carbon layers encapsulating Co–Cu nanoparticles (Co1Cux@CN/SiO2) were prepared by a one-step impregnation of Co(NO3)2·6H2O, Cu(NO3)2·3H2O, urea and glucose, following in situ carbothermal reduction. Effects of Cu contents on the catalytic performance of the Co1Cux@CN/SiO2 catalysts were investigated for selective hydrogenation of p-chloronitrobenzene to p-chloroaniline. The Co1Cu0.30@CN/SiO2 with Cu/Co molar ratio of 0.30:1 presented much higher activity and stability than the monometallic Co@CN/SiO2 catalyst. The addition of Cu into Co1Cux@CN/SiO2 catalysts had favorable effects on the formation of highly active Co–N sites and N-doped carbon layer. The role of the N-doped carbon layer was to protect the Co from oxidation by air, and the Co1Cu0.30@CN/SiO2 could be reused for at least 12 cycles without decrease in catalytic efficiency. Mechanistic and in situ infrared studies revealed that the interaction effect between the Co and Cu atoms made the surface of Co highly electron rich, which decreased adsorption of halogen groups and resulting in the enhanced selectivity during chemoselective hydrogenation of halogenated nitroarenes for a wide scope of substrates.
- Lu, Xionggang,Ren, Jiaan,Sheng, Yao,Wang, Xueguang,Wu, Baoqin,Zou, Xiujing
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- SUBSTITUTED QUINOLINES AND METHODS FOR TREATING CANCER
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Substituted quinoline compounds, methods of making such compounds, pharmaceutical compositions and medicaments comprising such compounds, and methods of using such compounds to treat, prevent or ameliorate cancer are provided.
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Paragraph 0378
(2018/05/24)
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- Rapid, efficient and selective reduction of aromatic nitro compounds with hydrazine hydrate in the presence of the plain and supported platinum nanoparticles as catalysts
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The current study aimed at application of the plain and supported platinum nanoparticles as a heterogenous catalyst for the reduction of aromatic nitro compounds. Monodispersed platinum nanoparticles were synthesized by reduction of H2PtCl6 by ethanol in the presence of polyvinyl pyrrolidone as a stabilizer, and then were immobilized on four types of zeolites. The obtained catalyst granules were characterized by X-ray diffractometry and transmission electron microscopy. The study then focused on elaboration of the catalytic activity of the nano catalysts under different operational conditions. It was found that reaction is adequately rapid at ambient temperature, and by utilizing a sufficient amount of catalyst, can be completed in nearly 30 min. Among the utilized zeolitic supports, zeolite 4A had the highest performance, but the mechanism of its synergetic effect on the activity of platinum nano catalyst was not found and requires more investigation.
- Mehdizadeh, Soofia,Ahmadi, Seyed Javad,Sadjadi, Sodeh,Outokesh, Mohammad
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p. 1587 - 1592
(2015/01/09)
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- A new family of four-ring bent-core nematic liquid crystals with highly polar transverse and end groups
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Non-symmetrically substituted four-ring achiral bent-core compounds with polar substituents, i.e.., chloro in the bent or transverse direction in the central core and cyano in the lateral direction at one terminal end of the molecule, are designed and syn
- Upadhyaya, Kalpana,Gude, Venkatesh,Mohiuddin, Golam,Nandiraju, Rao V.S.
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