The development of intelligent polymeric materials to precisely control the catalytic sites of heterogeneous catalysts and enable highly efficient catalysis of a cascade reaction is of great significance. Here, the utilization of a polymer ionic liquid (PIL) containing two different anions facilitates the preparation of Ru−Pd catalysts with controllable phase transition temperatures and hydrophilic and hydrophobic surfaces. The combined multifunctionality, synergistic effects, micellar effects, aggregation effects, and temperature responsiveness of the nanocatalyst render it suitable for promoting selectively catalyzed Suzuki coupling and asymmetric transfer hydrogenation in water. Above the lower critical solution temperature (LCST) of the catalyst, it catalyzes only the coupling reaction with a high turnover number (TON) of up to 999.0. Below the LCST, the catalyst catalyzes only the asymmetric transfer hydrogenation with good catalytic activity and enantioselectivity. It is important that the catalyst can be simply and effectively recovered and recycled at least 10 times without significant loss of catalytic activity and enantioselectivity. This study also highlights the superiority of multifunctional heterogeneous catalysts based on PILs, which not only overcome limitations associated with low activity of heterogeneous catalysts but also realize selective reactions according to a temperature change, thereby improving the reactivity and enantioselectivity in multiple organic transformations.

The development of heterogeneous chiral metal catalysts which maintain efficiency and stability in the aqueous phase is significant for applications in many industries. On the basis of a series of polymer ionic liquids (PILs) that contain coexisting Cl– and [NTf2]− anions, the stable heterogeneous chiral Ru catalysts with controllable hydrophobic surface were successfully prepared. PIL-functionalized structure ensured that the catalysts could be well dispersed as micelles in a pure water medium, and enhance the adsorption of organic substrate, thereby significantly improving the reactivity in water. The catalyst successfully catalyzed the asymmetric hydrogenation transfer reaction of alkyl ketones in water with high activity and selectivity. Importantly, the catalyst can be easily and efficiently recovered and recycled at least nine times without significant loss of activity and enantioselectivity. This formation of a catalyst from PIL could provide an important approach to the design of environmentally friendly catalysts and the development of green reactions in the water.

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Significant efforts have been devoted to developing immobilized chiral catalysts with high activity, selectivity, and stability.