- Synthesis and Liquid Crystal Properties of Supramolecular Side-Chain Liquid-Crystalline Polymers Containing Poly(acrylic acid) Intermolecular Hydrogen Bonds
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Novel supramolecular side-chain liquid-crystalline polymers were prepared from poly(acrylic acid) (PAA) and pyridyl Schiff base derivatives through intermolecular hydrogen-bonding interaction between PAA and nitrogen of pyridyl Schiff base derivatives. PAA used as H-bond donor. Pyridyl Schiff base derivatives used as H-bond acceptors. The existence of H-bonding was confirmed by FT-IR spectroscopy. Polymer complexes exhibited stable thermotropic mesophase. Differential scanning calorimetry, polarized optical microscopy, and X-ray diffraction measurements were used to investigate LC behavior. The complexes exhibited smectic C phase broken-fan shaped texture. On increasing spacer length of substituent, the clearing temperature range of the mesophase increased.
- Kandasamy,Keerthiga,Vijayalakshmi,Kaliyappan
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Read Online
- Oxalic Diamides and tert-Butoxide: Two Types of Ligands Enabling Practical Access to Alkyl Aryl Ethers via Cu-Catalyzed Coupling Reaction
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A robust and practical protocol for preparing alkyl aryl ethers has been developed, which relies on using two types of ligands to promote Cu-catalyzed alkoxylation of (hetero)aryl halides. The reaction scope is very general for a variety of coupling partners, particularly for challenging secondary alcohols and (hetero)aryl chlorides. In case of coupling with aryl chlorides and bromides, two oxalic diamides serve as the powerful ligands. The tert-butoxide is first demonstrated as a ligand for Cu-catalyzed coupling reaction, leading to alkoxylation of aryl iodides complete at room temperature. Additionally, a number of carbohydrate derivatives are applicable for this coupling reaction, affording the corresponding carbohydrate-aryl ethers in 29-98% yields.
- Chen, Zhixiang,Jiang, Yongwen,Zhang, Li,Guo, Yinlong,Ma, Dawei
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supporting information
p. 3541 - 3549
(2019/02/26)
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- Columnar self-assembly of bowl shaped fluorescent liquid crystals based on calix[4]arene with Schiff base units
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A new family of bowl-shaped molecules with a calix[4]arene rigid core and appended on four-sides, that display a wide range of hexagonal columnar phases, has been synthesised and well characterized. The thermal behaviours of the present compounds were established using a combination of polarising optical microscopy (POM), differential scanning calorimetry (DSC) and a high-temperature powder X-ray diffraction method (XRD). It is found that all of the synthesised materials show an enantiotropic hexagonal columnar liquid crystal phase. The structural and conformation characterization of these newly synthesised compounds was achieved by FT-IR, 1H NMR, and 13C NMR spectroscopy. All of the synthesised compounds exhibited good blue luminescence in solution under long wavelength UV light. To explore the structure property correlations, the alkoxy side chain group was varied from a lower alkyl spacer to a higher alkyl spacer on the lower rim of the calix[4]arene. The present research specified that the introduction of linking groups on the lower rim with an n-alkoxy side group is an influential approach to obtaining a supramolecular bowl shape liquid crystal which has good thermal and photophysical behaviour.
- Sharma, Anuj S.,Sharma, Vinay S.,Vekariya, Rajesh H.
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supporting information
p. 15044 - 15051
(2018/09/29)
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- Investigation of hydro-lipophilic properties of n-alkoxyphenylhydroxynaphthalenecarboxamides ?
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The evaluation of the lipophilic characteristics of biologically active agents is indispensable for the rational design of ADMET-tailored structure–activity models. N-Alkoxy-3-hydroxynaphthalene-2-carboxanilides, N-alkoxy-1-hydroxynaphthalene-2-carboxanilides, and N-alkoxy-2-hydroxynaphthalene-1-carboxanilides were recently reported as a series of compounds with antimycobacterial, antibacterial, and herbicidal activity. As it was found that the lipophilicity of these biologically active agents determines their activity, the hydro-lipophilic properties of all three series were investigated in this study. All 57 anilides were analyzed using the reversed-phase high-performance liquid chromatography method for the measurement of lipophilicity. The procedure was performed under isocratic conditions with methanol as an organic modifier in the mobile phase using an end-capped non-polar C18 stationary reversed-phase column. In the present study, a range of software lipophilicity predictors for the estimation of clogP values of a set of N-alkoxyphenylhydroxynaphthalenecarboxamides was employed and subsequently cross-compared with experimental parameters. Thus, the empirical values of lipophilicity (logk) and the distributive parameters (π) were compared with the corresponding in silico characteristics that were calculated using alternative methods for deducing the lipophilic features. To scrutinize (dis)similarities between the derivatives, a PCA procedure was applied to visualize the major differences in the performance of molecules with respect to their lipophilic profile, molecular weight, and violations of Lipinski’s Rule of Five.
