Porous cross-linked polymer copper and iridium catalyzed the synthesis of quinoxalines and functionalized ketones under solvent-free conditions

The development of highly active and efficient ligands is recognized to be crucial for the catalytic applications of coordination polymers under specific conditions, such as solvent-free or in water. A new type of porous cross-linked polymer-containing triazole-skeleton was designed, and the resulting iridium and copper composites were synthesized, fully characterized and exhibited high catalytic activity in the synthesis of quinoxaline derivatives and functionalized ketones under solvent-free conditions. In this methodology, triazole played the special “X-factor” (the designed catalyst exhibits a higher stability for triazole molecule possessing nitrogen σ-donor and lower LUMO aromatic antibonding orbitals, and therefore enhances metal back-bonding of the catalysts) for the highly active iridium and copper composites. Moreover, porous cross-linked polymer-based composites could be recovered and reused for at least five times and mechanism investigations were also carried out to better study these transformations.