65039-19-2Relevant articles and documents
Polarization effect in luminescent mesogenic BF2 complexes derived from heterocyclic benzothiazoles
Hsu, Yuan?Chun,Wang, Chun?Yang,Hsiao, Pei?Chi,Cai, Yi-Hong,Lee, Gene?Hsiang,Lai, Chung K.
, (2019/12/09)
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.
Chiral polymorphism in new imine based rod-like liquid crystals
?a?lar, Fatma P?nar,Akda?-K?l??, Huriye,Eran, Belk?z Bilgin,Ocak, Hale
, (2020/07/06)
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.
Thermotropic Liquid-Crystalline and Light-Emitting Properties of Bis(4-aalkoxyphenyl) Viologen Bis(triflimide) Salts
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
, (2020/05/29)
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.
Structurally simple trimesic amides as highly selective anion channels
Yuan, Lin,Shen, Jie,Ye, Ruijuan,Chen, Feng,Zeng, Huaqiang
supporting information, p. 4797 - 4800 (2019/05/02)
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?.
Synthesis, liquid crystalline properties and photo switching properties of coumarin-azo bearing aliphatic chains: Application in optical storage devices
Madiahlagan, Eswaran,B N, Sunil,Ngaini, Zainab,Hegde, Gurumurthy
, (2019/07/31)
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.
Photoresponsive behavior of hydrophilic/hydrophobic-based novel azobenzene mesogens: Synthesis, characterization and their application in optical storage devices
Sunil,Yam, Wan Sinn,Hegde, Gurumurthy
, p. 40588 - 40606 (2019/12/25)
Three series of alkoxy chain-bearing azobenzene-derived quaternary ammonium iodides with an alkoxy chain at one end, namely N,N-diethanol-6-(4-((4′-alkyloxyphenyl)diazenyl)phenoxy)hexan-1-ammonium iodides, N-ethyl-N-ethanol-6-(4-((4′-alkyloxyphenyl)diazenyl)phenoxy)hexan-1-ammonium iodides and N,N-diethyl-6-(4-((4′-alkyloxyphenyl)diazenyl)phenoxy)hexan-1-ammonium iodides were synthesized and characterized. Their mesomorphic and photoswitching properties were examined via polarising optical microscopy (POM), differential scanning calorimetry (DSC) and UV-vis spectrophotometry. The liquid crystalline tilted schlieren texture of smectic C, non-tilted natural focal conic texture of smectic A and smectic B phases were observed in the N,N-diethanol- and N-ethyl-N-ethanol-bearing ammonium group substituted at the terminal via the alkoxy chain of the azo moiety. In these azo moieties, the equilibrium time for trans-cis isomerization was about 1 min and cis-trans isomerization occurred at around 590 min, which had the highest alkoxy chain and no hydroxyl group on their head group. The absence of a hydroxyl group on the terminal head group resulted in slow thermal back relaxation, whereas the hydroxyl group-bearing head group showed fast thermal back relaxation. These results suggest that the influence of the substituent on the cationic ammonium head group and alkoxy chain length on the photoisomerization of the azo compounds is vital for optical storage devices. Furthermore, the device fabricated using these materials demonstrated that they are excellent candidates for optical image storage applications.
Luminescent mesogenic borondifluoride complexes with the Schiff bases containing salicylideneamines and β-enaminoketones core systems
Lei, Zih-Yang,Lee, Gene-Hsiang,Lai, Chung K.
, p. 44 - 56 (2018/04/02)
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.
New long-chain donor-acceptor-donor pyromellitic diimide (PMDI) derivatives. A combined theoretical and experimental study
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
, p. 143 - 150 (2018/05/07)
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.
Columnar self-assembly of bowl shaped fluorescent liquid crystals based on calix[4]arene with Schiff base units
Sharma, Anuj S.,Sharma, Vinay S.,Vekariya, Rajesh H.
, p. 15044 - 15051 (2018/09/29)
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.
Benzene ring containing cationic gemini surfactants: Synthesis, surface properties and antibacterial activity
Taleb, Khadidja,Mohamed-Benkada, Mustapha,Benhamed, Nadjia,Saidi-Besbes, Salima,Grohens, Yves,Derdour, Aicha
, p. 81 - 90 (2017/06/13)
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.
