125151-57-7Relevant articles and documents
Synthesis, mesomorphic properties and nonlinear optical studies of alkyl and alkoxy phenylacetylene containing phenazine fused extended triphenylene discotic liquid crystalline dyes
Gowda, Ashwathanarayana,Jacob, Litwin,Patra, Alakananda,George, Agnes,Philip, Reji,Kumar, Sandeep
, p. 128 - 135 (2018/08/07)
Herein, we have reported the alkyl and alkoxy phenylacetylene containing phenazine fused triphenylene discotic liquid crystals (DLCs) which are obtained by the condensation reaction of triphenylene-1,2-diquinone with 1,2-diamino-4,5-dibromobenzene, followed by Sonogashira C–C coupling reaction with 4-alkyl-phenylacetylene or 4-alkoxy-phenylacetylene. Six novel derivatives were synthesized and evaluated for their thermal and optical properties. They show a broad range of hexagonal columnar phase and retain their mesophase up to room temperature upon cooling from the isotropic liquid. Thermotropic liquid crystalline properties of all the compounds were studied by polarised optical microscopy (POM), differential scanning calorimetry (DSC). The self-assembly of mesophase structure was investigated by X-ray diffraction (XRD) studies. Thermogravimetric analysis of all the mesogens shows good thermal stability over a broad temperature range. The photophysical properties of newly synthesized compounds were measured using UV–Vis absorption and photoluminescence emission spectroscopy in anhydrous chloroform solvent. The π-extended conjugation in these mesogens exhibit strong absorption bands falling around 270–487 nm and corresponding emission band at 657–663 nm respectively. The high delocalization of π– electrons in extended discotic mesogens show high nonlinear optical properties when measured under excitation by nanosecond laser pulses at 532 nm. These materials may find distinctive applications in the semiconducting devices.
Quinolines by three-component reaction: Synthesis and photophysical studies
Sales, Eric S.,Schneider, Juliana M. F. M.,Santos, Marcos J. L.,Bortoluzzi, Adailton J.,Cardoso, Daniel R.,Santos, Willy G.,Merlo, Aloir A.
, p. 562 - 571 (2015/03/14)
The synthesis of five quinolines 8-octyloxy-4-[4-(octyloxy)phenyl]quinoline and 6-alkoxy- 2-(4-alkoxyphenyl)-4-[(4-octyloxy)aryl]quinolines are described by three-component coupling reaction mediated by Lewis acid FeCl3 and Yb(OTf)3. 4-n-octyloxybenzaldehyde, anisaldehyde, 4-n-octyloxyaniline p-anisidine, and 1-ethynyl-4-heptyloxybenzene, 1-ethynyl-4-octyloxybenzene and 2-ethynyl-6-heptyloxynaphthalene are the reagents in this protocol. A Yb3+ catalyst resulted in higher yields of quinolines than Fe3+. Polarizing optical microscopy (POM) revealed that none of the quinolines were liquid crystals, even the more anisotropic. UV-Vis measurements of one of the quinolines in polar solvent show two absorption bands at 280 and 350 nm related to π,π?and n,π?transitions. No changes were observed to lower-energy absorption band (ε 4 mol L-1 cm-1) related to n,π?transition. A laser flash photolysis study for one of the quinolines relates a main transient band at 450 nm with a lifetime of 2.6 μs in ethanol, which is completely quenched in the presence of oxygen. This transient band was assigned to triplet-triplet absorption of one of the quinolines, which is semi-oxidised in the presence of phenol. Radiative rate constants have been determined along singlet and triplet excited state energies (3.39 and 3.10 eV, respectively). The chemical structure of one of the quinolines was also unequivocally confirmed by single-crystal X-ray analysis.
3,5-disubstituted isoxazolines as potential molecular kits for liquid-crystalline materials
Tavares, Aline,Schneider, Paulo H.,Merlo, Aloir A.
body text, p. 889 - 897 (2009/07/19)
A collection of 3,5-disubstituted isoxazolines have been synthesized by 1,3-dipolar [3+2] cycloaddition reactions. Some isoxazolines were selected and transformed into liquid crystals. These new liquid crystals exhibit nematic and smectic C mesophases.
