475996-53-3Relevant academic research and scientific papers
Synthesis and mesophase behavior of phenylthiophene based amphiphilic molecules
Jing, Shan,Zhang, Ruilin,Dai, Heng,Du, Chao,Cheng, Xiaohong
scheme or table, p. 577 - 584 (2012/06/04)
Novel amphiphilic molecules consisting of a rigid 2-phenylthiophene core, with a polar flexible tri(oxylethylene) moiety attached to the phenyl ring and one or two alkyl chains attached to the thiophene ring at the other side have been synthesized by using Ni(II) and Pd(0) catalyzed coupling reaction as key steps. The tri(oxylethylene) moieties were terminated with hydroxyl group, sodium carboxylate group and lithium carboxylate group respectively. The thermotropic and solvent induced liquid crystalline behavior of these substances was investigated by polarized optical microscopy, differential scanning calorimetry and X-ray diffraction. Thereby the influence of the terminal groups attached to the tri(oxylethylene) moities as well as the influence of the length and the number of the alkyl chains on the mesophase behavior were investigated. The single alkyl chain Na-carboxylate termianted derivatives show smectic A phases, double alkyl chain Na-carboxylate terminated derivatives show a thermo tropic hexagonal columnar mesophase, while columnar mesophases are found in both single and double alkyl chain Li-carbonate terminated derivatives. The model for molecular organization in the hexagonal columnar mesophase is established.
Evaluation of electron-deficient phosphine ligands for direct arylation of heterocycles
Rene, Olivier,Fagnou, Keith
supporting information; experimental part, p. 2116 - 2120 (2010/11/04)
New electron-deficient biarylphosphine ligands were studied and proved to be efficient for the direct arylation of heteroarenes with aryl iodides. The ability of a more electron-deficient palladium centre to accelerate the arylation of heterocycles that remained unreactive with aryl iodides in the past has been validated and these heteroarenes can now be smoothly reacted in the presence of a new electrophilic catalyst. Experimental evidence suggests a viable concerted metalation-deprotonation pathway for the C-H bond cleavage step with an electron-deficient palladium centre.
Nematic 2,5-disubstituted thiophenes
Campbell, Neil L.,Duffy, Warren L.,Thomas, Gareth I.,Wild, Janine H.,Kelly, Stephen M.,Bartle, Kevin,O'Neill, Mary,Minter, Vicky,Tuffin, Rachel P.
, p. 2706 - 2721 (2007/10/03)
A large number of new liquid crystals incorporating the 2,5-disubstituted thiophene ring have been prepared and their mesomorphic behaviour studied in order to systematically investigate the correlation between the molecular structure and mesomorphism of thiophene derivatives with different shapes, polarisability and polarity. As a consequence of these investigations we have prepared a new class of liquid crystals incorporating a 2,5-disubstituted thiophene ring and a conjugated trans-carbon-carbon double bond in the terminal chain. These novel thiophene derivatives are the first liquid crystals incorporating a 2,5-disubstituted thiophene ring to exhibit a nematic phase at room temperature. This enables the flexoelectric coefficients of a bent-shaped molecule to be measured directly and at room temperature for the first time to the authors' knowledge. Many of these new thiophenes exhibit a high birefringence and a high nematic clearing point and are of potential use as components of nematic mixtures in LCDs.
Nematic thiophenes for STN-LCDS and flexoelectric LCDS
Bartle, Kevin,Campbell, Neil,Duffy, Warren L.,Kelly, Stephen M.,Minter, Vicki,O'Neill, Mary,Tuffin, Rachel P.
, p. 881 - 888 (2007/10/03)
We report anew class of liquid crystals incorporating a 2,5-disubstituted thiophene ring and one or two conjugated trans-carbon-carbon double bonds in the terminal chain for use as components of nematic mixtures for TN-LCDs and STN-LCDs. The combination of these molecular elements contribute towards generating a high birefringence, a high nematic clearing point as well as a low viscosity for these materials. Several of these compounds exhibit a melting point below room temperature. This is the first time a room temperature nematic phase has been reported for phenyl thiophene derivatives. The new thiophene compounds can be used to induce a high birefringence in nematic mixtures for LCDs with short response times.