- Kapustikova, Iva,Bak, Andrzej,Gonec, Tomas,Kos, Jiri,Kozik, Violetta,Jampilek, Josef
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- Synthesis and mesomorphic properties of 2,4-bis(4′-n-pentyloxybenzoyloxy)- benzylidine-4″- n-alkoxyaniline
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The synthesis and mesomorphic properties of a new series of 2,4-bis(4′-npentyloxybenzoyloxy)- benzylidine-4″ -n-alkoxyaniline (DC5An) are reported. The molecular structure of compounds was confirmed by FTIR, 1H-NMR, 13C-NMR, mass spectroscopy and elemental analysis. The mesomorphic properties were studied by differential scanning calorimetry (DSC) and polarizing optical microscopy (POM) measurements. All compounds of the series exhibit nematic (N) and smectic C (SmC) phases. The first four homologues (DC5A1-DC5A4) display a N mesophase, whereas the highest homologues (DC5A5-DC5A10) exhibit an enantiotropic dimorphism N and SmC phases. The mesomorphic properties of the present series are compared and discussed with other structurally related series.
- Hamad, Wali M.,Azeez, Hashim J.,Al-Dujaili, Ammar H.
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- Synthesis and antimicrobial studies of new antibacterial azo-compounds active against staphylococcus aureus and listeria monocytogenes
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Some novel (phenyl-diazenyl)phenols (4a–m) were designed and synthesized to be evaluated for their antibacterial activity. Starting from an active previously-synthesized azobenzene chosen as lead compound, we introduced some modifications and optimization of the structure, in order to improve solubility and drug conveyance. Structures of all newly-synthesized compounds were confirmed by 1H nuclear magnetic resonance (NMR), mass spectrometry, and UV-Vis spectroscopy. Antibacterial activity of the new compounds was tested with the dilution method against the bacteria strains Listeria monocytogenes, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa PAO1. All the compounds were selectively active against Gram-positive bacteria. In particular, compounds 4d, 4h, and 4i showed the highest activity against S. aureus and Listeria monocytogenes, reaching remarkable MIC100 values of 4 μg/mL and 8 μg/mL. The relationship between antimicrobial activity and compound structure has suggested that the presence of hydroxyl groups seems to be essential for antimicrobial activity of phenolic compounds.
- Piotto, Stefano,Concilio, Simona,Sessa, Lucia,Diana, Rosita,Torrens, Gabriel,Juan, Carlos,Caruso, Ugo,Iannelli, Pio
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- Dependence of LC state on molecular flexibility
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A novel azoester homologous series of liquid crystals (LCs) viz. RO?C6H4COOC10H6-N?N(ortho)-C6H4?OC4H9(para) has been synthesized and studied with a view to understanding and establishing the effect of molecular structure on LC properties. Homologous Series consists of thirteen members (C1 to C18). C1 to C3 members are nonliquid Crystals and the rest of the homologues are LC in an enantiotropic manner. C7 to C18 are smectogenic in addition to nematogenic whereas C4, C5, and C6 are only nematogenic. The Sm-N and N?I transition curves behave in a normal manner with the usual exhibition of an odd–even effect. The Cr-M/I curve also behaves in a normal manner. Analytical and spectral data confirm the molecular structures of homologues. The average smectic and nematic thermal stabilities are 60.31°C and 79.6°C, respectively, with total mesophase length varying minimum to maximum is 21°C to 57°C at the C6 and C14 homologue, respectively. Thus, present novel azoester homologous series is partly smectogenic and predominantly nematogenic with low ordered melting type and useful to construct LC devices workable at low temperatures or room temperature.
- Jadeja,Sharma, Vinay S.,Jain,Patel
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p. 144 - 153
(2016/07/14)
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- Study of mesomorphism dependence on molecular flexibility of an azoester series containing a napthyl unit
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A novel azoester homologous series of liquid crystalline (LC) compounds: RO?C6H4-COO?C10H6-N:N-C6H4?OC4H9(n) without lateral substitution has been synthesized and studied with a view to understanding and establishing the effects of molecular structure on thermotropic LC substances with reference to tailed-end group. The novel homologous series consists of 13 homologs (C1 to C18) whose nematogenic and smectogenic mesomorphism commences enantiotropically from C6 and C12 members of the series, respectively. The C12–C18 homologs are smectogenic and C6–C18 are nematogenic, of which C12–C18 homologs are smectogenic plus nematogenic. The C1–C5 homologs are nonmesogenic. Transition temperatures and the textures of the homologs were determined and identified by an optical polarizing microscope (POM) equipped with a heating stage. Textures of a nematic phase are threaded or Schlieren and that of the smectic phase are of the type A or C. Transition curves Cr-M/I, Sm-N and N-I of a phase diagram behaved in normal manner except N-I transition temperature of C10 homolog which deviated by 9°C–10°C from normal behavior. N-I transition curve exhibited odd-even effect. Analytical, spectral, and thermal data confirms the molecular structures of homologs. Thermal stability for smectic and nematic are 115.5°C and 138.5°C, respectively whose corresponding mesophaselengths are varied from 10.0°C to 16.0°C and 13.0°C to 24.0°C, respectively. Group efficiency order for smectic and nematic are derived from comparative study of structurally similar analogous series; as smectic: ?OC4H9 (n) > ?CH3 > ?H; Nematic: ?H > ?OC4H9 (n) > ?CH3
- Jadeja,Patel
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- The effect of molecular rigidity and flexibility on the mesomorphism of azoesters
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ASBTRACT: An Azoester novel homologous series RO-C6H4-COO-C6H4-N?N-C6H4-OC4H9(n) (para) of liquid crystalline (LC) materials are synthesized and studied with a view to understanding and establishing the effects of molecular structure on liquid crystal behavior with reference to lateral, terminal, or central group or groups on the basis of molecular rigidity and/or flexibility. The novel homologous series consists of thirteen (C1 to C18) homologues. C1 to C5 homologues are nonmesogenic and the rest of the homologues are enantiotropically mesogenic. C8 to C18 homologues are smectogenic plus nematogenic and the remaining two C6 and C7 homologues are only nematogenic without exhibition of smectic property. Analytical, thermal and spectral data confirms the molecular structures. Textures and transition temperatures of homologues were determined by an optical polarizing microscope (POM) equipped with a heating stage. Textures of a nematic phases are threaded or Schlieren and that of a smectic phase are of the type of A or C. The average thermal stabilities for smectic and nematic are 111.3°C and 124.7°C, respectively. The smectic and nematicmesophase lengths from 10.0°C to 28.0°C and 7.0°C to 16.0°C, respectively. The transition temperatures are compared with known series.
