A Porous and Stable Porphyrin Metal-Organic Framework as an Efficient Catalyst towards Visible-Light-Mediated Aerobic Cross-Dehydrogenative-Coupling Reactions

Porphyrin metal-organic frameworks (PMOFs) are emerging as heterogeneous photocatalysts owing to the well-designed frameworks incorporated with powerful light-harvesting porphyrin chromophores. The porous and stable framework Ir-PCN-224 (which is also denoted as Ir-PMOF-1), which has been prepared by the self-assembly of Ir(TCPP)Cl (TCPP=tetrakis(4-carboxyphenyl)porphyrin) and ZrCl4, is reported herein to be efficient for the aerobic cross-dehydrogenative carbon-phosphorus coupling reaction, giving rise to a high turn-over number (TON) of up to 17200 under visible light irradiation (lambda >= 420 nm). Electron paramagnetic resonance (EPR) experiments disclose that the active species might be the superoxide radical anion (O-2(.-)). Additionally, the intermediate imine cation has been detected by high-resolution mass spectrometry (HRMS).