16728-49-7Relevant articles and documents
Formation of a New, Strongly Basic Nitrogen Anion by Metal Oxide Modification
Tamura, Masazumi,Kishi, Ryota,Nakayama, Akira,Nakagawa, Yoshinao,Hasegawa, Jun-Ya,Tomishige, Keiichi
, p. 11857 - 11867 (2017/09/08)
Development of new hybrid materials having unique and unprecedented catalytic properties is a challenge for chemists, and heterogeneous-homogeneous hybrid catalysts have attracted much attention because of the preferable and exceptional properties that are highly expected to result from combination of the components. Base catalysts are widely used in organic synthesis as key materials, and a new class of base catalysts has made a large impact from academic and industrial viewpoints. Here, a principle for creating a new strong base by hybridization of homogeneous and heterogeneous components is presented. It is based on the modification of organic compounds with metal oxides by using the acid-base property of metal oxides. Based on kinetic and DFT studies, combination of CeO2 and 2-cyanopyridine drastically enhanced the basicity of 2-cyanopyridine by a factor of about 109 (～9 by pKa (in CH3CN)), and the pKa was estimated to be ～21, which locates it in the superbase category. 2-Cyanopyridine and CeO2 formed a unique adsorption complex via two interaction modes: (i) coordinative interaction between the Ce atom of CeO2 and the N atom of the pyridine ring in 2-cyanopyridine, and (ii) covalent interaction between the surface O atom of CeO2 and the C atom of the CN group in 2-cyanopyridine by addition of the lattice oxygen of CeO2 to the CN group of 2-cyanopyridine. These interactions established a new, strongly basic site of N- over the CeO2 surface.
Aldose epimerization by Ni(II): effect of ether-containig alkylenediamine ligands
Osanai, Shuichi,Inaba, Kiyoshi,Yoshikawa, Sadao
, p. 289 - 295 (2007/10/02)
Several N-substituted ethylenediamine (en) Ni(II) derivatives containing ether linkages were prepared in order to study the effect of ligand structure on C-2 epimerization of aldohexoses.The reagent consisted of a Ni(II)-alkyenediamine derivative in methanol.The presence of ether linkages in the ligand increased the solubilty of the complexes, and resulted in an increase in the rate of epimerization.Epimerization occured rapidly under mild conditions, and the same equilibrium point was reached regardless of whether the reaction was started from glucose or mannose.Among the ligands studied, N,N'-dialkylethylenediamine was the most effective in C-2 epimerization.
