An Organo‐Palladium Host Built from a Dynamic Macrocyclic Ligand: Adaptive Self‐Assembly, Induced‐Fit Guest Binding, and Catalysis
Dan‐Ni Yan, Li‐Xuan Cai, Shao‐Jun Hu, Yanfang Zhou, Li‐Peng Zhou, Qing‐Fu Sun
Abstract
Abstract Artificial hosts with rich conformational dynamics are attractive to supramolecular chemists due to their adaptive guest‐binding properties and enzyme‐like catalytic functions. We report here the adaptive self‐assembly and host‐guest catalysis of a new water‐soluble organo‐palladium host (Pd 2 L 2 ) built from a pyridinium‐bonded macrocyclic ligand (L) and cis ‐blocked palladium corners (Pd). While the direct self‐assembly of L with Pd gives rise to a dynamic mixture of products, both neutral polyaromatic hydrocarbons and an anionic polyoxometalate cluster (W 10 O 32 4− ) can template the dominant formation of the Pd 2 L 2 host. Guest‐adaptive conformational changes and induced‐fit cavity deformation of the Pd 2 L 2 host have been clearly observed in the crystal structures. Moreover, the installation of the electron‐rich W 10 O 32 4− cluster within the cationic redox‐active host (W 10 O 32 ⊂Pd 2 L 2 ) facilitates the efficient and selective C−H photooxidation of toluene derivatives to aldehyde products under mild conditions, thus representing an ideal platform for green supramolecular catalysis.