Water-soluble SNS cationic palladium(II) complexes and their Suzuki–Miyaura cross-coupling reactions in aqueous medium

Abstract

Unlike their SCS analogues, SNS pincer complexes are poorly studied for their use in coupling reactions. Accordingly, a series of water soluble cationic Pd(II) SNS pincer complexes have been successfully synthesised and investigated in detail for their catalytic activity in Suzuki–Miyaura coupling reactions. By using only 0.5 mol % loading of the complexes, the coupling of inactivated aryl bromides and activated aryl chlorides with various boronic acids in water was achieved in excellent yields and the catalysts were found to be reusable for three cycles without a significant loss of activity. The investigation of the mechanism of the reaction revealed that a Pd(II) to Pd(IV) route is the more likely pathway which was further supported by computational studies.

Efficient construction of C–C bonds from aryl halides/aryl esters with arylboronic acids catalysed by palladium(II) thiourea complexes

“…Herein, we propose a plausible reaction mechanism for the SMC reaction according to literature reports . In general, the stronger binding nature of chelating anionic ligands having heteroatoms or carbon with palladium centre prevents bond cleavage during the catalytic process.…”

Molecular docking-assisted investigation of Pd(II) complexes carrying “SNS” pincer-type pyridine-thioether ligand as potential drug candidates against COVID-19

“…Unfortunately, single-crystal X-ray analysis could not be performed because the structures could not be obtained as single crystals despite crystallization efforts. A four-coordinated square-plane structure is proposed for Pd(II) complexes [ [65] , [66] , [67] , [68] ].…”

Molecular Organosulphur, Organoselenium and Organotellurium Complexes as Homogeneous Transition Metal Catalytic Systems for Suzuki Coupling

“…The development of symmetrical (S,N,S) pincer ligand L5 is carried out (Scheme 3) by the treatment 2,6‐bis(chloromethyl)pyridine with in‐situgenerated thiolate in DMF at 70 °C [20] …”