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Chlorination of arenes via the degradation of toxic chlorophenols

Paul Joseph Dyson, Mingyang Liu, Xuemei Yang

Aryl chlorides are among the most versatile synthetic precursors, and yet inexpensive and benign chlorination techniques to produce them are underdeveloped. We propose a process to generate aryl chlorides by chloro-group transfer from chlorophenol pollutants to arenes during their mineralization, catalyzed by Cu(NO3)2/NaNO3 under aerobic conditions. A wide range of arene substrates have been chlorinated using this process. Mechanistic studies show that the Cu catalyst acts in cooperation with NOx species generated from the decomposition of NaNO3 to regulate the formation of chlorine radicals that mediate the chlorination of arenes together with the mineralization of chlorophenol. The selective formation of aryl chlorides with the concomitant degradation of toxic chlorophenol pollutants represents a new approach in environmental pollutant detoxication. A reduction in the use of traditional chlorination reagents provides another (indirect) benefit of this procedure.

2022

Nitrile-functionalized pyrrolidinium ionic liquids as solvents for cross-coupling reactions involving in situ generated nanoparticle catalyst reservoirs

Paul Joseph Dyson, Rosario Scopelliti, Zhaofu Fei, Christian Hartinger, Yuehui Li, Xuemei Yang, Ilaria Biondi, Yugang Cui, Manish Chaubey, Cinzia Chiappe

Nitrile-functionalized pyrrolidinium-based ionic liqs. were prepd. and characterized by spectroscopic methods and x-ray crystallog. The application of these new ionic liqs. as reaction media for Suzuki and Stille C-C cross-coupling reactions was studied and compared with related imidazolium and pyridinium systems (including those with and without nitrile functionalities). The nature of the ionic liq. strongly influences the catalyzed reaction and it would appear that, in addn. to the nitrile group, the strength of anion-cation pairing in the ionic liq. and the viscosity of the ionic liq. play crit. roles. Nanoparticles are also detected following catalysis and their role, and the influence of the ionic liq. on them, is assessed. The ability to use the nitrile-functionalized pyrrolidinium-based ionic liqs. dild. in other (nonfunctionalized) ionic liqs. is also described.

Royal Society of Chemistry2010

An Internal Fluorescent Probe Based on Anthracene to Evaluate Cation-Anion Interactions in Imidazolium Salts

Paul Joseph Dyson, Rosario Scopelliti, Zhaofu Fei, Christian Hartinger, Wee Han Ang, Xuemei Yang

A series of fluorescent imidazolium-based salts contg. the cation [AnCH2MeIm]+ (in which An=anthracene and Im=the imidazolium cation) with Cl-, BF4-, PF6-, SO3CF3-, [N(CN)2]-, [N(SO2CF3)2]-, or PhBF3- anions have been prepd. and characterized. X-ray diffraction anal. of four of the salts reveals a no. of C-H•••X-type (X = O, N, F) hydrogen bonds between the hydrogen atoms from the imidazolium ring and in some cases from the anthracene ring with the electroneg. atoms of the anions. Addnl., C-H•••π interactions can be found in all the salts analyzed by X-ray diffraction, whereas π-π stacking is obsd. only in the salt contg. the phenyltrifluoroborate anion. Fluorescence emission anal. in acetonitrile shows that the fluorescence of these salts varies significantly according to the nature of the anion, and correlates to the extent of ion pairing present in soln. Photodimerization of these salts was obsd., and in one case a dimer has been isolated and characterized by X-ray crystallog.

2010