- Synthesis and bacteriostatic activities of bis(Thiourea) derivatives with variable Chain Length
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A series of 1,4-bis(decoxyphenyl)carbamothioyl-Terephthalamide derivatives was successfully synthesised by reaction of benzene- 1,4-dicarbonyl isothiocyanate intermediates with long alkyl chain. The alkylation was performed via Williamson etherification o
- Halim, Ainaa Nadiah Abd,Ngaini, Zainab
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- The First tetrafluorinated azobenzene-imidazolium ionic conjugates as potential thermotropic liquid crystalline drugs: Self-assembly properties and cytotoxic effects
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A new series of tetrafluorinated azobenzene-imidazolium ionic liquid crystals (ILCs) of varying alkyl chain length (n = 10–18 in even parity) in the imidazolium cationic head group was prepared and characterized using FTIR and NMR spectroscopy, and elemen
- Babamale, Halimah Funmilayo,Chear, Nelson Jeng-Yeou,Haque, Rosenani A.,Khor, Boon-Keat,Yam, WanSinn
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- Synthesis and characterization of azobenzene derivatives and azobenzene-imidazolium conjugates with selective antimicrobial potential
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Five new non-fluorinated and fluorinated azo derivatives, as well as a new series containing five azo-imidazolium conjugates of varying alkyl chain length in the imidazolium head group were prepared and characterized using FTIR and NMR spectroscopy, and e
- Babamale, Halimah Funmilayo,Sangeetha, Thiagarajan,Tan, Joo Shun,Yam, WanSinn
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- Polarization effect in luminescent mesogenic BF2 complexes derived from heterocyclic benzothiazoles
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Two series of benzo(thia)xazoles 1–2 and one series of boron difluoride complexes 2-BF2 derived from benzothiazoles 2 were reported, and their mesomorphic and optical properties were investigated. The crystal and molecular structures of compound 2 and 2-BF2 (all n = 8) were determined by means of X?ray structural analysis, and both crystallize in the triclinic P-1 and monoclinic P21/c. The geometry at boron center is perfectly tetrahedral, and the overall molecular shapes are considered as rod?shape. Both benzo(thia)xazoles 1 and 2 exhibited N or/and SmC phase, and boron complexes 2-BF2 formed N or/and SmC phase. Benzothiazoles 2 showed a much wider temperature range of mesophase than those of benzoxazoles 1, which were attributed to the better polarization by sulfur atom incorporated. Boron complexes 2-BF2 (n = 10, 12) emitted a yellow?to?green emission at λmax = 569–571 nm in CH2Cl2. This is the first mesogenic BF2 complexes derived from benzothiazoles.
- Hsu, Yuan?Chun,Wang, Chun?Yang,Hsiao, Pei?Chi,Cai, Yi-Hong,Lee, Gene?Hsiang,Lai, Chung K.
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- Chiral polymorphism in new imine based rod-like liquid crystals
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New imine based rod-like compounds, composed of three-benzene-ring molecular core linked with azomethine as well as ester groups and terminated with (S)-3,7-dimethyloctyloxy chiral unit at one side have been synthesized. The other terminal position has been varied by using n-octyloxy/decyloxy/dodecyloxy groups to reveal chain length effect on mesophase behavior. The liquid crystalline properties of the new compounds have been investigated by polarizing optical microscopy, differential scanning calorimetry and electro-optic studies. The novel chiral calamitics derived from Schiff base or salicylaldimine-core show a chiral polymorphism comprising of blue phase and chiral nematic as well as smectics such as chiral tilted smectic and unidentified smectic mesophase.
