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1.
有玻璃态和液晶态的胆甾烯基苯并菲的合成及介晶性   总被引:1,自引:0,他引:1  
宋质琼  赵可清  胡平  汪必琴 《化学学报》2008,66(11):1344-1352
将盘状液晶基元苯并菲与手性向列型液晶基元胆甾烯基结合的化合物, 可望出现全新的性质. 合成了含有胆甾烯基的苯并菲化合物C18H6(OC5H11)5(OC5H10COOCh) (2), 2,7-C18H6(OC5H11)4(OC5H10COOCh)2 (4), C18H6(OR)3(OCnH2nCOO- Ch)3 (R=C5H11, C7H15, C9H19, C11H23, n=1, 5, 10) (6a~6f), C18H6(OC5H10COOCh)6 (Ch: cholesteryl) (8). 偏光显微镜和差示扫描量热法对这些化合物的热致介晶性研究结果显示, 化合物 4, 6a~6e具有手性盘状向列相和玻璃态, 8呈现近晶B相(SB)和玻璃态. 随间隔基长度n和烷基链R碳原子数的增加, 化合物玻璃化温度和清亮点呈下降趋势. 随着胆甾烯基数目减少, 化合物的玻璃化温度和清亮点降低.  相似文献   

2.
Connecting two discotic mesogens via a spacer not only stabilizes the columnar mesophase but also leads to the formation of glass columnar phase, and therefore improves the physical properties of discotic liquid crystals as organic semiconductor. Here, we report the synthesis of eight diacetylene-bridged triphenylene discotic liquid crystal dimers, [C18H6(OCnH2n+1)4(OMe)O2C-C8H16-C≡≡ C-]2, 3(n), (n = 4-8), [C18H6(OC6H13)5O2C-C8H16-C≡≡ C-]2, 6 and [C18H6(OC6H13)5O-(CH2)m-C≡≡ C-]2, 8(m), (m = 1, 3) by Eglinto...  相似文献   

3.
Small change in chemical structure of discotic liquid crystals can cause big difference in their mesomorphism. Replacing of the alkoxy peripheral chains of triphenylene by oxygen-atom containing ester chains would result in novel mesomorphism. A series of mixed tail triphenylenes containing propoxyacetyloxy and alkoxy, abbreviated as C18H6(OCnH2n+1)3(OCOCH2OC3H7)3, n=4-8, and hexa(propyloxyacetyloxy)triphenylene, C18H6(OCOCH2OC3H7)6 were synthesized. Thermal gravimetry analysis (TGA) of three discogens showed that they had good thermal stability till 350 ℃. The mesomorphism was investigated through differential scanning calorimetry (DSC) and polarized optical microscopy (POM). The preliminary X-ray diffraction (XRD) results of one compound showed that it exhibited ordered hexagonal columnar (Colho) mesophase. These mixed tail triphenylene derivatives possessed much stable Colho mesophase and wider mesophase ranges than their hexaalkoxytriphenylene C18H6(OR)6 and hexaalkanoyloxytriphenylene C18H6(OCOR')6 analogues. The asymmetrical compounds 2,6,11-trialkoxy-3,7,10-tri(2-propyloxyacetyloxy)triphenylenes with n=5-8 displayed higher clearing points and wider temperature ranges than their symmetrical isomers 2,6,10-trialkoxy-3,7,11-tri(2-propyloxyacetyloxy)- triphenylenes, while C18H6(OCOCH2OC3H7)6 had the highest clearing point due to the β-oxygen-atom effect.  相似文献   

4.
New symmetrical and asymmetrical triphenylene-containing discotic liquid crystals with two different peripheral alkyl chains, known as sym-TP(OC6H13)3(OR)3 and asym-TP(OC6H13)3(OR)3, were synthesized. Their thermotropic liquid crystal properties were investigated through polarizing optical microscopy (POM), differential scanning calorimetry (DSC) and X-ray diffraction (XRD) analyses. The asyrranetdcal discogens are 2,6,11-rialkoxy-3,7,10-trihexyloxytriphenylenes, with the alkyl chain carbon numbers varying from 3-10, 12, and 14, while the symmetrical compounds are 2,6,10-trialkyloxy-3,7,11-trihexyloxytriphenylene. Two fluoroalkoxy substituted triphenylene discogens, 2,6,10-td(4,4,4-trifluorobutoxy)-3,7,11-trihexyloxytriphenylene and its asymmetrical isomer 2,6,11-tri(4,4,4-trifluorobutoxy)-3,7,10-trihexyloxytdphenylene were prepared. These two compounds show higher melting and clearing points than their alkoxy analogs, which implies that fluorophilic effect exists in the formation and stabilization of discotic columnar mesophase. The triphenylene derivatives TP(OC6H13)3(OR)3 with two different peripheral chains, symmetrically or asymmetrically attached on triphenylene cores, have lower melting points and clearing points than those of the higher symmetrical compounds TP(OR)6 with the same total chain carbon numbers. The mixed-chain-triphenylenes with longer alkoxy chains (n=9,10,12,14) show columnarmesophase at room temperature.  相似文献   