- Jadeja,Patel
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- Photoliquefiable ionic crystals: A phase crossover approach for photon energy storage materials with functional multiplicity
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Ionic crystals (ICs) of the azobenzene derivatives show photoinduced IC-ionic liquid (IL) phase transition (photoliquefaction) upon UV-irradiation, and the resulting cis-azobenzene ILs are reversibly photocrystallized by illumination with visible light. The photoliquefaction of ICs is accompanied by a significant increase in ionic conductivity at ambient temperature. The photoliquefaction also brings the azobenzene ICs further significance as photon energy storage materials. The cis-IL shows thermally induced crystallization to the trans-IC phase. This transition is accompanied by exothermic peaks with a total ΔH of 97.1 kJmol-1, which is almost double the conformational energy stored in cisazobenzene chromophores. Thus, the integration of photoresponsive ILs and self-assembly pushes the limit of solar thermal batteries.
- Ishiba, Keita,Morikawa, Masa-Aki,Chikara, Chie,Yamada, Teppei,Iwase, Katsunori,Kawakita, Mika,Kimizuka, Nobuo
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supporting information
p. 1532 - 1536
(2015/02/05)
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- AZOBENZENE COMPOUND AND HEAT PUMP SYSTEM USING THE SAME
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PROBLEM TO BE SOLVED: To provide an azobenzene compound capable of repeated structural changes without heating, and a heat pump system using the same. SOLUTION: An azobenzene compound represented by the general formula (1) and undergoing cis-trans isomerization reaction upon light irradiation is used as a heat medium of a heat pump system. In the formula, at least one of R1 to R3 is (CH2CH2O)n-R10; R4 is R11, O-R11, NH-R11, or COO-R11; X- is Cl-, Br-, I-, BF4-, PF6-, CH3(CH2)nSO3-, TsO-, (YSO2)2 N-, or (NC)2 N-; n is an integer between 0 and 2; and Y is F, CF3, or C2F5. COPYRIGHT: (C)2015,JPO&INPIT
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Paragraph 0074; 0075; 0076; 0077
(2016/10/10)
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- Synthesis and properties of 4-[(E)-(4'-R-phenyl)diazenyl]phthalonitriles and cobalt phthalocyanines obtained therefrom
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The diazotization-azocoupling method has been utilized to prepare a series of previously unknown 4-[(E)-(4'-R-phenyl)diazenyl]phthalonitriles, which were further transformed into the corresponding cobalt phthalocyanines. The effect of the peripheral substitution of the phthalocyanine ligand on the spectral properties of the prepared compounds has been demonstrated.
- Tikhomirova,Gruzdeva,Shaposhnikov
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p. 2778 - 2785
(2016/02/18)
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- Synthesis and Biological Evaluation of N-Alkoxyphenyl-3-hydroxynaphthalene-2-carboxanilides
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A series of fifteen new N-alkoxyphenylanilides of 3-hydroxynaphthalene-2-carboxylic acid was prepared and characterized. Primary in vitro screening of the synthesized compounds was performed against Staphylococcus aureus, three methicillin-resistant S. aureus strains, Mycobacterium tuberculosis H37Ra and M. avium subsp. paratuberculosis. Some of the tested compounds showed antibacterial and antimycobacterial activity against the tested strains comparable with or higher than that of the standards ampicillin or rifampicin. 3-Hydroxy-N-(2-propoxyphenyl)naphthalene-2-carboxamide and N-[2-(but-2-yloxy)-phenyl]-3-hydroxynaphthalene-2-carboxamide had MIC = 12 μM against all methicillin-resistant S. aureus strains; thus their activity is 4-fold higher than that of ampicillin. The second mentioned compound as well as 3-hydroxy-N-[3-(prop-2-yloxy)phenyl]-naphthalene-2-carboxamide had MICs = 23 μM and 24 μM against M. tuberculosis respectively. N-[2-(But-2-yloxy)phenyl]-3-hydroxynaphthalene-2-carboxamide demonstrated higher activity against M. avium subsp. paratuberculosis than rifampicin. Screening of the cytotoxicity of the most effective antimycobacterial compounds was performed using THP-1 cells, and no significant lethal effect was observed for the most potent compounds. The compounds were additionally tested for their activity related to inhibition of photosynthetic electron transport (PET) in spinach (Spinacia oleracea L.) chloroplasts. N-(3-Ethoxyphenyl)-3-hydroxynaphthalene-2-carboxamide (IC50 = 4.5 μM) was the most active PET inhibitor. The structure-activity relationships are discussed.
