19961-27-4Relevant articles and documents
Dynamic Ureas with Fast and pH-Independent Hydrolytic Kinetics
Cai, Kaimin,Ying, Hanze,Cheng, Jianjun
supporting information, p. 7345 - 7348 (2018/06/11)
Low cost, high performance hydrolysable polymers are of great importance in biomedical applications and materials industries. While many applications require materials to have a degradation profile insensitive to external pH to achieve consistent release profiles under varying conditions, hydrolysable chemistry techniques developed so far have pH-dependent hydrolytic kinetics. This work reports the design and synthesis of a new type of hydrolysable polymer that has identical hydrolysis kinetics from pH 3 to 11. The unprecedented pH independent hydrolytic kinetics of the aryl ureas were shown to be related to the dynamic bond dissociation controlled hydrolysis mechanism; the resulting hindered poly(aryl urea) can be degraded with a hydrolysis half-life of 10 min in solution. More importantly, these fast degradable hindered aromatic polyureas can be easily prepared by addition polymerization from commercially available monomers and are resistant to hydrolysis in solid form for months under ambient storage conditions. The combined features of good stability in solid state and fast hydrolysis at various pH values is unprecedented in polyurea material, and will have implications for materials design and applications, such as sacrificial coatings and biomaterials.
Deciphering ligands' interaction with Cu and Cu2O nanocrystal surfaces by NMR solution tools
Glaria, Arnaud,Cure, J??r??my,Piettre, Kilian,Coppel, Yannick,Turrin, C??dric-Olivier,Chaudret, Bruno,Fau, Pierre
supporting information, p. 1169 - 1178 (2015/03/05)
The hydrogenolysis of [Cu2{(iPrN)2(CCH3)}2] in the presence of hexadecylamine (HDA) or tetradecylphosphonic acid (TDPA) in toluene leads to 6-9 nm copper nanocrystals. Solution NMR spectroscopy has been used to describe the nanoparticle surface chemistry during the dynamic phenomenon of air oxidation. The ligands are organized as multilayered shells around the nanoparticles. The shell of ligands is controlled by both their intermolecular interactions and their bonding strength on the nanocrystals. Under ambient atmosphere, the oxidation rate of colloidal copper nanocrystals closely relies on the chemical nature of the employed ligands (base or acid). Primary amine molecules behave as soft ligands for Cu atoms, but are even more strongly coordinated on surface CuI sites, thus allowing a very efficient corrosion protection of the copper core. On the contrary, the TDPA ligands lead to a rapid oxidation rate of Cu nanoparticles and eventually to the re-dissolution of CuII species at the expense of the nanocrystals.
PROCESS FOR PREPARING UNSYMMETRIC SECONDARY TERT-BUTYLAMINES IN THE LIQUID PHASE
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Page/Page column 5-6, (2011/10/19)
The present application relates to a process for preparing unsymmetric secondary tert-butylamines which, as well as the tert-butyl radical, also comprise an alkyl, cycloalkyl or benzyl radical. They are prepared by reacting corresponding aldehydes with tert-butylamine and hydrogen in the presence of hydrogenation catalysts (reductive amination) in the liquid phase.
