Hypercrosslinked Polymer Platform-Anchored Single-Site Heterogeneous Pd–NHC Catalysts for Diverse C–H Functionalization

We demonstrate a new class of hypercrosslinked polymer (HCP) platform-anchored single-site heterogenized Pd–NHC catalysts for multipurpose C–H functionalization reactions. This new class is represented by a set of three catalysts, viz., HCP-B- Me NHC-Pd, HCP-B- Bn NHC-Pd, and HCP-TPM- Me NHC-Pd, having a variation on the structural feature of the anchoring polymeric platform. All three catalysts were fully characterized via diverse solid-state characterization and analytical techniques such as X-ray photoelectron spectroscopy, 13C cross-polarization magic-angle-spinning nuclear magnetic resonance, field-emission scanning electron microscopy, energy-dispersive X-ray analysis, thermogravimetric analysis, and inductively coupled plasma–optical emission spectrometry. Three types of regularly practiced and very useful C–H functionalization reactions, viz., C–H halogenation, acetoxylation, and arylation, are tested with the new catalysts and found to be highly compatible and successful. With the HCP-TPM- Me NHC-Pd catalyst, up to 85, 75, and 70% yields of the functionalized products were achieved for the halogenation, acetoxylation, and arylation reactions, respectively. Demanding attributes such as enhanced activity, heterogeneity, and recyclability are offered by this new system, making it a promising candidate in the field of heterogeneous C–H functionalization, where only a few efficient catalysts are available.