- ?a?lar, Fatma P?nar,Akda?-K?l??, Huriye,Eran, Belk?z Bilgin,Ocak, Hale
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- Thermotropic Liquid-Crystalline and Light-Emitting Properties of Bis(4-aalkoxyphenyl) Viologen Bis(triflimide) Salts
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A series of bis(4-alkoxyphenyl) viologen bis(triflimide) salts with alkoxy chains of different lengths were synthesized by the metathesis reaction of respective bis(4-alkoxyphenyl) viologen dichloride salts, which were in turn prepared from the reaction of Zincke salt with the corresponding 4-n-alkoxyanilines, with lithium triflimide in methanol. Their chemical structures were characterized by 1H and 13C nuclear magnetic resonance spectra and elemental analysis. Their thermotropic liquid-crystalline (LC) properties were examined by differential scanning calorimetry, polarizing optical microscopy, and variable temperature X-ray diffraction. Salts with short length alkoxy chains had crystal-to-liquid transitions. Salts of intermediate length alkoxy chains showed both crystal-to-smectic A (SmA) transitions, Tms, and SmA-to-isotropic transitions, Tis. Those with longer length of alkoxy chains had relatively low Tms at which they formed the SmA phases that persisted up to the decomposition at high temperatures. As expected, all of them had excellent thermal stabilities in the temperature range of 330-370 ?C. Their light-emitting properties in methanol were also included.
- Agra-Kooijman, De?a M.,Al-Karawi, Muhammed Kareem M.,Bhowmik, Pradip K.,Chang, Anthony,Chen, Si L.,Cortez, Raymond G.,Dizon, Erenz J.,Fisch, Michael R.,Gutierrez, Bryan,Han, Haesook,Ho, Andy,Killarney, Shane T.,Kim, Jongin,Kumar, Satyendra,Mandal, Hari D.,Mendez, Klarissa,Principe, Ronald Carlo G.,Sharpnack, Lewis
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- Synthesis, liquid crystalline properties and photo switching properties of coumarin-azo bearing aliphatic chains: Application in optical storage devices
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A series of novel azo-coumarin derivatives with different aliphatic chain length (3a-e) have been synthesized and characterized for liquid crystal properties and their photoswitching behavior. The incorporation of coumarin along with azobenzene was prepared via esterification reaction and differ in the length of alkyl group, CnH2n+1, where n = 6, 8, 10, 12 and 14. Azo-coumarin bearing C14 alkyl chain shows Smectic–A phase while azo-coumarin bearing rest of long alkyl chain exhibited Nematic phase. The incorporation of natural product moieties into azobenzene network has increased electron delocalisation and liquid crystal properties. The photoswitching properties of said molecules were tested and the coumarin-azo compounds 3a-e took ~46 s to reach photostationary state during UV illumination and exhibited long thermal back relaxation time (~16 h) in solutions. Device is also fabricated to see the performance of the device with respect to the alkyl chain length. Presented studies show the importance of azo-coumarin derivatives with different chain length for the application of optical storage devices.
- Madiahlagan, Eswaran,B N, Sunil,Ngaini, Zainab,Hegde, Gurumurthy
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- Structurally simple trimesic amides as highly selective anion channels
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Trimesic amide molecules, which contain simple alkyl chains in their periphery, exhibit interesting anion-transport functions. The most active and highly selective channel TA12 efficiently transports ClO4? anions across membranes, with other anions conducted in the order of I? > NO3? > Br? > Cl?.
- Yuan, Lin,Shen, Jie,Ye, Ruijuan,Chen, Feng,Zeng, Huaqiang
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supporting information
p. 4797 - 4800
(2019/05/02)
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- New long-chain donor-acceptor-donor pyromellitic diimide (PMDI) derivatives. A combined theoretical and experimental study
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This study involves the electrochemical, thermal and photophysical profiling of new pyromellitic diimide (PMDI) derivatives containing alkyl chains of different sizes. The photophysical investigation shows that all compounds exhibited absorption in the UV-B region (~290 nm). The band-gaps were calculated by onset peak values of around 4.03 eV. The compounds are photoactive in the UV-A region (312–328 nm) with a small solvatochromic effect in the excited state (Δλem = 16 nm). The electrochemical studies revealed that the reduction of the bisimide moiety showed two waves due to the formation of both the radical anion and a dianion. On the other hand, oxidation showed two waves due to the formation of radical cations and dications. The thermal properties were measured by differential thermal analysis (DTA) and thermogravimetric analysis (TGA), and the materials showed high thermal stability (Td > 300 °C). Theoretical calculations were also performed to study the geometry and charge distribution of these compounds in their ground and excited electronic states. No significant changes in the absorption and emission maxima were found by changing the solvent or substituents attached to the PMDI structure.