5.
丁涪江  赵可清 《化学学报》2007,65(15):1454-1458
我们最近的实验显示: 对于分子中含有酰胺基的苯并菲液晶化合物C18H6(OC5H11)3(OCH2CONHC4H9)3, 对称化合物有比反对称异构体更高的清亮点和更有序的六方柱状介晶相, 且与具有同样软链长度的分子中不含酰胺基的化合物C18H6(OC5H11)3(OCH2COOC4H9)3相比较, 有更高的清亮点和更丰富的柱状介晶相. 本文通过量子化学ONIOM (B3LYP/6-31G(d,p):UFF)计算, 说明对于带酰胺基的分子, 对称分子比反对称分子有较大的稳定化能和较高的转动势垒. 对于对称性分子, 带酰胺基的分子比带酯基的分子有较大的稳定化能和较高的转动势垒. 这说明由酰胺基形成的分子间氢键起了稳定液晶相和锚定六方柱状相的作用, 可以解释带酰胺基的分子和对称性分子有较高的清亮点和更有序的六方柱状介晶相. 如果加长酰胺基的软链, 则可使氢键锚定的扭转角减少, 这样有利于提高电荷传输速率.  相似文献   

6.
陈红梅  赵可清  胡平  汪必琴 《化学学报》2007,65(14):1368-1376
全氟烃链的憎氟效应(fluorophobic effect)可有效地促使棒状分子形成近晶相, 并稳定液晶相. 为进一步探讨氟效应对盘状分子介晶性的影响, 合成了一系列全氟酯链的苯并菲化合物C18H6(OCnH2n+1)5(OCOC2H4C6F13) (a), 以及另一系列相对应的不含氟化合物C18H6(OCnH2n+1)5(OCOC8H17) (b), n=4~9. DSC检测和偏光显微镜观察显示两类化合物都为柱状相热致型液晶. 化合物a与相对应的化合物b比较, 其熔点和清亮点上升, 柱状相的热稳定性增强.  相似文献   

7.
The fluorophobic effect of the semi-fluorinated chain of discotic molecules efficiently improves the stability of columnar mesophase.Low symmetric discogens exhibit decreased melting points and wide mesophase ranges.A series of triphenylene derivatives 1,C18H6(OCnH2n+1)4(OMe)(O2CC2H4C6F13),and their hydrocarbon analogues 2,C18H6(OCnH2n+1)4(OMe)(O2CC8H17),n = 4―8,were synthesized for the investigation of the influence of semi-fluorinated peripheral chain and molecular symmetry on mesomorphism.The structures ...  相似文献   

8.
Excess molar volumes VmE for binary liquid mixtures of n-alkoxyethanols or polyethers + 2-pyrrolidinone or N-methyl-2-pyrrolidinone have been measured with a continuous dilution dilatometer at 298.15 K and atmospheric pressure as a function of composition. The alkoxyethanols are diethylene glycol monomethylether, 2-(2-methoxyethoxy) ethanol, CH3(OC2H4)2OH; diethylene glycol monoethylether, 2-(2-ethoxyethoxy) ethanol, C2H5(OC2H4)2OH; and diethylene glycol monobutylether, 2-(2-butoxyethoxy) ethanol, C4H9(OC2H4)2OH; whereas the polyethers are diethylene glycol dimethylether, bis(2-methoxyethyl)ether, CH3(OC2H4)2OCH3; diethylene glycol diethylether, bis(2-ethoxyethyl)ether, C2H5(OC2H4)2OC2H5; and diethylene glycol dibutylether, bis(2-butoxyethyl)ether, C4H9(OC2H4)2OC4H9. In all mixtures the excess molar volumes are negative and symmetric across the entire composition range. The excess volumes are fitted to the Redlich–Kister polynomial equation to obtain the binary coefficients and the standard errors. The experimental results have also been discussed on the basis of IR measurements.  相似文献   