- Gonec, Tomas,Zadrazilova, Iveta,Nevin, Eoghan,Kauerova, Tereza,Pesko, Matus,Kos, Jiri,Oravec, Michal,Kollar, Peter,Coffey, Aidan,O'Mahony, Jim,Cizek, Alois,Kralova, Katarina,Jampilek, Josef
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p. 9767 - 9787
(2015/08/06)
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- A molecular insight on the supramolecular assembly of thiophene polymers
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Herein, the relationship between supramolecularly self-assembled microstructures and the chemical structures of photoluminescent molecules is discussed. A series of non-amphiphilic molecules with different length alkyl chains (4-14), central mesogenic groups, and chemical linkers were designed and synthesized. Intricate analysis shows that the supramolecular assembly varies with change in torsion angle of the thiophene linking group on elongation of the alkyl chain. Small angle X-ray scattering measurement shows long range molecular interaction for lower alkyl chain length, AFM reveals circular domains for octyl and decyl alkyl group polymers. UV-Visible and photoluminescence studies in solution and thin-film show that the J-aggregate patterns for the circular domain of the polymer backbone has a major effect on the polymer absorbance, and produces a larger shift for the photoluminescence signals at higher wavelengths. Excitation polarisation studies show a change in molecular ordering in various colour regions with change in aggregation by means of maximum dichroic ratio for the circular domain assembly. Charge carrier mobility and cyclic voltammetry studies show higher mobility and reduced band gap for these circular domain polymers. Dynamic light scattering studies of octyl alkyl chain polymers show a bimodal distribution, which shows the apparent nature of anisotropy in solution. The Royal Society of Chemistry.
- Suryanarayanan, Chandrasekaran,Ravindran, Ezhakudiyan,Ananthakrishnan, Soundaram Jeevarathinam,Somanathan, Narayanasastri,Mandal, Asit Baran
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p. 18975 - 18982
(2012/10/29)
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- Liquid-crystalline polymorphism of 4-heptyloxybenzylidene-4′- alkyloxyanilines and their phase equilibrium with 4-octyloxyphenyl 4-nitrobenzoate
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This paper describes the synthesis and liquid-crystalline properties of the homologous series of 4-heptyloxybenzylidene-4′-alkyloxyanilines (7-n). Six of them are presented for the first time. Based on the polarization microscopy (POM and TOA methods) and the calorimetric (DSC) measurements following polymorphism has been detected: nematic, smectic C and smectic I mesophases. The presence of these mesophases was confirmed by the miscibility method, using 4-octyloxyphenyl 4-nitrobenzoate and terephtal-bis (4-butyloaniline) as a mesophase references. Extraordinary results have been found in the mixtures of the investigated compounds with 4-octyloxyphenyl 4-nitrobenzoate; Induced smectic A has been observed, which is connected with very strong intermolecular interactions. Additionally destabilization of nematic and smectic C phases was visible.
- Godzwon, Joanna,Sienkowska, Monika J.,Galewski, Zbigniew
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scheme or table
p. 75 - 82
(2012/04/04)
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- An approach for differentiating isozymes. Construction of libraries containing short aromatic peptides as part of a method to design selective inhibitors against lipases
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Through synthesis and assays of peptidyl substrates, we could select substrates having peptidyl complementary against lipases. The best substrate showed 20-fold improved Km relative to non-peptidyl substrate. Using this information, we generated selective inhibitors. Lipase activities with peptidyl substrates were represented as fingerprints. Differences in fingerprints reflect different structures near active site of lipases, could be used for generating selective inhibitors.
- Park, Sangeun,Yu, Jaehoon
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supporting information; experimental part
p. 3147 - 3151
(2012/06/04)
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- Influences of hydrogen bonding and peripheral chain length on mesophase structures of mesogen-jacketed liquid crystalline polymers with amide side-chain linkages
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A series of mesogen-jacketed liquid crystalline polymers, poly{2,5-bis[(4-alkoxyphenyl)aminocarbonyl]styrene} (P-Cm, where m is the number of carbon atoms in the alkoxy groups, and m = 1, 4, 8, 12), with an amide core and flexible tails of varying lengths on the two ends in the side chain were designed and successfully synthesized via conventional radical polymerization. The mesophase structures of these polymers were dependent on the number of carbon atoms in the peripheral chains. Wide-angle X-ray diffraction and polarized light microscopy results revealed that the polymers with m ≥ 4 could form smectic A phases, while a columnar nematic phase could be formed for the polymer with methoxy end groups (P-C1). The hydrogen bonding among the side-chain amide groups might play an important role in forming and stabilizing these liquid crystalline phases, which was suggested by the results from variable-temperature FTIR and 2D IR analyses.
