Exceptionally high turnover frequencies recorded for a new chitosan-based palladium(II) catalyst

•A new cross-linked chitosan was obtained using 2,2′-pyridil as a cross-linking agent.•2,2′-Pyridil cross-linked chitosan was used as support for palladium catalyst.•The catalyst yielded excellent TONs of up to 20,000 and TOFs of up to 240,964.

To be industrially feasible, and applicable in synthesis of fine chemicals, a catalyst has to possess high turnover number (TON) and turnover frequency (TOF). In this study, a new cross-linked chitosan derivative was synthesized by using 2,2′-pyridil as a cross-linking agent. 2,2′-Pyridil cross-linked chitosan was used to as a support material for palladium catalyst. Chitosan-pyridil-based Pd(II) catalyst was tested in the microwave-assisted synthesis of biaryls via Suzuki coupling reactions. The catalyst yielded remarkable TONs of up to 20,000 and TOFs of up to 240,964 by using very low catalyst loading (5 × 10−3% mol) in a short reaction time (5 min). The catalyst also showed a better recyclability.

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