9.
The disproportionation reaction of diaryl ditellurides [(C6H5Te)2, (p-CH3C6H4Te)2, (p-CH3OC6H4Te)2, (p-C2H5OC4Te)2, (2-naphthyl-Te)2] with sodium hydroxide under phase transfer conditions at room temperature is described for the first time. The phase transfer catalyst used is 2HT-75, a trade name for a mixture of dialkyldimethylammonium chlorides. The intermediates aryl tellurolates react “in situ” with alkyl halides to give the corresponding alkyl aryl tellurides (ArTeR) in 52–72% yield. The following compounds were prepared: Ar  C6H5, R=CH3(CH2)3CH2, (CH3)2CHCH2CH2, (CH3)2CHCH2, CH3CHBrCH2CH2, CH3(CH2)8CH2, C6H5CH2, ClCH2, C6H5CH2CH2, CH2CHCH2, C6H5CHCHCH2, C6H5SeCH2, CH2CH2CH2CHCHCH; Ar=p-CH3C6H4, R = CH3(CH2)2CH2; Ar=p-CH3OC6H4, R = CH3(CH2)2CH2; Ar = p-CH2H5OC6H4, R= CH3(CH2)2CH2; Ar = 2-naphthyl, R = CH3(CH42)2CH2.  相似文献   

10.
The Reaction of Molybdenum with 2,3-Dihydroxynaphthalene   总被引:1,自引:0,他引:1  
[H2N(CH2)3NH312[MoO2(C10H6O2)2] (1) was synthesized by the 2,3-dihydroxynaphthalene in the mixed solvent of CH3OH, CH3CN reaction of (n-Bu4N)4[Mo8O26] with and 1,3-propanediarnine. (C5HllN2)2- [HeN(CH2)3NH2][MoO2(CloH6O2)2] (2) was obtained by the reaction of Na2MoO4.2H20 with 2,3-dihydroxynaphthalene in the same solvent above. Both of the complexes possess complex anion [Mo(VI)O2(OC10H6O)2]^2- which shows pseudo-octahedrally coordinated fashion, while the counterions are two protonated 1,3-propanediamine in complex 1 and (CsH11N2)^+ in complex 2. (C5H11N2)+ is the byproduct of reaction 2, which results from combination of acetonitrile with 1,3-propanediamine. Packing diagrams of the two complexes are also different. There is anti-parallel-aligned-double-meso-bilayer unit in complex 1. However there are four chiral anions arranged in anticlockwise orientation in complex 2.  相似文献   

11.
The consecutive reactions of (CH3)2Si(OC2H5)2 and CH3Si(OC2H5)3 with methoxide ions were investigated in methanol solutions. The reverse transesterification reactions with ethoxide ions could be neglected in both cases since the concentration of ethoxide in methanol solution was assumed to be low due to the fast equilibrium reaction C2H5O? + CH3OH ? C2H5OH + CH3O?. The progress of the reactions was followed by monitoring the formation of ethanol with a Fourier-transform infrared spectrometer. All rate constants were determined at 295 K. The reactions between the dialkoxydimethylsilanes and methoxide ions were assumed to consist of two consecutive steps that can be represented by the net reaction; (CH3)2Si(OC2H5)2 + 2CH3O? → (CH3)2Si(OCH3)2 + 2C2H5O?. The two consecutive rate constants were established as 1.93 ± 0.12M?1s?1 and 1.00 ± 0.12M?1s?1, respectively. The consecutive rate constants for the reactions between the trialkoxymethylsilanes and methoxide ions can be written according to the total reaction; CH3Si(OC2H5)3 + 3CH3O? → CH3Si(OCH3)3 + 3C2H5O?. The three rate constants corresponding to each consecutive step were established as 1.12 ± 0.09 M?1s?1, 0.82 ± 0.10 M?1s?1, and 0.51 ± 0.06 M?1s?1, respectively. © 1995 John Wiley & Sons, Inc.  相似文献   

