Induced-fit self-assembly using a pyridinium-based dynamic macrocyclic ligand gives rise to a new water-soluble adaptive organo-palladium host. Co-encapsulation of both an electron-rich W10O32
4− cluster and toluene derivatives within the redox-active host facilitates efficient and selective C−H photooxidation under mild conditions.
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 (Pd2L2) 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 (W10O32
4−) can template the dominant formation of the Pd2L2 host. Guest-adaptive conformational changes and induced-fit cavity deformation of the Pd2L2 host have been clearly observed in the crystal structures. Moreover, the installation of the electron-rich W10O32
4− cluster within the cationic redox-active host (W10O32⊂Pd2L2) 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.Zum Volltext