Highly Stable and Porous Cross-Linked Polymers for Efficient Photocatalysis

Abstract

Porous cross-linked polymers (PCPs) with phosphorescent [Ru(bpy)₃]²⁺ and [Ir(ppy)₂(bpy)]⁺ building blocks were obtained via octacarbonyldicobalt (Co₂(CO)₈)-catalyzed alkyne trimerization reactions. The resultant Ru- and Ir-PCPs exhibited high porosity with specific surface areas of 1348 and 1547 m²/g, respectively. They are thermally stable at up to 350 °C in air and do not dissolve or decompose in all solvents tested, including concentrated hydrochloric acid. The photoactive PCPs were shown to be highly effective, recyclable, and reusable heterogeneous photocatalysts for aza-Henry reactions, α-arylation of bromomalonate, and oxyamination of an aldehyde, with catalytic activities comparable to those of the homogeneous [Ru(bpy)₃]²⁺ and [Ir(ppy)₂(bpy)]⁺ photocatalysts. This work highlights the potential of developing photoactive PCPs as highly stable, molecularly tunable, and recyclable and reusable heterogeneous photocatalysts for a variety of important organic transformations.