共查询到20条相似文献,搜索用时 15 毫秒
1.
Jun-Woo Lee Xiang Lin Piao Yong-Kuk Yun Yoon-Sok Kang Wang-Cheol Zin 《Liquid crystals》2013,40(11):1671-1685
Two series of new dimesogenic liquid crystalline compounds were synthesized and their LC and other thermal properties were characterized. These compounds consist of two mesogenic units connected through polymethylene spacer of varying length in the shape of the letter ‘T’. The difference between the two series is in the structure of tail groups attached on the pendant azobenzene mesogens; one of which is n-butyl and the other is phenyl. The compounds were characterized for their liquid crystallinity by the differential scanning calorimetry (DSC), X-ray diffractometry and visual observation of the melts on a hot-stage attached to a polarizing microscope. All these compounds were found to form only the nematic phase enantiotropically. 相似文献
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Adil A. Al-Fregi Bushra K. Al-Salami Zainab K. Al-Khazragie 《Phosphorus, sulfur, and silicon and the related elements》2019,194(1-2):33-38
A series of tellurated azo compounds [i.e. (4-HOC6H4N=N-Ar)TeBr3 and (4-HOC6H4N=N-Ar)2TeBr2, where Ar=5-BrC6H3, 5-CH3C6H3 and 5-NO2C6H3] were prepared by the reaction of the corresponding 2-(4-hydroxyphenylazo)aryl mercury chloride with tellurium tetrabromide in 1:1 and 2:1?mole ratio, respectively in dry dioxane as a solvent. The reduction of (4-HOC6H4N=N-Ar)TeBr3 by hydrazine hydrate gave the corresponding ditelluride (i.e., (4-HOC6H4N=N-Ar)2Te2). Treatment of (4-HOC6H4N=N-Ar)2TeBr2 with hydrazine hydrate afforded the corresponding tellurides, (4-HOC6H4N=N-Ar)2Te), in good yields. The structures of all newly synthesized compounds were assigned on the basis of their elemental and spectroscopic data. The antibacterial activity of tellurated azo compounds along with mercurated azo compounds was tested with agar diffusion method against the bacteria strains Staphylococcus aureus and Escherichia coli. The antibacterial activities of tellurated azo compounds were in some cases equal or better than those of the reference drug. The mercurated azo compounds were found to be the more antibacterial activity of than those of tellurated azo compounds. 相似文献
3.
Gönül Yenilmez Çiftçi Esra Tanrıverdi Eçik Tuba Yıldırım Kemal Bilgin Elif Şenkuytu Fatma Yuksel Yıldız Uludağ Adem Kılıç 《Tetrahedron》2013,69(5):1454-1461
In the present study, spiro (1a), dispiro (1b, 2, 3), per-substituted spermine-bridged (6–9) and dispiroansa spermine (10) derivatives of cyclotriphosphazene have been synthesized. The structures of the novel compounds (1b, 6–10) have been characterized by elemental analysis, FTIR, mass spectrometry, 1H and 31P NMR spectroscopy. The molecular structures of 1b, 2, 8, and 10 were determined by single crystal X-ray crystallography. In order to investigate the anti-tumour properties of the newly synthesized cyclotriphosphazene derivatives, in vitro cytotoxic activity test (MTT assay) has been performed using HT-29 (human colon adenocarcinoma) and Hep2 (human epidermoid larynx carcinoma) cell lines. The result of the MTT assay showed that while compound 1a has cytotoxic effect on both Hep2 and HT-29 cell lines, compound 3 has only cytotoxic effect towards the Hep 2 cells. 相似文献
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Synthesis and liquid crystalline properties of a series of cholesterol-based dimesogenic compounds 总被引:1,自引:0,他引:1
《Liquid crystals》2007,34(3):283-288