- Cheng, Yan-Hua,Chen, Wen-Ping,Shen, Zhihao,Fan, Xing-He,Zhu, Mei-Fang,Zhou, Qi-Feng
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experimental part
p. 1429 - 1437
(2011/10/07)
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- Studies of calamitic liquid crystalline compounds involving ester-azo central linkages with a biphenyl moiety
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Two mesogenic homologous series involving ester-azo central linkages with a biphenyl moiety have been synthesized, such as 4'-[(4-n-alkoxyphenyl)diazenyl] biphenyl-4-ol (series I) and 4'-[(4-n-alkoxyphenyl) diazenyl]-4-butoxy phenyl biphenyl-4-carboxylate (series II). Azobiphenyl of series I having a free hydroxyl group with strong hydrogen bonding exhibits a high-temperature enantiotropic smectic phase. Whereas in series II, compounds containing C 1-C8 carbon atoms exhibit only a monotropic smectic phase and compounds with C10, C12, C14, and C 16 atoms show an enantiotropic smectic phase. These compounds were characterized by elemental analysis, FT-IR, 1H-NMR, and mass spectral studies. The phase transition and mesogenicity of these substances were studied by polarizing optical microscopic and differential scanning calorimetric techniques. Their thermal stabilities and other characteristics are discussed. Copyright Taylor &Francis Group, LLC.
- Thaker,Dhimmar,Patel,Solanki,Patel,Chothani,Kanojiya
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experimental part
p. 172 - 191
(2012/07/27)
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- Novel supramolecular organocatalysts of hydroxyprolinamide based on calix[4]arene scaffold for the enantioselective Biginelli reaction
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A series of novel supramolecular organocatalysts of hydroxyprolinamide based on the upper rim of calix[4]arene scaffold have been developed to catalyze enantioselective multi-component Biginelli reaction. Under the optimal conditions, the reactions occurred with moderate-to-excellent enantioselectivities (up to 98% ee). A plausible transition state constructed by the supramolecular interaction of hydrogen bond and cation-π between catalysts and substrates has been proposed.
- Li, Zhengyi,Xing, Huaijie,Huang, Guoli,Sun, Xiaoqiang,Jiang, Juli,Wang, Leyong
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experimental part
p. 1726 - 1734
(2012/04/18)
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- Role of terminal heterocyclic ring on mesomorphic properties of homologous series
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Two new homologous series of compounds with a heterocyclic ring having sulfur and oxygen as a hetero atom derived from p-hydroxy acetophenone and alkoxy aniline containing cinnamate-azomethine as central linkages have been synthesized. viz. 4(furalacryloxy) α-methyl benzylidine-4′-alkoxy aniline and 4(thianylacryloxy) α-methyl benzylidine-4′-alkoxy aniline. The compound of both the series have been characterized by elemental analysis, FT-IR, 1H-NMR, and mass spectrometry method. Their liquid crystalline properties have been investigated by optical polarizing microscopy and differential scanning calorimetry (DSC) studies. All the derivatives are mesomorphic in nature showing the nemetic phase. The mesomorphic properties of the present two series are compared with other structurally related series to evaluate the effect of thiophene and furan on mesomorphism. Copyright Taylor & Francis Group, LLC.
- Thaker,Patel,Solanki,Dhimmer,Dave
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experimental part
p. 63 - 80
(2010/09/05)
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- Fused ring compound and use thereof
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The present invention provides a compound represented by the formula: wherein the symbols are as described in the specification, or a salt thereof, which is useful for preventing/treating eicosanoid-associated diseases such as atherosclerosis, diabetes, obesity, atherothrombosis, asthma, fever, pain, cancer, rheumatism, osteoarthritis and atopic dermatitis, and which has an excellent pharmacological action, physicochemical properties, etc.
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Page/Page column 40
(2010/08/07)
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- Novel Prolinamide Organocatalysts Based on Calix[4]arene Scaffold for the Enantioselective Direct Aldol Reaction
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A series of novel prolinamide organocatalysts based on calix[4]arene scaffold have been developed to catalyze the direct asymmetric aldol reaction of aromatic aldehydes and cyclohexanone. Under the optimal condition, high isolated yields (up to 99%) and enantioselectivities (up to 97% ee), and moderate diastereoselectivities (up to 85/15) were obtained.
- Li, Zheng-Yi,Lu, Cheng-Xi,Huang, Guoli,Ma, Jie-Jie,Sun, Hongsheng,Wang, Leyong,Pan, Yi
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scheme or table
p. 461 - 466
(2011/09/14)
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- One-dimensional to three-dimensional electronic conduction in liquid crystalline mesophases
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We have established the electronic conduction in the nematic phase of a small molecule of a 2-phenylbenzothiazole derivative, i.e., 2-(4'- octyloxyphenyl)-6-butoxybenzothiazole (8O-PBT-O4). This gives a new insight into the quest for the electronic conduction in liquid crystals, which was initiated by Kusabayashi and Labes in late 1960s and had succeeded over several decades, leading it to the end. In addition, it is clarified that the ionic conduction often observed in less ordered mesophases is induced with trace amounts of chemical impurities due to its low viscosity. The present result indicates that the charge carrier transport in the mesophase is electronic in its intrinsic nature irrespective of mesophases and molecular sizes, i.e., 1D-electronic conduction in columnar phase, 2D-electronic conduction in smectic mesophases, and 3D-electronic conduction in the nematic phase.