- Dal-Bó, Alexandre Gon?alves,da Costa Duarte, Rodrigo,Cercená, Rodrigo,Peterson, Michael,Rafique, Jamal,Saba, Sumbal,Zapp, Eduardo,Gil, Eduarda Sangiogo,Bruno Gon?alves, Paulo Fernando,Rodembusch, Fabiano Severo,Frizon, Tiago Elias Allievi
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p. 143 - 150
(2018/05/07)
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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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p. 15044 - 15051
(2018/09/29)
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- Luminescent mesogenic borondifluoride complexes with the Schiff bases containing salicylideneamines and β-enaminoketones core systems
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Three new families of borondifluoride complexes 1a–c derived from salicylideneamines 2a and β-enaminoketonates 2b–c were reported, and their mesomorphic and optical properties were also investigated. One single crystal and molecular structure of nonmesogenic BF2 complex 1c (n = 10) was resolved and the geometry of the central boron atom was tetrahedron. A larger dihedral angle of 81.3° between the two phenyl rings observed in crystal lattice was attributed to the lack of liquid crystallinity. Boron complexes 1a formed monotropic SmA phases, while boron complexes 1b exhibited enantiotropic SmC mesophases. The optical property of the boron complexes was dependent on their molecular structures, and they emitted a blue–to–green emission at λmax = 476–541 nm in the solution and 488–550 nm in the solid state. This is the first group of mesogenic BF2 complexes with the Schiff bases derived from respective salicylideneamines and β-enaminoketones.
- Lei, Zih-Yang,Lee, Gene-Hsiang,Lai, Chung K.
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- Liquid crystal semiconductor material as well as preparation method and application of liquid crystal semiconductor material
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The invention discloses a liquid crystal semiconductor material as well as a preparation method and application of the liquid crystal semiconductor material. The liquid crystal semiconductor materialcomprises an organic semiconductor mother nucleus gene, a photochromic gene and a thermotropic liquid crystal gene, wherein the organic semiconductor mother nucleus gene is the core part of the wholemolecule, the characteristics of being sensitive to ultraviolet light and visible light of the photochromic gene can be transformed in conformation or structure, and the thermotropic liquid crystal gene endows the molecule with the characteristic of liquid crystal phase so as to enable molecules to be arranged more orderly by utilizing the superior liquid crystal characteristic, so as to further realize the thermotropic semiconductor material and increase the migration rate. By adopting an evaporation manner, the liquid crystal semiconductor material disclosed by the invention is prepared intoan organic thin film transistor, after irradiation with ultraviolet light, device performance is obviously promoted, and under the dual actions of ultraviolet light and annealing, device performanceis further promoted. Such functional semiconductor material realizes application of specific potentials thereof to photoelectric devices, such as intelligent devices, sensors and functional switches.
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Paragraph 0034; 0039; 0041; 0049; 0052; 0054
(2018/07/30)
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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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- Decoquinate derivatives: A new class of potent antischistosomal agents against Schistosoma japonicum
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Decoquinate (1), an old and inexpensive coccidiostat, exhibited potent antimalarial activity, however, its antischistosomal activity against Schistosoma japonicum has not yet been evaluated. Based on decoquinate, a series of decoquinate derivatives was designed, synthesized, evaluated as a new class of antischistosomal agents against S. japonicum adult worms in vitro. Among them, compound 15 killed 100% of adult S. japonicum in 72?h at the concentration of 10?μmol/L in vitro, exhibited stronger worm-killing activity than PZQ in vitro and could serve as a promising lead compound to develop new antischistosomal agents.