The synthesis and mesomorphic properties of a series of novel dimesogenic compounds containing the cholesteryl ester unit and a phenyl benzoate group are reported. The two mesogenic units of these compounds are linked through dicarboxylic ester bonds, with alkylene spacer lengths of 2, 4, 6 and 8 methylene units. The chemical structures and liquid crystalline properties of this series of compounds were characterized by FTIR, 1H NMR, hot stage-coupled polarizing microscopy and DSC. The results show that this series of compounds are cholesteric liquid crystals over a wide range, both during heating and cooling, and they exhibit iridescent colours in the liquid crystalline state. 相似文献
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Ali Z. Al‐Rubaie Wasfi A. Al‐Masoudi Shaker A. N. Al‐Jadaan Abraham F. Jalbout Ali Jameel Hameed 《Heteroatom Chemistry》2008,19(3):307-315
The reaction of ortho‐mercurated anilines with benzaldehyde gave the ortho‐mercurated Schiff bases. The reaction of the mercurated Schiff bases with tellurium tetrabromide in 1:1 and 2:1 mole ratio using dry chloroform as solvent gave the ortho‐tellurated Schiff bases compounds ArTeBr3 and Ar2TeBr2, respectively, in good yields (where Ar = 5‐ClC6H3N=CHC6H5, 5‐BrC6H3N=CHC6H5, 5‐CH3OC6H3N=CHC6H5, and 5‐NO2C6H3N=CHC6H5). The reduction of ArTeBr3 by hydrazine hydrate gave the corresponding ditelluride (i.e., Ar2Te2). Treatment of Ar2TeBr2 with hydrazine hydrate afforded tellurides (Ar2Te) in good yields. Attempts to prepare the corresponding aryl tellurenyl bromides, ArTeBr, by partial reduction of ArTeBr3 with various reducing agents were unsuccessful. All these new compounds were characterized by microanalysis, 1H, and 13C NMR, IR, and mass spectroscopic data. A computational study for the Te → N interactions of all compounds was calculated using the GAUSSIAN 03 program package. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:307–315, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20437 相似文献
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B. M. Baysal W. T. Short A. V. Tobolsky 《Journal of polymer science. Part A, Polymer chemistry》1972,10(3):909-919
The synthesis and characterization of several polymeric peroxycarbamates prepared by successive reaction of poly(ethylene oxides), first, with diisocyanates, and then with hydroperoxides, are described in detail for bis(2,5-dimethyl-2-hydroperoxyhexane peroxycarbamate) polyethers, the chain-extended analogs of these peroxycarbamyl polyethers and for bis(α-cumyl peroxycarbamate) polyether. The polymerization of styrene with this last initiator was studied at 60, 80, and 100°C. Both low- and high-conversion polymerizations were studied. The relationship between the rates of initiation and the inverse degree of polymerization was determined. 相似文献
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A.J. De Koning P.E. Van Rijn J. Boersma G.J.M. van der Kerk 《Journal of organometallic chemistry》1979,174(2):129-140
Ethyl (ω-dimethylamino-1 -alkynyl)zinc compounds and bis (ω-dimethylamino-l-alkynyl)zinc compounds were prepared by metalation of the dimethyl amino alkynes HCC(CH2)n,NMe2 (n = 1–4) with diethylzinc and diphenylzinc. All compounds show oligomeric or polymeric association in benzene, the degree of association being dependent on the value of n. The presence of coordinating dimethylamino groups and/or bridging alkynyl groups was established by IR and NMR spectroscopy. Plausible structures for all compounds, based on spectroscopic and molecular weight data, are presented. 相似文献
10.
