The Ionic Palladium Porphyrin as a Highly Efficient and Recyclable Catalyst for Heck Reaction in Ionic Liquid Solution Under Aerobic Conditions

The ionic palladium porphyrin featured with pyridinium tags at four meso-positions, palladium tetrakis-(N-methyl-4-pyridinium)-porphyrin iodide ([Pd(II)TMPy)P][I]4 (3), embedded in the similar structured ionic liquid of N-butyl pyridinium tetrafluoroborate ([Bpy]BF4) was found to be a highly efficient and recyclable catalytic system for the Heck cross-coupling of iodobenzene (derivatives) and ethyl acylate, with high turnover frequency of 56,000 h−1 under aerobic conditions. The active charge transfer transition occurred in 3-[Bpy]BF4 system during the Heck reaction could account for the efficiency in the catalytic coupling, which was observed in the UV–visible spectra.