- Wang, Wen-Long,Song, Li-Jun,Hu, Bo-Chun,Miao, Li,Chen, Xiao-Yu,Fan, Wen-Hua,Yin, Xu-Ren,Shen, Shuang,Ding, Zhao-Feng,Yu, Chuan-Xin
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p. 1547 - 1552
(2017/07/17)
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- Benzene ring containing cationic gemini surfactants: Synthesis, surface properties and antibacterial activity
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New quaternary ammonium gemini surfactants of the general formula CnH2n?+?1-Ph-NHCOCH2N+(CH3)2-(CH2)s-N+(CH3)2CH2CONH-Ph-CnH2n?+?1 (with n?=?8, 10, 12, 14, 16 and s?=?2, 4, 6) have been synthesized by an efficient synthetic pathway based on the quaternization of N,N,N′,N′-tetramethylalkylenediamine with 2-bromo-N-(4-(alkyloxy) phenyl) acetamides. Their surface properties were investigated by surface tension, electrical conductivity and dynamic light scattering (DLS) measurements. The study shows that the incorporation of a benzene ring in the hydrophobic tail prompts micelle formation which leads to a smaller cmc values in the range of 0.21–0.009?mM compared to analogous geminis bearing alkyl hydrophobic chains. The length of the spacer and the hydrophobic chain has a pronounced effect on the aggregation behavior of surfactants molecules. This was confirmed by the average surfaces occupied by these molecules at the water–air interface calculated from the Gibbs equation. The size of the aggregates was measured by employing dynamic light scattering technique. The antimicrobial activity of investigated surfactants was evaluated against three microorganisms: Staphylococcus aureus, Escherichia coli and Candida albicans.
- Taleb, Khadidja,Mohamed-Benkada, Mustapha,Benhamed, Nadjia,Saidi-Besbes, Salima,Grohens, Yves,Derdour, Aicha
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- [1,2,3]-triazole derivatives: Mesomorphic property dependence on the molecular shape
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Nowadays, heterocyclic units have been extensively studied for the preparation of thermotropic liquid crystals due to their ability to impart lateral and/or longitudinal dipoles and induce changes in molecular shape. Key parameters to accede to stable mesophases are the position of the heterocycle and the nature of terminal and linking functions. We present in this paper, an overview of several series of 1,2,3-triazole liquid crystalline derivatives that we designed and characterized. We highlight the effect of different connecting functions and the geometry of mesogenic core on the mesomorphic behavior of these derivatives.
- Benallou, Souria,Saidi-Besbes, Salima,Grelet, Eric,Bentaleb, Ahmed
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p. 290 - 298
(2017/05/26)
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- Novel Synthetic Monothiourea Aspirin Derivatives Bearing Alkylated Amines as Potential Antimicrobial Agents
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A new series of aspirin bearing alkylated amines moieties 1-12 were synthesised by reacting isothiocyanate with a series of aniline derivatives in overall yield of 16-56%. The proposed structures of all the synthesised compounds were confirmed using elemental analysis, FTIR, and 1H and 13C NMR spectroscopy. All compounds were evaluated for antibacterial activities against E. coli and S. aureus via turbidimetric kinetic and Kirby Bauer disc diffusion method. Compound 5 bearing meta -CH3 substituent showed the highest relative inhibition zone diameter against tested bacteria compared to ortho and para substituent. Furthermore, aspirin derivatives bearing shorter chains exhibited better bacterial inhibition than longer alkyl chains.
- Nordin, Norsyafikah Asyilla,Chai, Tchan Wei,Tan, Bee Ling,Choi, Ching Liang,Abd Halim, Ainaa Nadiah,Hussain, Hasnain,Ngaini, Zainab
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- Multi-responsive metal-organic lantern cages in solution
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Soluble copper-based M4L4 lantern-type metal-organic cages bearing internal amines were synthesized. The solution state integrity of the paramagnetic metal-organic cages was demonstrated using NMR, DLS, MS, and AFM spectroscopy. 1D s
- Brega, Valentina,Zeller, Matthias,He, Yufan,Peter Lu,Klosterman, Jeremy K.