Chang‐Cheng Wu 《Liquid crystals》2013,40(3):283-288
The synthesis and mesomorphic properties of a series of novel dimesogenic compounds containing the cholesteryl ester unit and a phenyl benzoate group are reported. The two mesogenic units of these compounds are linked through dicarboxylic ester bonds, with alkylene spacer lengths of 2, 4, 6 and 8 methylene units. The chemical structures and liquid crystalline properties of this series of compounds were characterized by FTIR, 1H NMR, hot stage‐coupled polarizing microscopy and DSC. The results show that this series of compounds are cholesteric liquid crystals over a wide range, both during heating and cooling, and they exhibit iridescent colours in the liquid crystalline state. 相似文献
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Seven Schiff base polymers poly 5,5′-methylenebis(2-hydroxyacetophenone)semicarbazone (PHASC), poly-5,5′-methylenebis(2-hydroxyacetophenone)thiosemicarbazone (PHATS), poly 6,6′-methylenebis(2-hydroxynaphthaldehyde)1,2-propylenediimine (PHNPn), poly 6,6′-methylenebis (2-hydroxynaphthaldehyde)1,3-propylenediimine (PHNPR), poly 6,6′-methylenebis (2-hydroxy-naphthaldehyde)thiosemicarbazone (PHNTS), poly 6,6′-methylenebis(2-hydroxy-naphthaldehyde)urea (PHNU) and poly-6,6′-methylenebis(2-hydroxynaphthaldehyde)semicarbazone (PHNSC) were prepared by polycondensation of 5,5′-methylenebis(2-hydroxyacetophenone) (MHA) or 6,6′-methylenebis(2-hydroxynaphthaldehyde) (MHN) with semicarbazide, thiosemicarbazide, 1,2-propylenediamine, 1,3-propylenediamine or urea. The polymers were characterized by elemental micro-analysis, infrared and ultraviolet spectroscopy and viscosity measurements. The reduced viscosity of the polymers measured in dimethylformamide (DMF) was observed in the range 0.32-0.63 dl/g. 相似文献
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Ülkü Yılmaz Hasan Küçükbay 《Phosphorus, sulfur, and silicon and the related elements》2020,195(7):580-585
AbstractN-heterocyclic carbene (compound b) was synthesized from reaction of 1-(3-phenylpropyl)-3-methylbenzimidazolium iodide (a) and a strong base in an argon atmosphere. Then, 1-(3-phenylpropyl)-3-methylbenzimidazolium-2-carbodithioate (c) was prepared with carbene and CS2. Finally, a group of alkyl 1-(3-phenylpropyl)-3-methylbenzimidazolium-2-carbodithioate halides was synthesized with alkyl halides and compound c, occurring products 1-6. Structural characterization of compounds was performed 1H, and 13C NMR, IR, and MS spectroscopy and elemental analysis. 相似文献
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Synthesis and polycondensation of some new organotellurium compounds containing hydroxymethyl groups
A new series of organotellurium compounds [i.e. 2‐HOCH2C6H4TeBr3 (1), (2‐HOCH2C6H4)2TeBr2 (2), (2‐HOCH2C6H4)2Te (3), (2‐HOCH2C6H4Te? )2 (4), 4‐HOCH2C6H4TeBr3 (5), (4‐HOCH2C6H4)2TeBr2 (6), (4‐HOCH2C6H4)2Te (7), and (4‐HOCH2C6H4Te? )2 (8)] were prepared by reacting hydroxymethylphenylmercury chlorides with tellurium tetrabromide in dry dioxane. Bis(2‐hydroxymethylphenyl) telluride (3), bis(2‐hydroxymethylphenyl) ditelluride (4) and bis(4‐hydroxymethylphenyl) telluride (7) were polymerized by a solution polycondensation technique with toluene diisocyanate and terephthaloyl chloride, leading to new organic tellurium polyurethanes and polyesters. All the new compounds were characterized by elemental analysis and spectroscopic data. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
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将含过氧铌一、三取代钨硅、钨磷过氧杂多阴离子利用离子交换法嵌入Zn2Al类水滑石中制得层柱化合物,利用XRD,IR,UV等方法对产物的结构进行了表征。结果表明在层柱化合物中过氧杂多阴离子仍然保持Keggin结构,并且过氧键没被破坏。层柱化合物在酯化反应中显示优良的催化性能。 相似文献
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Marta Worzakowska 《Journal of Thermal Analysis and Calorimetry》2014,116(2):727-736
