2,6-Dibenzhydryl-N-(2-aryliminoacenaphthylenylidene)-4-chlorobenzenamino-palladium dichlorides: Synthesis, characterization, and use as catalysts in the Heck-reaction

A series of 2,6-dibenzhydryl-N-(2-aryliminoacenaphthylenylidene)-4- chlorobenzenaminopalladium(II) chloride complexes (C1–C6) were prepared and fully characterized by FT-IR and NMR spectroscopy, and by elemental analysis. The molecular structures of representative complexes C2 and C6 were confirmed as square planar at the palladium center by single crystal X-Ray diffraction. All palladium complexes exhibited good activity in the Heck cross-coupling reaction with conversions greater than 90%. Catalytic activity trends were attributed to differences in the solubility of the pre-catalysts; palladium complexes bearing more soluble alkyl-substituents performed with higher catalytic activities.

Graphical abstract2,6-Dibenzhydryl-N-(2-aryliminoacenaphthylenylidene)-4-chlorobenzenamino- palladium(II) dichlorides (C1–C6) were prepared and fully characterized. All palladium complexes exhibited good activities in the Heck cross-coupling reaction with conversions higher than 90%.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Unsymmetrical N,N-bisdentate palladium dichloride. ► Highly thermo-stable palladium catalyst. ► Effective Heck reaction. ► Enhanced solubility and activity of catalyst. ► Bulky ligands for better thermo-stability.