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supporting information
p. 5077 - 5080
(2015/03/30)
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- Novel organogelators based on pyrazine-2,5-dicarboxylic acid derivatives and their mesomorphic behaviors
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A series of new low molecular organogelators (LMOGs) with thermotropic mesophase were synthesized via the reaction of 3,6-dimethyl-pyrazine-2,5- dicarboxylic acid with p-alkoxyl anilines. These compounds readily formed stable gels in a variety of organic solvents and their self-assembly behavior, structure-property relationship were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), 1H nuclear magnetic resonance (1H NMR), Fourier transform infrared spectroscopy (FTIR) and ultra-violet-visible spectroscopy (UV). The results showed a combination of intra-hydrogen bonding, π-π stacking and van der Waals interaction resulted in the aggregation of the organogelators to form three-dimension fibrous networks. The gels formed were multi-responsive to environmental stimuli, such as temperature, fluorinion, and shear stress. More importantly, all the organogelators exhibited thermotropic hexagonal column mesophase as revealed by differential scanning calorimetry (DSC), polarized optical microscopy (POM), and variable temperature XRD studies. A control compound was synthesized and its gelling ability was also checked.
- Huang, Yao-Dong,Tu, Wei,Yuan, Yu-Qin,Fan, Dong-Li
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supporting information
p. 1274 - 1282
(2014/02/14)
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- Phototunable liquid-crystalline phases made of nanoparticles
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The properties of liquid-crystalline (LC) hybrid systems made of inorganic nanoparticles grafted with photosensitive azo compounds are presented. For materials with a large density of azo ligands at the surface, the LC structure can be reversibly melted by UV light, and the return to the LC state does not require the absorption of visible light. For systems with a lower density of azo ligands, UV light causes shortening of the distance between metal sublayers in the lamellar phase. Interestingly, the azo derivatives attached to the nanoparticle surface show very different kinetics of cis/trans conformational change as compared to the free molecules. The cis form of free ligands in solution is stable for days, whereas the isomerization of molecules attached to the nanoparticle surface to the trans form takes only a few minutes. Apparently, owing to the crowded environment, azo ligands immobilized at a metal surface behave as they would in the condensed state.
- Zep, Anna,Wojcik, Michal M.,Lewandowski, Wiktor,Sitkowska, Kaja,Prominski, Aleksander,Mieczkowski, Joef,Pociecha, Damian,Gorecka, Ewa
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supporting information
p. 13725 - 13728
(2015/04/16)
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- Bent-core luminescent and electroactive bis(triazolyl)triazines with compact columnar mesomorphism
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The bulk self-assembly of bent-core molecules based on the novel structure 2-methoxy-4,6-bis(1′,2′,3′-triazol-4′-yl)-1,3, 5-triazine is reported together with their luminescent and electrochemical properties. Two families of compounds with lateral branches of different lengths have been investigated. Columnar mesomorphism with short stacking distances and periodic twisted structures were found. A compound exhibiting two hexagonal columnar mesophases that show different emission spectra and a transition from a bimolecular assembly to a unimolecular assembly is described.
- Beltran, Eduardo,Robles-Hernandez, Beatriz,Sebastian, Nerea,Serrano, Jose Luis,Gimenez, Raquel,Sierra, Teresa
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p. 23554 - 23561
(2014/07/07)
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- Structure-property correlation of benzoyl thiourea derivatives as organogelators
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A series of N-benzoyl-N′-aryl thiourea derivatives (1-4) can form stable gels from a variety of organic solvents ranging from protic to aprotic or polar to apolar at concentrations below 5 mg/mL. The gelation properties and structures of the resulting gels were investigated by 1H-NMR, FTIR, UV-vis, SEM, and XRD. The gels were anion-responsive and the driving forces for its formation were the hydrogen bonding and van der Waals interaction. The SEM images of the xerogels prepared from the organogels formed in acetonitrile, cyclohexane and acetone showed a network of elongated fibers. The results of XRD suggested that the dry gels had a layer structure.
