A Bipyridine‐Palladium Derivative as General Pre‐Catalyst for Cross‐Coupling Reactions in Deep Eutectic Solvents

Abstract

A versatile and DES‐compatible bipyridine palladium complex has been developed as a general pre‐catalyst for different cross‐coupling reactions (Hiyama, Suzuki‐Miyaura, Heck‐Mizoroki and Sonogashira) in deep eutectic solvents. Hydrogen bond capacity of the ligand allows to keep the excellent level of results previously obtained in classical organic solvents. Palladium pre‐catalyst showed a high catalytic activity for many cross‐coupling reactions, demonstrating a great versatility and applicability. Also, this methodology employs sustainable solvents as a reaction medium and highlights the potential of DES as alternative solvents in organometallic catalysis. The catalyst and DES were easily and successfully recycled. The formation of PdNPs in DES has been confirmed by TEM and XPS analysis and their role as catalyst by mercury test. The dynamic coordination of bipyridine‐type ligand in the palladium complex formation has been studied via UV/Vis.