12.
赵可清  高彩艳  胡平  汪必琴  李权 《化学学报》2006,64(10):1051-1062
合成了三个系列, 共二十四个有两种不同软链的对称和非对称苯并菲盘状液晶化合物, C18H6(OR)3- (OCH2COOEt)3, C18H6(OR)3(OCH2COOBu)3, C18H6(OR)3(OCH2CONHBu)3, 其中R=C5H11, C6H13, C7H15, C8H17. 化合物通过柱层析纯化, 结构通过1H NMR, IR, 元素分析等确证. 化合物热稳定性通过TGA测定, 并显示出较高的热稳定性. 通过偏光显微镜和差视扫描量热法对这些化合物的热致液晶性进行了研究. 结果显示: 对于苯并菲液晶化合物C18H6(OR)3(OCH2COOEt)3, 非对称性化合物较之对称异构体化合物有更低的熔点和更高的清亮点, 因而非对称性化合物有更宽的介晶温度范围. 对于分子中含有酰胺基的苯并菲液晶化合物C18H6(OR)3(OCH2CONHBu)3, 对称化合物有比非对称异构体更高的清亮点和更有序的六方柱状介晶相, 且其与具有同样软链长度的分子中不含酰胺基的化合物系列C18H6(OR)3(OCH2COOBu)3相比较, 由于柱内分子间氢键的形成, 不仅有更高的熔点和清亮点, 而且有更丰富的柱状介晶相.  相似文献   

13.
The first γ-trimethylstannyl sulfimide, Me3Sn(CH2)3S(=NSO2Ar)C5H11-n, was synthesized by oxidative imination of Me3Sn(CH2)3SC5H11-n with ArSO2(Na)Cl (Ar=C6H4Cl-4). Oxidation of γ-trimethylstannyl sulfimide by an alkaline solution of H2O2 gave γ-trimethylstannyl sulfoximide, Me3Sn(CH2)3S(O)(=NSO2Ar)C5H11-n, and γ-trimethylstannyl sulfone, Me3Sn(CH2)3SO2C5H11-n, the latter compound resulting from hydrolysis of the arylsulfimide group. Oxidation of stannyl sulfide by hydrogen peroxide yielded γ-trimethylstannyl sulfoxide, Me3Sn(CH2)3S(O)C5H11-n (under mild conditions) or γ-trimethylstannyl sulfone (under more severe conditions). Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 371–374, February, 1997.  相似文献   

14.
余文浩  赵可清  汪必琴  胡平 《化学学报》2007,65(12):1140-1148
盘状液晶分子能自组装成高度有序的六方柱状介晶相. 其各向异性的载流子高速迁移率使其成为较理想的有机光电子材料. 采用分子间氢键锚定柱状相, 获得介晶相温度范围宽、有序度高的苯并菲盘状液晶是本研究的目的. 本文通过分子设计, 合成了3个系列, 共18个有两种不同软链的苯并菲盘状液晶化合物C18H6(OR)5(OCH2COOEt), C18H6(OR)5(OCH2COOBu)和C18H6(OR)5(OCH2CONHBu), 其中R=CnH2n+1, n=4~9. 化合物的纯度和结构通过1H NMR和元素分析确证. 化合物热稳定性通过热重分析(TGA)测定, 并显示出较高的热稳定性. 通过偏光显微镜(POM)和差示扫描量热法(DSC)对这些化合物的热致液晶性进行了研究. 结果显示对于分子中含有酰胺基的苯并菲液晶化合物C18H6(OR)5(OCH2CONHBu), 与具有同样软链长度的分子中不含酰胺键的化合物系列C18H6(OR)5(OCH2COOBu)相比较, 前者由于柱内分子间氢键的形成, 具有更高的熔点和清亮点.  相似文献   

15.
苯丙炔酸和苯丙烯酸酯苯并菲盘状液晶的合成及介晶性   总被引:2,自引:0,他引:2  
合成了7个含苯丙炔酸和苯丙烯酸酯链的苯并菲盘状液晶化合物C18H6(OCnH2n+1)5O2CR' [R'=C≡CC6H5, n=4~9 (1a1f); R'=CH=CHC6H5, n=6 (1g)]. 该系列化合物结构通过1H NMR, IR和元素分析表征. 液晶性通过差示扫描量热法和偏光显微镜进行了研究, 结果显示: 化合物均为六方柱状相热致型液晶; 含苯丙炔酸酯链苯并菲盘状液晶化合物1a1f, 随着烷氧链的增长, 清亮点呈现逐渐下降的趋势; 对于含苯丙烯酸酯链苯并菲化合物1g与具有同样软链长度的炔基酯链苯并菲化合物1c比较, 具有更低的熔点和结晶点, 而它们的清亮点几乎一致, 因而化合物1g有更宽的介晶性温度范围.  相似文献   