- Huang, Yao-Dong,Dong, Xue-Lin,Zhang, Li-Li,Chai, Wei,Chang, Ji-Young
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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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- Designer ionic liquid crystals based on congruently shaped guanidinium sulfonates
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Ionic liquid crystals are mesogenic compounds that consist of cations and anions, usually rod-like cations and spherical anions. Herein we report a new method for the synthesis of ionic liquid crystals by using cations and anions of the same molecular shape with oppositely charged head groups. Thus, 4-alkoxyphenylpentamethylguanidinium 4-alkoxyphenylsulfonate ion pairs have been synthesised. 4-Alkoxyphenylpentamethylguanidinium iodides were also prepared to determine the influence of congruently shaped anions, in comparison with their spherical counterparts, on mesophase behaviour, which was investigated by differential scanning calorimetry (DSC), polarising optical microscopy (POM) and X-ray diffraction (XRD). All the liquid crystalline salts exhibit smectic A mesophases with strongly interdigitated bilayer structures. The guanidinium sulfonate ion pairs show mesomorphic properties from shorter alkyl chain lengths (≥C9) and lower melting points (≈10 K), whereas the corresponding guanidinium iodides are liquid crystalline for longer alkyl chain lengths (≥C14). For chains with ≥C18, however, the mesophase range decreases for the sulfonate ion pairs, but not for the iodide salts. Tuning mesophase stability: Guanidinium sulfonate ion pairs with congruently shaped anions and cations with short alkyl chains R (see scheme) have favourable mesogenic properties with respect to mesophase stability in comparison with their guanidinium counterparts with spherical iodide anions. Copyright
- Butschies, Martin,Frey, Wolfgang,Laschat, Sabine
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p. 3014 - 3022
(2012/04/10)
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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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p. 172 - 191
(2012/07/27)
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- PHTHALANILATE COMPOUNDS AND METHODS OF USE
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The invention provides antimicrobial compounds and compositions, and methods of using them. The compounds and compositions include, for example, a compound of any one of Formulas I-X. The invention further provides methods of preparing the compounds, and useful intermediates for their preparation. The compounds can possess highly specific and selective activity, such as antibacterial activity and/or enzymatic inhibitory activity. Accordingly, the compounds and compositions can be used to treat bacterial infections, or to inhibit or kill bacteria, either in vitro or in vivo.
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Page/Page column 55
(2011/04/14)
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- Synthesis and biological evaluation of novel N-(alkoxyphenyl)-aminocarbonylbenzoic acid derivatives as PTP1B inhibitors
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Based on the fact that petroselinic acid showed good inhibitory activity (IC50=6.99μmol/L) against protein tyrosine phophatase 1B(PTP1B) in vitro, a series of novel N-(alkoxyphenyl)-aminocarbonylbenzoic acid derivatives were designed and synthesized. The results indicated that most of the derivatives showed more potent activities against PTP1B. Especially, compound 13 had obvious activity with an IC50 of 106nmol/L in vitro.
- Tong, Yuan Feng,Zhang, Pei,Chen, Feng,Hao, Ling Hua,Ye, Fei,Tian, Jin Ying,Wu, Song
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scheme or table
p. 1415 - 1418
(2011/10/09)
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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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- Synthesis of symmetric liquid crystal dimers based on azo and imine groups and investigation of phase behaviour by varying alkoxy terminal chain length
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With the objective to study the effect of alkoxy terminal chain length on mesomorphic properties of liquid crystals, we have synthesized two (Azo and Imine) different series of dimesogens by varying terminal alkoxy chain length (n = 6-12) with a short spacer unit in between two mesogens. Transition temperatures and phase characterization were studied by DSC, POM and XRD analysis. It was found that all the dimers show mesomorphic properties and the change in terminal alkoxy chain length has pronounced effect on the smectic phase window. In the DSC cooling scan, the smectic phase window of azo compounds increased from 6.4°C (2A6) to 16.0°C(2A12), whereas in Schiff base compounds, it increased from 9.2°C (2S6) to 31.0°C(2S12). Further, the 2A11 dimer was found to undergo photo induced configurational changes.
- Kim, Tae Hyeong,Lee, Chang Sin,Ramaraj,Jeon, Hye Jin,Song, Hyun Hoon,Lee, Soo Min,Yoon, Kuk Ro
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experimental part
p. 102 - 116
(2010/03/04)
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- Synthesis and liquid crystalline properties of novel triazene-1-oxide derivatives
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A new group of compounds, C6H5-N(O)=N-NH-C6H4-C(O)-O-C6H4-CH=N-C6H4-OR, (1), [R=n-alkyl group; 1a (R=C7H15 ) to 1h (R=C14H29)], has been designed and synthesized to develop triazene-1-oxide based liquid crystals. All the compounds have been characterized on the basis of their spectral data. Their thermal behavior has been examined and found to exhibit thermotropic liquid crystalline behavior over a wide range of temperature. All members of this family uniformly show nematic phase behavior on melting up to the clearing point during heating as well as on phase entering up to the solidification during cooling. An odd-even effect on transition temperatures has been observed during heating as well as cooling.
