Development of a Tethered Palladium–BODIPY Dual Catalyst for Enhanced Photo- and Thermally Activated Catalysis, and for Promoting Sequential Reactivity

Abstract

In recent years there has been a growing interest in merging different types of catalysis to create new multistep catalytic processes. However, the majority of reported dual catalysis strategies use a mixture of individual catalysts, with limited reports of dual catalysis reactions where the different catalysts are combined in a single compound. This work reports the synthesis of a tethered palladium-BODIPY dual catalyst to enable increased synergistic interactions between the catalytic centres. Detailed analysis, including single crystal X-ray crystallography, absorption, fluorescence, and phosphorescence measurements, and kinetic analyses to determine singlet oxygen quantum yields, confirm that chemical tethering results in a significant increase in the photocatalytic potential of the palladium-BODIPY dual catalyst, relative to the parent BODIPY chromophore. Interestingly, the palladium-BODIPY complex also exhibited rare long-lived room temperature phosphorescence. Catalytic applications of the palladium-BODIPY dual catalyst indicate that chemical tethering increases the reactivity of the catalytic centres for both photocatalytic oxidation of thioanisole and palladium catalysed Suzuki–Miyaura cross coupling, highlighting that enhancements in both photo and thermally activated catalysis can be achieved on chemical tethering. In addition, the dual catalytic potential of the palladium-BODIPY catalyst was demonstrated using a representative sequential photocatalytic oxidation–cross coupling reaction.