Evaluation of Electron-Deficient Phosphine Ligands for Direct Arylation of Heterocycles
作者:Olivier René、Keith Fagnou
DOI:10.1002/adsc.201000397
日期:2010.9.10
New electron‐deficient biarylphosphine ligands were studied and proved to be efficient for the directarylation 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
Nematic Thiophenes for STN-LCDS and Flexoelectric LCDS
作者:Kevin Bartle、Neil Campbell、Warren L. Duffy、Stephen M. Kelly、Vicki Minter、Mary O'Neill、Rachel P. Tuffin
DOI:10.1080/10587250108025061
日期:2001.8
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.