- Das, Purak,Biswas, Achintesh Narayan,Bandyopadhyay, Pinaki,Mandal, Pradip Kumar
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scheme or table
p. 3 - 15
(2010/03/24)
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- Multifunctional "clickates" as versatile extended heteroaromatic building blocks: Efficient synthesis via click chemistry, conformational preferences, and metal coordination
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Click chemistry has been utilized to access 2,6-bis(1-aryl-1,2,3-triazol-4- yl)pyridines (BTPs) as versatile extended heteroaromatic building blocks for their exploitation in supramolecular chemistry, in particular foldamer and ligand design. In addition to their high-yielding synthesis using Cu I-catalyzed Huisgen-type 1,3-dipolar cycloaddition reactions the formed triazole moieties constitute an integral part of the BTP framework and encode both its pronounced conformational preferences as well as its chelating ability. A diverse set of symmetrical and non-symmetrical BTPs carrying electron-donating and -withdrawing substituents at both terminal aryl and the central pyridine moieties has efficiently been synthesized and could furthermore readily be postfunctionalized with amphiphilic side chains and porphyrin chromophores. In both solution and solid state, the BTP scaffold adopts a highly conserved horseshoelike anti-anti conformation. Upon protonation or metal coordination, the BTP scaffold switches to the chelating syn-syn conformation. Iron and europium complexes have been prepared, successfully characterized by single-crystal X-ray diffraction analysis, and investigated with regard to their spin state and luminescent properties. The extended heteroaromatic BTP scaffold should prove useful for the design of responsive foldamer backbones and the preparation of new magnetic and emissive materials.
- Meudtner, Robert M.,Ostermeier, Marc,Goddard, Richard,Limberg, Christian,Hecht, Stefan
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p. 9834 - 9840
(2008/09/17)
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- Liquid crystal imidazolium salts: Towards materials for catalysis and molecular electronics
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1,3-Bis(4-alkyloxyphenyl)-3H-imidazol-1-ium trifluoromethanesulfonates, alkyl = CH3(CH2)n-1, n = 8, 10, 12, 14 and 16, can be derived from the analogous 4-alkyloxyphenylamines. These imidazolium salts exhibit a lamellar liquid-crystal mesophase between 99°C and 191°C. The smectic-A phase was fully characterised by polarising optical microscopy, differential scanning calorimetry and X-ray diffraction. We report also the synthesis, lamellar crystal structure and catalytic activity of the PdII complex of the (deprotonated) carbene form of one of these salts. In addition, we measured the charged carrier mobilities in the mesophase. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
- Suisse, Jean-Moise,Douce, Laurent,Bellemin-Laponnaz, Stephane,Maisse-Francois, Aline,Welter, Richard,Miyake, Yasuo,Shimizu, Yo
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p. 3899 - 3905
(2008/03/14)
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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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- Smectic and columnar liquid crystalline phases through charge-transfer interactions
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New heterocyclic electron donors based on a 1,3,5-triazine nucleus are presented. Three phenyl rings are grafted to the triazine core either via secondary amino groups or by a direct C,C-linkage and a specific number of decyloxy chains is attached to the
- Goldmann, Daniela,Nordsieck,Janietz, Dietmar,Frese, Thomas,Schmidt, Claudia,Wendorff, Joachim H.
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p. 337/[1379]-344/[1386]
(2007/10/03)
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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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- 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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- 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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- Synthesis of Certain Mesogenic Azomethines Derived from 4-Cycloalkylanilines and from 4-Cycloalkylbenzaldehydes
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General procedures are described for the synthesis of members of five pairs of related homologous series of mesogenic azomethines differing in the mode of linkage of the CH=N group and containing a cycloalkyl group in a terminal position.
- Byron, D. J.,Matharu, A. S.,Rees, M.,Wilson, R. C.
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p. 229 - 238
(2007/10/02)
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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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