Mononuclear palladacycles versus acyclic analogues: a structure and reactivity comparison

The metallocyclic ring in mononuclear iminoisoindoline-based palladacycle [(κ 2 -iminoisoidoline)PdCl(PCy 3 )] (3) can be ring opened by coordination of phosphine to form the trans bis(phosphine) iminoisoindoline-based palladium(II) complex [(η 1 -iminoisoidoline)PdCl(PCy 3 ) 2 ] (4) where the η 1 -iminoisoindoline is coordinated only by an Ar–Pd bond. The ring-opened analogue showed significantly higher coupling activity in Suzuki-Miyaura reactions with aryl chlorides than any iminoisoindoline-based palladacycle studied to date. These results are compared to existing mononuclear palladacycles and reported acyclic analogues.