Synthesis, characterization, and thermal properties of new, flavor, long chain esters were presented. The new compounds were obtained in the catalytic esterification process of a stoichiometric ratio of trans-3,7-dimethyl-2,6-octadien-1-ol, succinic anhydride, and aliphatic chain diol. As diols ethylene glycol, 1,4-buthylene glycol, 1,5-pentylene glycol, and 1,6-hexylene glycol were applied. The spectroscopic analyses completely confirmed that the applied synthesis conditions allowed obtaining the new compounds with high yield and purity. Their thermal properties were studied in inert and oxidative atmospheres. The esters were less thermally stable in inert (IDT 186–195 °C) than in oxidative (IDT 210–228 °C) atmosphere. Two, non-completely divided decomposition steps were visible during their pyrolysis. In contrast, the new, long chain compounds decompose in three major steps in air. The analyses of the volatile products emitted during their pyrolysis indicated on the asymmetrical disrupt of their bonds. The formation of acyclic and alicyclic monoterpene hydrocarbons, succinic anhydride, diols, alcohols, alkenes, and water was observed. It indicated mainly on the β-elimination reactions during their pyrolysis. Also, β-elimination reactions of esters are mainly expected in air. Initially, it resulted in the formation of acyclic and alicyclic monoterpene hydrocarbons, hydroxyl compounds (diols, alcohols), and its β-elimination products: aldehydes, alkenes, and water. However, the presence of oxygen in the medium causes the partial decarboxylation and oxygenation of aldehydes and thus the formation of alkenes and carbon dioxide. In addition, the beginning of evaporation of succinic anhydride was detected at T max1. At T max2 the evaporation of succinic anhydride, their partial decarboxylation to CO2, the small amounts of diols, alcohols, and aldehyde fragments were indicated. Finally, succinic anhydride, water, and carbon dioxide were only observed during decomposition of studied esters in air. 相似文献
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Werner Löwe Stefanie Brätter Christoph Dietrich Manuela Weber Peter Luger 《Journal of heterocyclic chemistry》1997,34(4):1173-1178
We report here the syntheses and characterization of new crown-type compounds 8 and 9 incorporated with one and two 4-pyrone units. The reaction of compound 3 with 1,5-bis(2-hydroxyphenoxy)-3-oxapentane or catechol gave the desired molecules 8 and 9 in 65% and 25% yields, respectively. Compound 3 resulted from 1 by Wohl-Ziegler bromination in small amounts and could be separated from five bromination by-products by column chromatography. For example, 8 binds K+ and a pyrylium salt 11 (single crystal X-ray structure analysis) can also be prepared starting from 3 by treatment of the latter with perchloric acid in the presence of acetonitrile. 相似文献
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A new series of organotellurium(IV) compounds based on di(cyclohexylmethyl)telluride ( 1 ) (i.e., (C6H11CH2)2TeX2 and (C6H11CH2)2Te(R)X) was prepared by the reaction of compound 1 with halogens, N‐bromosuccinimide, and alkyl halides. Phenylation of (C6H11CH2)2TeX2 with sodium tetraphenylborate gave di(cyclohexylmethyl)phenyltelluronium tetraphenylborate in good yield. Conductivity measurements in dimethylsulfoxide (DMSO) showed a considerable ionic character of these compounds and they behave as 1:1 electrolytes. 1H NMR studies in CDCl3 solution indicated that telluronium salts employed in this study are unstable toward reductive elimination. Reaction of di(cyclohexylmethyl)telluride, (C6H11CH2)2Te(CH3)I, and (C6H11CH2)2Te(PhCH2)Br with HgX2 (X = Cl or Br) afforded 1:1 complexes. All compounds were characterized by elemental analyses and spectroscopic data. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:93–99, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20240 相似文献
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《Journal of Coordination Chemistry》2012,65(20):3336-3349
Complexes of Cu(II), Fe(II) and Fe(III) have been synthesized with 2-nitro-3,3′-benzylidene bis[4-hydroxycoumarin]/4-chloro-3,3′-benzylidene bis[4-hydroxycoumarin]/4-hydroxy-3,3′-benzylidene bis[4-hydroxycoumarin]. They have been characterized using 1H-NMR, 13C-NMR, IR spectra, electronic spectra, magnetic measurements, elemental analyses and screened for their in-vitro biocidal activity against Bacillus cereus, Staphylococcus aureus, Escherichia coli, Bacillus subtilis, Salmonella typhi, and Serratia marcescens bacterial strains and for their in-vitro antifungal activity against Aspergillus niger, Aspergillus flavus and Lasiodiplodia theobromae. The metal complexes exhibit good activity against bacterial strains compared to parent compounds, but no significant antifungal activity against fungal strains. In-vitro nuclease activity has been carried out using agarose gel electrophoresis. The synthesized compounds show effective nuclease activity. 相似文献