- Tokunaga, Keiji,Takayashiki, Yukiko,Iino, Hiroaki,Hanna, Jun-Ichi
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scheme or table
p. 250 - 258
(2010/06/15)
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- Charge carrier transport properties in liquid crystalline 2-phenylbenzothiazole derivatives
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We synthesized liquid crystalline 2-phenylbenzothiazole derivatives and investigated their charge carrier transport properties by time-of-flight experiments. These materials show less ordered phases such as smectic A, smectic C, and nematic phases at temperature range lower than 100°C, and their mobility was relatively small, from 10-5cm2/Vs to 10 -4cm2/Vs. In addition, the mobility depends on temperature, while it did not depend on electric fields. According to these results, we estimated the eneregy distribution of density of states responsible for condition, σ of Gaussian width, to be 78 ~ 118meV.
- Tokunaga, Keiji,Iino, Hiroaki,Hanna, Jun-Ichi
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scheme or table
p. 241 - 249
(2010/06/16)
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- Smectic polymorphism of 4-nonyloxybenzylidene-4′-alkyloxyanilines
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This paper describes liquid-crystalline polymorphism of the homologous series of 4-nonyloxybenzylidene-4′-alkyloxyanilines. Based on the polarization microscopy (POM, TOA) and the calorimetric (DSC) measurements the following mesophases were detected: nematic, smectic A, smectic C, smectic B, smectic I and smectic G. The presence of these mesophases was confirmed by the miscibility method, using: 4-heptyloxybenzilidene-4′-pentylaniline, 4-hexyl-4′-decyloxyazobenzene and 4-nonyloxybenzilidene-4′-butylaniline as mesophase references. Influence of the alkyl chain length on the type of mesophases and entropic effects of phase transition are discussed.
- Godzwon, Joanna,Sienkowska, Monika J.,Galewski, Zbigniew
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p. 259 - 267
(2008/03/13)
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- Symmetrical and unsymmetrical analogues of isoxyl; active agents against Mycobacterium tuberculosis
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Symmetrical and unsymmetrical analogues of the antimycobacterial agent isoxyl-have been synthesized and tested against Mycobacterium tuberculosis H37Rv and Mycobacterium bovis BCG, some showing an increased bactericidal effect. In particular, compounds 1-(p-n-butylphenyl)-3-(4-propoxy-phenyl) thiourea (10) and 1-(p-n-butylphenyl)-3-(4-n-butoxy-phenyl) thiourea (11) showed an approximate 10-fold increase in in vitro potency compared to isoxyl, paralleled by increased inhibition of mycolic acid biosynthesis in M. bovis BCG. Interestingly, these isoxyl analogues showed relatively poor inhibition of oleate production, suggesting that the modifications have changed the spectrum of biological activity.
- Bhowruth, Veemal,Brown, Alistair K.,Reynolds, Robert C.,Coxon, Geoffrey D.,Mackay, Simon P.,Minnikin, David E.,Besra, Gurdyal S.
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p. 4743 - 4747
(2008/12/23)
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- Solution phase parallel synthesis of 4-aminophenyl ethers using a carboxyl-functionalized ionic liquid as support
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A small sortiment of 4-aminophenyl ether derivatives was constructed with good yields and purities via Williamson reaction using the carboxyl- functionalized ionic liquid [cmmim][BF4] as soluble support. The recovered ionic liquid could be reused for several times with similar capacity. Springer-Verlag 2005.
- Peng, Yanqing,Yi, Fengping,Song, Gonghua,Zhang, Ying
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p. 1751 - 1755
(2007/10/03)
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- Copper-catalyzed formation of carbon-heteroatom and carbon-carbon bonds
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The present invention relates to copper-catalyzed carbon-heteroatom and carbon-carbon bond-forming methods. In certain embodiments, the present invention relates to copper-catalyzed methods of forming a carbon-nitrogen bond between the nitrogen atom of an amide or amine moiety and the activated carbon of an aryl, heteroaryl, or vinyl halide or sulfonate. In additional embodiments, the present invention relates to copper-catalyzed methods of forming a carbon-nitrogen bond between a nitrogen atom of an acyl hydrazine and the activated carbon of an aryl, heteroaryl, or vinyl halide or sulfonate. In other embodiments, the present invention relates to copper-catalyzed methods of forming a carbon-nitrogen bond between the nitrogen atom of a nitrogen-containing heteroaromatic, e.g., indole, pyrazole, and indazole, and the activated carbon of an aryl, heteroaryl, or vinyl halide or sulfonate. In certain embodiments, the present invention relates to copper-catalyzed methods of forming a carbon-oxygen bond between the oxygen atom of an alcohol and the activated carbon of an aryl, heteroaryl, or vinyl halide or sulfonate. The present invention also relates to copper-catalyzed methods of forming a carbon-carbon bond between a reactant comprising a nucleophilic carbon atom, e.g., an enolate or malonate anion, and the activated carbon of an aryl, heteroaryl, or vinyl halide or sulfonate. Importantly, all the methods of the present invention are relatively inexpensive to practice due to the low cost of the copper comprised by the catalysts.
