121925-05-1Relevant academic research and scientific papers
Synthesis and mesomorphic characterization of some novel steroidal mesogens: A structure–property correlation
Bhat S, Vanishree,Kumar, Sandeep,Raghunathan, V. A.
, (2021/08/25)
The steroidal derivatives are found to be extremely good mesogens since their inception. Because of their inherent chirality, they have the potential to induce a wide variety of liquid crystalline phases, including frustrated phases depending upon the structure of the steroidal skeleton and the substituents attached. In this report, a series of novel monoalkoxy and dialkoxy benzoate derivatives of ergosterol and a few monoalkoxy derivatives of stigmasterol have been synthesized and their mesomorphic property has been investigated. The derivatives exhibited various mesophases including SmA, SmC*, N*, TGB and blue phases. Also, the gelation ability of some of these derivatives with various organic solvents has been examined. Furthermore, the mesomorphism of these derivatives has been compared with the analogous cholesteryl counterparts.
Molecular order and mesophase investigation of thiophene-based forked mesogens
Reddy, K. Rajasekhar,Lobo, Nitin P.,Narasimhaswamy
, p. 6897 - 6909 (2016/07/26)
Thiophene-based rodlike molecules constructed from a three phenyl ring core and terminal dialkoxy chains recognized as forked mesogens are synthesized, and their mesophase properties as well as the molecular order are investigated. The synthesized forked
Self-assembly of hekates-tris(N -salicylideneaniline)s into columnar structures: Synthesis and characterization
Achalkumar, Ammathnadu S.,Hiremath, Uma S.,Rao, D. S. Shankar,Prasad, S. Krishna,Yelamaggad, Channabasaveshwar V.
, p. 527 - 544 (2013/03/13)
Two series of new, photoluminescent star-shaped discotic liquid crystals, recently termed as "hekates", derived from tris(N-salicylideneaniline) s (TSANs), were synthesized by the facile threefold condensation of 3,4-bis(alkoxy)phenyl 4-aminobenzoates/3,4,5-tris(alkoxy) phenyl 4-aminobenzoates with 1,3,5-triformylphloroglucinol and characterized. These two series of discotics with six and nine peripheral n-alkoxy tails were especially designed and accomplished to understand the relation between mesomorphic/photophysical properties and molecular structure. Proton NMR spectral analysis revealed their existence as an inseparable mixture of two keto-enamine tautomeric forms featuring C3h and Cs rotational symmetries. A systematic study into the thermotropic liquid crystal behavior using polarizing optical microscopy, differential scanning calorimetry, and X-ray scattering confirmed the presence of columnar (Col) phase in vast majority of the TSANs prepared. The two-dimensional (2D) lattices of these fluid columnar phases were found to be characteristic of hexagonal Col (Col h), rectangular Col (Colr), or oblique Col (Col ob) phases depending on the number/length of the peripheral flexible chains. The stabilization of the Colob phase, a less commonly found fluid columnar structure, and the first of its kind in TSAN systems, implies very intensive intermolecular (face-to-face) interactions among the TSAN cores within the column. The photophysical properties were investigated both in solution and the columnar states by UV-vis absorption and photoluminescence; markedly, the solution state emits light in the blue region. The light-emitting ability of the Col phase is particularly significant given the possibility that, in such cores, the protons and electrons interact with each other through the H-bonding environment.
A new family of bent-core C2-symmetric liquid crystals
Hope-Ross, Kyle A.,Heiney, Paul A.,Kadla, John F.
supporting information; experimental part, p. 639 - 645 (2010/08/21)
A series of C2-symmetric compounds with different core sizes and varying lengths and numbers of alkoxy side chains were prepared, and the factors influencing their liquid crystalline mesophase behaviour were investigated. The compounds studied were based on benzophenone, dibenzylidene-acetone, and 1,9-diphenyl-nona-1,3,6,8-tetraen-5-one cores with either 1 or 2 linear alkoxy side chains. The side chains were varied in length from C6H13 to C12H25. The liquid crystalline mesophase behaviour of the compounds was investigated using differential scanning calorimetry, polarizing optical microscopy, and small-angle X-ray scattering (SAXS). It was found that a number of the molecules were able to self-assemble into smectic and nematic liquid crystalline phases.
