30752-20-6Relevant articles and documents
Azo bond formation on metal surfaces
Meng, Xiangzhi,Klaasen, Henning,Viergutz, Lena,Schulze Lammers, Bertram,Witteler, Melanie C.,M?nig, Harry,Amirjalayer, Saeed,Liu, Lacheng,Neugebauer, Johannes,Gao, Hong-Ying,Studer, Armido,Fuchs, Harald
supporting information, p. 1458 - 1464 (2020/12/14)
The formation of azo compounds via redox cross-coupling of nitroarenes and arylamines, challenging in solution phase chemistry, is achieved by on-surface chemistry. Reaction products are analyzed with a cryogenic scanning tunneling microscope (STM) and X-ray photoelectron spectroscopy (XPS). By using well-designed precursors containing both an amino and a nitro functionality, azo polymers are prepared on surface via highly efficient nitro-amino cross-coupling. Experiments conducted on other substrates and surface orientations reveal that the metal surface has a significant effect on the reaction efficiency. The reaction was further found to proceed from partially oxidized/reduced precursors in dimerization reactions, shedding light on the mechanism that was studied by DFT calculations.
New pyridine based liquid crystalline esters with different terminal chains
Karanl?k, Gürkan,Ocak, Hale,Bilgin Eran, Belk?z
, (2019/08/22)
The synthesis, structural and mesomorphic characterization of new pyridine-based methyl esters carrying a n-alkoxy chain or 3,7-Dimethyloctyloxy branched group at terminal have been presented. The liquid crystalline properties of the new pyridine-based calamitic molecules have been investigated by polarized optical microscopy and differential scanning calorimetry. New compounds exhibit enantiotropic smectic A mesophase at a variable mesomorphic range depending on alkoxy chain length and branching at terminal. The presence of a branched terminal group in chiral or racemic form gives rise to a sharply increase in mesomorphic range as well as decrease in crystallization points by preserving mesophase type.
Synthesis and Characterization of a New Series of Paramagnetic Ferroelectric Liquid Crystalline Nitroxide Radicals
Uchida, Yoshiaki,Tamura, Rui,Suzuki, Katsuaki,Takahashi, Hiroki,Aoki, Yoshio,Nohira, Hiroyuki
, p. 89 - 106 (2015/09/01)
A new series of all-organic liquid-crystalline (LC) chiral radical compounds,trans-1-alkoxyphenyl-4-[(4-(4-alkoxyphenyl)-2,5-dimethylpyrrolidine-1-oxy-2-yl)-benzylideneamino]benzenes (1) with various alkyl chains, containing a chiral nitroxide unit in the mesogen core were synthesized and their LC properties were fully characterized. The enantiomerically enriched compounds (2S,5S)-1 showed N, TGBA, SmA and SmC phases, while the racemates (±)-1 exhibited N, SmA and SmC phases. The phase transition behavior and the ferroelectric properties of the SmC phase of (2S,5S)-1 differed from those of previously reported analogues with an ester group as a substitute for the imino group of (2S,5S)-1. Some of the (2S,5S)-1 series showed a temperature-dependent spontaneous polarization PS (θ) inversion. We discuss the origin of this difference in terms of their molecular structures optimized by molecular orbital calculations. The phase transition behavior supports the hypothesis that the large φ, which is defined as the angle between the molecular long axis (one of the principal axes of inertia) and the direction of the dipole moment in each molecule, results in the stabilization of the SmA (SmA) phase.
