Papers by Keyword: Chiral

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Authors: Qiong Wu, Jing Lu, Xiao Lin Ji, Tao Yu Zou, Zhen Fang Qiao, Hong Ping Ju, Hai Wang
Abstract: Modifying polyoxometalates with organic and/or metal-organic moieties is a widely adopted method for broading the range of properties. In this work a new polyoxometalate constructed from Anderson-type polyoxoanions and L-arginine (Arg = L-arginine) molecules Na [CrMo6(OH)6O18]}(H2Arg)2·8H2O(1) has been synthesized via conventional method and characterized by routine techniques. Single-crystal X-Ray diffraction analysis shows that compound 1 is constructed by chiral L-arginine grafted Anderson-type clusters, sodium cation and water molecules which are further stabilized by hydrogen bonding interactions constitute 3D supramolecular networks. In addition, both antitumor behavior and photocatalytic activities of compound 1 were investigated.
335
Authors: Liang Min, Guo Liang Xu, Yi Min Liu, Wen Hua Yao
Abstract: After the invention of mesoporous, the chiral mesoporous materials had been regarded a hot research issue. Inspired by the chiral phenomenon, in this investigation, we presented several aspect of chiral mesoporous from its first appearance, especially stated the template that could be used to prepare chiral mesoporous, including chiral template and achiral template, besides, the different mechanism of some distinguished scientists’ works were introduced, and some application of these material were introduced such as catalyst, HPLC stationary phases and many other fields.
391
Authors: Liang Min, Guo Liang Xu, Yi Min Liu, Wen Hua Yao
Abstract: After the invention of mesoporous material, the chiral mesoporous materials had been regarded as a hot research issue. Inspired by the chiral phenomenon, in this investigation, we presented several aspect of chiral mesoporous material from its first appearance, especially stated the template that could be used to prepare chiral mesoporous material, including chiral template and achiral template, besides, the different mechanisms and several distinguished scientists’ works were introduced, and some application of these material were introduced such as catalyst, HPLC stationary phases and many other fields.
210
Authors: Zhi Xin Xu, Li Gao, Dan Shu Yao, Xiao Zhi He, Mei Tian
Abstract: In order to explore the effect of ionic groups on the properties of the liquid-crystalline polymers, a series of new main-chain liquid-crystal ionomers (LCIs) were prepared from sebacoyl chloride (SD), brilliant yellow (BY) and various amount of 4, 4-Dihydroxy-2, 2-dimethyl Benzalazine (DDBA) and isosorbide (ISO). The structures of the polymers were characterized by FT-IR and UV spectroscopies. Differential scanning calorimetry (DSC) was used to measure the thermal properties of the polymers. The mesogenic properties were investigated by polarized optical microscope (POM), differential scanning calorimetry and X-ray diffraction measurements. The results show that the LCIs are chiral smectic C (SC*) and nematic (N) LCIs exhibiting broken focal-conic texture and schlieren texture. The introduction of ionic units in the LCIs led to the clearing point and mesogenic temperature range increasing and the glass-temperature decreasing, but did not affect the mesogenic type and texture, as compared with the corresponding polymer P0.
39
Authors: Chang Du, Nai Yu Zhou, Dan Liu, Fan Bao Men
Abstract: Chiral fluorinated side-chain liquid-crystalline elastomers (LCEs) IP - IVP were graft copolymerized by hydrosilylation reaction. The chemical structure, liquid-crystalline behavior and polarization property were characterized by use of various experimental techniques. The effective crosslink density of the chiral LCEs was studied by swelling experiments. All the samples IP - IVP displayed chiral smectic C mesophase (SC*) on heating and cooling cycles. With increasing chiral crosslinking units in the elastomer systems, the glass transition temperature and chiral smectic C mesophase-isotropic phase transition temperature of fluorinated elastomers increased slightly, indicating that the temperature range of SC* mesophase became narrow with increase of chiral crosslinking agents for all the chiral fluorinated elastomers. All the samples IP - IVP showed 0.12-0.16 μC/cm2 of spontaneous polarization.