Tailoring thermotropic cubic mesophases: Amphiphilic polyhydroxy derivatives
Borisch, Konstanze,Diele, Siegmar,Goering, Petra,Kresse, Horst,Tschierske, Carsten
, p. 529 - 543 (2007/10/03)
Novel amphiphilic polyhydroxy compounds [N-(3,4-dialkoxybenzoyl)-1-amino-1-deoxy-D-glucitols (glucamides), N-(3,4-dialkoxybenzoyl)-1-deoxy-1-methylamino-D-glucitols, N-(3,4,5-trialkoxybenzoyl)-1-deoxy-1-methylamino-D-glucitols (N-methylgucamides), 1-benzo
The synthesis and mesomorphism of di-, tetra- and hexa-catenar liquid crystals based on 2,2′-bipyridine
Rowe, Kathryn E.,Bruce, Duncan W.
, p. 331 - 341 (2007/10/03)
2,2′-Bipyridines are known to coordinate to a wide variety of metal centres. In this paper, liquid-crystalline two-chained (dicatenar), four-chained (tetracatenar) and six-chained (hexacatenar) bipyridines are synthesised and their mesomorphism is described. For the tetracatenar bipyridines, a full homologous series, from tetramethoxy to tetratetradecyloxy, was synthesised, and the phase diagram showed a classic progression from nematic and smectic C phases at short chain length, through a cubic phase to a columnar phase.
Influence of lateral alkoxy substitution on mesomorphic properties of copper complexes
Berdague, Philippe,Perez, Felix,Courtieu, Jacques,Bayle, Jean-Pierre
, p. 335 - 343 (2007/10/02)
Coordination complexes between copper and some lateral alkoxy chain-substituted N-(4-(4'-alkoxybenzoyloxy)salicylidene)-4-n-butylaniline have been synthesized.The lateral chain was introduced on the outer ring bearing the ester function.In the case of a 3,4-disubstitution, the mesomorphic behavior is related to the number of carbons in the terminal chain.If this is too small, the mesomorphic properties of the complexes disappear.In contrast, copper complexes are liquid crystalline and show more ordered phases by comparison with the free ligand.In case of a 2,4-disubstitution, the phases are nematic and the clearing temperatures are near room temperature, but the observed phases are essentially monotropic for the ligands, as well as for the complexes.Keywords: nematic / copper complex / lateral substitution / Schiff base
Selective etherification of polyhydroxybenzenes using PEG 200 as solvent or cosolvent
Berdague, P.,Perez, F.,Courtieu, J.,Bayle, J. P.
, p. 475 - 480 (2007/10/02)
The monoalkylation of hydroquinone is performed using PEG 200 as a solvent or a cosolvent.The effect on the selectivity of the base strength, the temperature, and the percentage of cosolvent are discussed.The substituted phenols were found to behave differently upon etherification.When a carboxylic function is present in the ring, the hydroxybenzoic acids were selectively etherified using pure PEG and sodium hydroxyde as a base.Substituted diphenols were selectively etherified using a mixture of PEG and dioxan and potassium hydrogencarbonate as a base.Keywords - etherification / selectivity / polyhydroxybenzenes / polyethylene glycol
Anthracycline derivatives having inhibitory activity against reverse transcriptase of human immunodeficiency virus
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, (2008/06/13)
As new compounds are now provided 14-O-(3,4-disubstituted benzoyl)adriamycins which are of low cytotoxicity and exhibit a high activity inhibitory to the reverse transcriptase of human immunodeficiency virus (HIV) and which can inhibit propagation of HIV.