16.
RAMAN and IR spectroscopic investigation of alkyl derivatives of arsenic acid. II. Vibrational spectra of some alkanearsonic acid dialkylesters RAMAN and IR spectra of CH3AsO(OCH3)2, CH3AsO(OC2H5)2, C2H5AsO(OCH3)2, and C2H5AsO(OC2H5)2, are communicated and discussed. Their skeleton CAsO(OC)2 has very probably Cs symmetry.  相似文献   

17.
The title compound, [Cu3(C3H5O2)6(C6H7NO)4]n, is composed of polymeric chains formed by alternating centrosymmetric Cu2(μ‐CH3CH2CO2)4 and Cu(C3H5O2)2(C6H7NO)2 units. These elemental units are linked by two bridging 3‐pyridylmethanol (3PM) ligands. The Cu2(μ‐CH3CH2CO2)4 group presents a centrosymmetric tetra­bridged structure with four synsyn bridging propionate ligands to which two 3PM mol­ecules are bonded (through N), occupying the apical positions of each square‐pyramidal polyhedron around the CuII ions. The remaining mononuclear group is centred around a third CuII ion, which lies on a symmetry centre and is bound to two monodentate propionate groups (through O), two monodentate 3PM mol­ecules (through N) and two bridging 3PM mol­ecules (through O), thus completing a square‐bipyramidal CuO2N2O2 coordination.  相似文献   

18.
Chiral C5H5(C9H7Ti(Cl)SCH(CH3)2 shows diastereotopic CH3 resonances; the diasteroisomers of C5H5(CH3C5H4Ti(Cl)OC10H19 could be separated by fractional crystallisation.  相似文献   

19.
Synthetic routes for the preparation of 3-alkyl-6-phenyl-4(3H)-pteridinones 6 and their corresponding 8-oxides 5 (R = CH3, C2H5, (CH2)2CH3, (CH2)3CH3, CH(CH3)C2H5, CH(CH3)2 and CH(C2H5)CH2OCH(OC2H5)2 are described and their reactivities towards xanthine oxidase from Arthrobacter M-4 are determined. Only the 3-methyl derivative of 6-phenyl-4(3H)-pteridinone and its 8-oxide i. e. 6a and 5a are found to be substrates although their reactivities are still very low. Oxidation takes place at C-2 of the pteridinone nucleus. All the 3-alkyl derivatives are less tightly bound to the enzyme than 6-phenyl-4(3H)-pteridinone. Introduction of the N-oxide at N-8 considerably lowers the binding of the substrates. Inhibition studies have revealed that 3-methyl-6-phenyl-4(3H)-pteridinone ( 6a ) is a non-competitive inhibitor with a Ki-value of 47 μM and the 3-ethyl derivative ( 6b ) an uncompetitive one with a Ki-value of 19.6 μM.  相似文献   

20.
We report metathetical reactions of IF5 with series of α,β-trimethylsilylated ethanediolates with increasing numbers of CH3-groups in α- and β-positions. Short lived intermediates IF4[OC2H4?n(CH3)nO]X with X = Si(CH3)3 or IF4 and stable chelates IF3[OC2H4?n(CH3)nO] and IF[OC2H4?n(CH3)nO]2 (n = 0–4) are observed and characterized. Time and temperature dependence of 19F-NMR-spectra in relation to degree of methylation, arrangement and stereo-chemistry are discussed referring to previously published mono- and polynuclear I(V)-compounds containing a series of monodentate alcoholates CH3?n(CH3)nO? and (CH3)3CCH2O? (n = 0,2,3) [1,2] and of bidentate alcoholates ?O(CH2)nO? (n = 2,3,4,5,6,12) [1]. In contrast to aliphatic α,β-diolates the aromatic diolates 1,2-C6H4(O?)2, 1,2-C6Cl4(O?)2 rapidly undergo redox reactions even at low temperatures.  相似文献   

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