820972-37-0Relevant articles and documents
Nitrile-functionalized pyridinium, pyrrolidinium, and piperidinium ionic liquids
Lethesh, Kallidanthiyil Chellappan,Van Hecke, Kristof,Van Meervelt, Luc,Nockemann, Peter,Kirchner, Barbara,Zahn, Stefan,Parac-Vogt, Tatjana N.,Dehaen, Wim,Binnemans, Koen
, p. 8424 - 8438 (2011)
Two series of 1-alkylpyridinium and N-alkyl-N-methylpiperidinium ionic liquids functionalized with a nitrile group at the end of the alkyl chain have been synthesized. Structural modifications include a change of the alkyl spacer length between the nitrile group and the heterocycle of the cationic core, as well as adding methyl or ethyl substituents on different positions of the pyridinium ring. The anions are the bromide and the bis(trifluoromethylsulfonyl) imide ion. All the bis(trifluoromethylsulfonyl)imide salts as well as the bromide salts with a long alkyl spacer were obtained as viscous liquids at room temperature, but some turned out to be supercooled liquids. In addition, pyrrolidinium and piperidinium ionic liquids with two nitrile functions attached to the heterocyclic core have been prepared. The crystal structures of seven pyridinium bis(trifluoromethylsulfonyl)imide salts are reported. Quantum chemical calculations have been performed on model cations and ion pairs with the bis(trifluoromethylsulfonyl)imide anion. A continuum model has been used to take solvation effects into account. These calculations show that the natural partial charge on the nitrogen atom of the nitrile group becomes more negative when the length of the alkyl spacer between the nitrile functional group and the heterocyclic core of the cation is increased. Methyl or methoxy substituents on the pyridinium ring slightly increase the negative charge on the nitrile nitrogen atom due to their electron-donating abilities. The position of the substituent (ortho, meta, or para) has only a very minor effect on the charge of the nitrogen atom. The 15N NMR spectra of the bis(trifluoromethylsulfonyl)imide ionic liquids were recorded with the nitrogen-15 nucleus at its natural abundance. The chemical shift of the 15N nucleus of the nitrile nitrogen atom could be correlated with the calculated negative partial charge on the nitrogen atom. ? 2011 American Chemical Society.
Palladium-catalyzed desulfitative Mizoroki-Heck coupling reactions of sulfonyl chlorides with olefins in a nitrile-functionalized ionic liquid
Dubbaka, Srinivas Reddy,Zhao, Dongbin,Fei, Zhaofu,Volla, Chandra M. Rao,Dyson, Paul J.,Vogel, Pierre
, p. 3155 - 3157 (2008/02/13)
Aryl and alkenyl sulfonyl chlorides can be used in Heck-Mizoroki-type couplings with mono- and disubstituted olefins in a nitrile-functionalized ionic liquid, viz. [C3CNpy] [Tf2N]. Advantages over previously reported methods include: (1) use of a cheap catalyst source, PdCl2, (2) ability to handle the catalyst in air, (3) reduced reaction times, (4) elimination of phase-transfer catalysts due to the high solubility of the inorganic base in the ionic liquid, and (5) facile recycling of the ionic liquid-palladium catalyst. The yields of coupling products remain in the same range as the reactions conducted in organic solvents. Palladium nanoparticles, characterized using transmission electron microscopy, have been identified in the ionic liquid following the Heck-Mizoroki type coupling reactions. Georg Thieme Verlag Stuttgart.