37
Authors: Mei Tian, Lu Lu Guo, Dan Shu Yao, Jian She Hu, Xiao Zhi He, Hong Guang Wang
Abstract: A series of main-chain liquid-crystalline polymers containing maltose were synthesized by interfacial condensation reactions of sebacyl chloride, 4,4’-Dihydroxy-2,2’-dimethyl Benzalazine(DDBA), and 1-O-[4´-O-(α-D-glucopyranosyl)-ß-D-glucopyranosyl]-methanol(MM). The effects of MM on characteristics of liquid-crystalline properties were studied. P1- P3 exhibited nematic mesophase on heating and cooling cycle, while P4- P7 exhibited both chiral smectic A and nematic mesophases on heating cycle and nematic mesophase on cooling cycle. P8 did not exhibit any mesophase on heating and cooling cycle. The glass-transition temperature decreased with increasing concentration of MM.
1218
Authors: Xiao Zhi He, Li Jiao Zhang, Guang Yu Li, Mei Tian, Ying Gang Jia
Abstract: A new series of two-arm (MB1, MB2), four-arm (MB3), six-arm (MB4) chiral liquid crystalline compound containing isosorbide as chiral core were first synthesized. Four precursors of branched-arm B1~B4 were obtained at first and then were esterized separately with isosorbide and got four chiral branched-arm liquid crystals (MB1~MB4). The chemical structures and LC properties of the liquid crystalline molecule were measured by spectrum and thermal analysis techniques. XRD curves of MB1~MB4 samples only showed broad peaks at wide-angle, but no sharp peak was seen for all the samples. The results showed that MB1~MB4 appeared cholesteric phase with oily streak texture or lined texture and finger print texture. Isosorbide successfully induced cholesteric phase. The values of melting point and clearing point for MB1~MB4 decreased. The quantity of branched-arm and chiral core had effects on their liquid crystalline properties.
1203
Authors: Zhi Yong Yang, Jin Shui Yao, Rui Bao Guo
Abstract: A novel chiral poly(amide imide) containing L-alanine was synthesized by direct polycondensation reaction of newly synthesized N,N’-(4,4’-diphthaloyl)-bis-L-alanine diacid with 4,4’-diaminodiphenyl ether in a medium consisting of N-methyl-2-pyrrolidone (NMP), triphenylphosphite (TPP), calcium chloride (CaCl2), and pyridine. The new chiral diimide-diacid monomer was synthesized by direct reaction of 3,3’-4,4’-Biphenyl tetracarboxylic acid dianhydride with L-alanine in acetic acid under refluxing conditions. The resulting compounds were obtained in quantitative yields and high purity. The synthetic diacid monomer was characterized by elemental analysis, 1H-NMR spectroscopy, FT-IR techniques and specific rotation, the obtained polymer was characterized by FTIR techniques, specific rotation and solubility testing.
116
Authors: Feng Yan, Ying Li, Ze Hui Li
Abstract: Make 5-methoxy-2-mercapto-imidazo[4,5-b]pyridine and 2-chloro-3,5-dimethyl-4-methoxy-pyridine hydrochloride as the starting materials, in alkaline conditions, use nucleophilic substitution to generate the prochiral sulfide: 2-[2-(4-methoxy-3 ,5-dimethyl-pyridine) methylmercapto]-5-methoxy-imidazo [4,5-b] pyridine. After recrystallization twice, gain the product with the yield of 80%, and the purity of 99.6% and above. Then make D-(-)-diethyl tartrate and tetraisopropyl titanate as the chiral reagents, in alkaline conditions, use cumene hydroperoxide oxide to oxidize prochiral sulfide, for synthesis of (S)-Tenatoprazole, and the results showed that when, the reaction temperature was , and reaction time was 20h, the result was the best.
384
Authors: Jian She Hu, Yi Nan Liu, Ya Ting Song, Di Wang
Abstract: To study the structure-property relationships of new chiral liquid crystalline materials based on menthol and explore their potential applications, a monomer 4-(4-allyloxybenzoyloxy) phenyl-4-menthyl-oxyacetyloxybiphenyl-4-carboxylate (LCM) and the corresponding homopolymer (LCP) were synthesized. The chemical structure was characterized by FT-IR and 1H NMR. The liquid crystalline properties were investigated by differential scanning calorimetry, thermogravimetric analysis, polarizing optical microscopy, and X-ray diffraction. The monomer LCM formed a cholesteric phase when a flexible linkage chain was inserted between the mesogenic core and the terminal menthyl groups by reducing the steric effect. The homopolymer LCP exhibited a batonnet texture of a smectic A phase.
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