589-39-9Relevant articles and documents
A cyclometalated Ir(iii)-NHC complex as a recyclable catalyst for acceptorless dehydrogenation of alcohols to carboxylic acids
Borah, Dhrubajit,Das, Pankaj,Saha, Biswajit,Sarma, Bipul
, p. 16866 - 16876 (2020/12/18)
In this work, we have synthesized two new [C, C] cyclometalated Ir(iii)-NHC complexes, [IrCp?(C∧C:NHC)Br](1a,b), [Cp? = pentamethylcyclopentadienyl; NHC = (2-flurobenzyl)-1-(4-methoxyphenyl)-1H-imidazoline-2-ylidene (a); (2-flurobenzyl)-1-(4-formylphenyl)-1H-imidazoline-2-ylidene (b)] via intramolecular C-H bond activation. The molecular structure of complex 1a was determined by X-ray single crystal analysis. The catalytic potentials of the complexes were explored for acceptorless dehydrogenation of alcohols to carboxylic acids with concomitant hydrogen gas evolution. Under similar experimental conditions, complex 1a was found to be slightly more efficient than complex 1b. Using 0.1 mol% of complex 1a, good-to-excellent yields of carboxylic acids/carboxylates have been obtained for a wide range of alcohols, both aliphatic and aromatic, including those involving heterocycles, in a short reaction time with a low loading of catalyst. Remarkably, our method can produce benzoic acid from benzyl alcohol on a gram scale with a catalyst-to-substrate ratio as low as 1?:?5000 and exhibit a TON of 4550. Furthermore, the catalyst could be recycled at least three times without losing its activity. A mechanism has been proposed based on controlled experiments and in situ NMR study.
The hydroxide-promoted catalytic hydrodefluorination of fluorocarbons by ruthenium in aqueous media
Konnick, Michael M.,Bischof, Steven M.,Periana, Roy A.,Hashiguchi, Brian G.
, p. 632 - 636 (2013/05/09)
A ruthenium complex ligated by the non-innocent protic ligand 2,6-imidizoylpyridine (IPI) in aqueous potassium hydroxide media is shown to be a suitable catalyst for the C-F bond activation and subsequent hydrodefluorination (and hydrogenolysis) of a model fluorocarbon. Furthermore, the conversion of C-F bonds was enhanced upon increasing the concentration of potassium hydroxide [KOH]. A simple, non-ligated heterogeneous analogue derived from ruthenium(III) trichloride trihydrate dissolved in aqueous potassium hydroxide is shown to be an even more active catalyst, capable of hydrodefluorination of aryl fluorocarbons at room temperature and alkyl fluorocarbons under more forcing conditions. Copyright