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- Mesogenicity of organophosphazenes: The effect of phosphazene rings and side groups on the phase transition
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Cyclotriphosphazene and cyclotetraphosphazene derivatives with mesogenic 4-N-(4-alkoxyphenyl)iminomethyl)phenoxy and 4-(4′-alkoxy) biphenoxy moieties were synthesized. Schiff base moiety has higher mesomorphic stability than that in biphenyl moiety both in cyclotriphosphazene and cyclotetraphosphazene. Cyclotriphosphazenes possess higher thermal stability in the mesomorphic phase than the cyclotetraphosphazenes, suggesting the difference in the molecular structure.
- Moriya, Keiichi,Yamane, Toshihiro,Suzuki, Toshiya,Masuda, Tsuyoshi,Mizusaki, Hiroshi,Yano, Shinichi,Kajiwara, Meisetsu
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p. 1427 - 1432
(2007/10/03)
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- Copper-catalyzed coupling of aryl iodides with aliphatic alcohols.
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[reaction: see text] A simple and mild method for the coupling of aryl iodides and aliphatic alcohols that does not require the use of alkoxide bases is described. The reactions can be performed in neat alcohol. For more precious alcohols, the etherificat
- Wolter, Martina,Nordmann, Gero,Job, Gabriel E,Buchwald, Stephen L
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p. 973 - 976
(2007/10/03)
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- Mesogenic biphenyl derivatives with azo and ester central linkage
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Biphenyl nucleus comprises one of the most interesting research areas in the study of relations between chemical constitution and mesomorphic properties. Few biphenyl derivatives with azo and ester central linkage having following general formula have been synthesized and their mesomorphic properties were evaluated. Where R=-H, -OCH3, R'=-CH3, -OCH3, -OC2H5, -OC4H9; X=-H, -Br. All the synthesized compounds were characterized by elemental analysis and spectroscopic methods.
- Prajapati
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p. 769 - 777
(2007/10/03)
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- Synthesis and structure of 1,4-diazabutadiene liquid crystals
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Nine 1,4-diazabutadiene compounds, Ar-N=C(R)-C(R)=N-Ar, R=H, Me; Ar= H2n+1CnO-C6H4, 2,4-(H9C4O)(Me)-C6H3 were synthesized and their liquid crystal properties were studied through thermal polarizing microscopy. The X-ray single crystal structure of compound 9 (Ar-N=C(H)-C(H)=N-Ar, Ar=2,4-(Me)(H9C4O)C6H3) was tested. It is a monoclinic crystal system, space group P21/C with the unit cell parameters: a=7.0703(3)A, b=8.674(4)A, c=18.3115(8)A, β =95.392(1)°. V=1114.57(9)A3, z=2, Dc=1.134 Mg/m3, R=0.0490,Rw=0.1237.
- Zhao, Ke-Qing,Hu, Pin,Xu, Hong-Bo
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p. 801 - 808
(2007/10/03)
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- Synthesis of new metallomesogens containing Ni(II) and Cu(II) atoms
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A few new metallomesogens containing Ni(II) and Cu(II) atoms of the ligands 4-substituted 2′-hydroxy 4′(4″-n-hexadecyloxybenzoloxy)azobenzenes have been synthesized. The complexes have been characterized by C, H, N, microanalysis, IR, NMR and UV-Visible spectroscopies. Meso-morphic properties of all the ligands and complexes were investigated on a Leitz Laborlux 12 POL microscope provided with a heating stage.
- Prajapati,Shah
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- Smectic mesophase properties of dimeric compounds. 2. Distinct formation of smectic structures with antiferroelectric ordering and frustration
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We have prepared two series of dimeric compounds, which comprise the schiff's base mesogen, alkyl spacer with the carbon number of 5 and alkyl or alkoxy tail with the carbon number of m = 4 approx. 16. In these compounds, we observed three types of smectic liquid crystals, the single layer phase with the tail group randomly mixing with the spacer, the bilayer phase in which the segregation of the spacer and tail groups takes place and so two mesogenic layers are included within a repeat unit, the frustrated smectic phase in which the density modulation appears along the layer as well as the layer normal. The bilayer phase was found to be antiferroelectric and the frustrated smectic phase was considered to result from the two dimensional escape from the dipolar interaction. The phase behaviour with m and the structure and properties of each phase will be described in detail.
