Water-soluble cis-[(NHC)PdBr2(TPPTS)] catalysts and their applications in Suzuki–Miyaura coupling of aryl chlorides

New palladium(II) complexes (2), bearing NHC/TPPTS ligands, (NHC = benzimidazol-2-ylidene; TPPTS = triphenylphosphine-3,3′,3″-trisulfonic acid trisodium salt) have been prepared and characterized by elemental analyses and spectroscopic methods. Their ability to catalyze the Suzuki–Miyaura reaction in neat water has been studied at 100 °C. Very high activities have been observed in the coupling of phenylboronic acid with aryl chlorides in the presence of 1% of the catalyst. We have compared the electronic properties of cis-[PdBr2(NHC)(TPPTS)] with the related complexes, [PdX2(NHC)]2 and [trans-PdBr2(NHC)(pdca)] (pdca = pyridine-2,6-dicarboxyic acid) (3) via three different techniques: cyclic voltammetry, thermogravimetric analysis and 13C NMR spectroscopy.

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (113 K)Download as PowerPoint slideHighlights► Water soluble complexes were prepared. ► These complexes were active in the Suzuki cross-coupling reactions. ► Makes the catalyst reusable. ► This process is ecologically and economically acceptable.