454-49-9Relevant articles and documents
Electroanalysis of Neutral Precursors in Protic Ionic Liquids and Synthesis of High-Ionicity Ionic Liquids
Goodwin, Sean E.,Smith, Daniel E.,Gibson, Joshua S.,Jones, Robert G.,Walsh, Darren A.
, p. 8436 - 8446 (2017)
Protic ionic liquids (PILs) are ionic liquids that are formed by transferring protons from Br?nsted acids to Br?nsted bases. While they nominally consist entirely of ions, PILs can often behave as though they contain a significant amount of neutral species (either molecules or ion clusters), and there is currently a lot of interest in determining the degree of "ionicity" of PILs. In this contribution, we describe a simple electroanalytical method for detecting and quantifying residual excess acids in a series of ammonium-based PILs (diethylmethylammonium triflate [dema][TfO], dimethylethylammonium triflate [dmea][TfO], triethylammonium trifluoroacetate [tea][TfAc], and dimethylbutylammonium triflate [dmba][TfO]). Ultra-microelectrode voltammetry reveals that some of the accepted methods for synthesizing PILs can readily result in the formation of nonstoichiometric PILs containing up to 230 mM excess acid. In addition, vacuum purification of PILs is of limited use in cases where nonstoichiometric PILs are formed. Although excess bases can be readily removed from PILs under ambient conditions, excess acids cannot be removed, even under high vacuum. The effects of excess acid on the electrocatalytic oxygen reduction reaction (ORR) in PILs have been studied, and the onset potential of the ORR in [dema][TfO] increases by 0.8 V upon addition of acid to PIL. On the basis of the results of our analyses, we provide some recommendations for the synthesis of highly ionic PILs.
Palladium-Catalyzed Hydride Addition/C-H Bond Activation Cascade: Cycloisomerization of 1,6-Diynes
Rodríguez, José F.,Burton, Katherine I.,Franzoni, Ivan,Petrone, David A.,Scheipers, Ina,Lautens, Mark
supporting information, p. 6915 - 6919 (2018/11/21)
The use of ammonium halide salts as metal hydride precursors in a new Pd-catalyzed cycloisomerization of 1,6-diynes, which affords unexplored silylated 2-azafluorenes, is reported. This cascade process includes the addition of a Pd-hydride species to a π-system, intramolecular carbopalladation, and C(sp2)-H bond activation. A variety of functional groups are tolerated, and the synthetic utility of the resulting products has been demonstrated by a series of derivatizations.
Rapid formation of diphenylmethyl ethers and thioethers using microwave irradiation and protic ionic liquids
Altimari, Jarrad M.,Delaney, Joshua P.,Servinis, Linden,Squire, Jennifer S.,Thornton, Megan T.,Khosa, Simren K.,Long, Benjamin M.,Johnstone, Mark D.,Fleming, Cassandra L.,Pfeffer, Frederick M.,Hickey, Shane M.,Wride, Matthew P.,Ashton, Trent D.,Fox, Bronwyn L.,Byrne, Nolene,Henderson, Luke C.
supporting information; experimental part, p. 2035 - 2039 (2012/07/17)
Using microwave irradiation and protic ionic liquids (pIL) as co-solvent and catalyst for the synthesis of several diphenylmethyl ethers was achieved. The desired ethers were isolated simply by filtration through a silica plug to remove the pIL and proceeded in high yields (60-98%). These reactions were extremely rapid (10-30 min) and occurred under mild conditions (80 °C). This protocol was also successfully applied to the synthesis of thioethers.