- Watanabe, Junji,Izumi, Tatuya,Niori, Teruki,Zennyoji, Masahito,Takanishi, Yoichi,Takezoe, Hideo
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- Liquid crystalline properties of azobenzenes: I. 4-methoxy-, 4-ethoxy-, 4-propoxy-and 4-butoxy-4′-alkyloxyazobenzenes
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Liquid crystalline properties of four series of azobenzenes, 4-methoxy-4-alkyloxyazobenzenes (azo-1-n), 4-ethoxy-4′-alkyloxyazobenzenes (azo-2-n), 4-propoxy-4′al-kyloxyazobenzenes (azo-3-n) and 4-butoxy-4′-alkyloxyazobenzenes (azo-4-n), were investigated. By polarizing microscopy nematic and smectic C mesophases were detected. By DSC and TOA thermo-optics the parameters of phase transitions were measured. A typical odd-even effect of the clearing temperature was found. No smectic phase was detected in the first three series, even for the longest alkyloxy chains. The smectic C appears for the first time in the butoxy family, starting from the undecyloxyl derivative. In each series a polymorphism in the solid state was detected, especially significant in the propoxy and butoxy family, that was explained in terms of the ODIC phases.
- Galewski,Hofmanska,Zielinska
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p. 1357 - 1371
(2007/10/03)
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- Mesogenic 4-(2,3-Epoxypropoxy)-4'-alkoxyazoxybenzenes
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Optimal conditions for preparation of 4-(2,3-epoxypropoxy)-4'-alkoxyazoxybenzenes were developed, and 10 mesogenic homologs (n = 1-10) possessing an extended nematic mesophase were synthesized.Nonyloxy and decyloxy derivatives of epoxyazoxybenzene exhibit also smectic mesomorphism.
- Burmistrov, V. A.,Kuz'mina, S. A.,Koifman, O. I.
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p. 351 - 353
(2007/10/03)
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- Mesogenic properties of liquid crystals having a chiral semiflexible joint
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Two homologous series of mesogenic enantiomers with chiral semiflexible joint, -C*H(CH3)CH2COO-, are examined. High twist power and presence of blue phases with short lattice period are found for eleven examined compounds. Some effects of chirality in reentrant system are discussed. On phase diagram of enantiomers the SmAd phase area is shifted toward longer homologues as compared to racemates. In result, an island of the SmAd phase in the cholesteric sea exists on binary phase diagrams of R- and S- enantiomers. Triple divergence of the pitch in the cholesteric phase of a pure compound is observed.
- Gorecha,Pyzuk,Mieczkowski
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- Phase transfer catalysis without solvent. Alkylation of phenol and derivatives
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The alkylation of phenol, hydroquinone and p-aminophenol is performed by phase transfer catalysis without solvent. High yields of α,ω-diphenoxyalkanes, hydroquinone diethers and high selective mono O-alkylation of p-aminophenol are obtained in very mild conditions.
- Loupy,Sansoulet,Diez-Barra,Carrillo
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p. 1465 - 1471
(2007/10/02)
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- Comparative Structure-Activity Relationships of Antifolate Triazines Inhibiting Murine Tumor Cells Sensitive and Resistant to Methotrexate
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The inhibitory effect of 108 4,6-diamino-1,2-dihydro-2,2-dimethyl-1-(substituted-phenyl)-s-triazines on murine L5178Y tumor cells, resistant and sensitive to methotrexate (MTX), has been studied.From the pI50 values, quantitative structure-activity relationships have been formulated which show that the lipophilic triazines are much more inhibitory against resistant cells than methotrexate or hydrophilic triazines.The results are compared with the behavior of other antifolate drugs that have been used in chemotherapy, as well as with eight antitumor drugs that are notantifolates.The acquired resistance of these cells toward hydrophilic antifolates may be attributed to the combined effect of an impaired active-transport system, a change in the conformation of dihydrofolate reductase in the resistant cells, and an amplified production of dihydrofolate reductase in the resistant cells.
- Selassie, Cynthia Dias,Hansch, Corwin,Khwaja, Tasneem A.,Dias, Cecilia B.,Pentecost, Stephanie
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p. 347 - 357
(2007/10/02)
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- NOVEL TRANSETHERIFICATION IN CATALYTIC REDUCTION OF 4-ALKOXYNITROBENZENES IN ALCOHOL-SULFURIC ACID SOLUTION
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In catalytic reduction (5percent Pt-C, 1 atm H2) of 4-alkoxynitrobenzenes (R1O-C6H4-NO2) in alcohol(R2OH)-sulfuric acid solution at room temperature, the reduction was found to be accompanied by transetherification to afford R2O-C6H4-NH2.
- Sone, Takaaki,Teraoka, Tadayoshi,Katada, Sho-ji,Ohkubo, Makoto,Karikura, Masami,et al.
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p. 1259 - 1262
(2007/10/02)
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- Process for producing alkoxyanilines
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Alkoxyanilines are produced by reacting a hydroxyaniline having the formula STR1 with an alkyl halide having the formula wherein R represents an alkyl group and X represents a halogen atom in the presence of an alkali metal alcoholate or hydroxide in a nonprotonic organic solvent selected from the group consisting of N-dimethyl acetamide, tetramethyl urea, hexamethylphosphoric triamide, dimethyl sulfoxide and N-methylpyrrolidone or a polyalkyleneglycol alkyl ether having the formula wherein R' represents an alkyl group having 1 to 4 carbon atoms and R" represents an alkylene group having 2 to 3 carbon atoms and n is an integer of 1 to 3.
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