Creating Dynamic Nanospaces in Solution by Cationic Cages as Multirole Catalytic Platform for Unconventional C(sp)-H Activation Beyond Enzyme Mimics

Herein we demonstrate that, based on the creation of dynamic nanospaces in solution by highly charged positive coordination cage of [Pd-6(RuL3)(8)](28+), multirole and multi-way cage-confined catalysis is accomplishable for versatile functions and anomalous reactivities with the aid of the biomimetic cage effect. The high cationic-host charges drive partial deprotonation of 24 imidazole-NHs on cage sphere alike imidazole-residuals in proteins, generating amphoteric heterogeneity in solution to enforce effective cavity-basicity against solution-acidity. Synergistic actions arisen from cage hydrophobicity, host-guest electrostatic interactions and imidazole-N coordination facilitate C(sp)-H activation and carbanionic intermediate stabilization of terminal alkynes to achieve unusual H/D-exchange and Glaser coupling under acidic conditions, and enable phase transfers of water-insoluble substrates/products/co-catalysts to make immiscible-phase and bi-phase catalysis feasible, thus providing a useful catalytic protocol to combine merits from homogeneous, heterogeneous, enzymatic and phase transfer catalysis.

Automated summary

In this study, we demonstrate the accomplishment of multirole and multi-way cage-confined catalysis by creating dynamic nanospaces in solution using highly charged positive coordination cage of [Pd-6(RuL3)(8)](28+). The biomimetic cage effect enables versatile functions and anomalous reactivities, and the amphoteric heterogeneity generated by partial deprotonation of imidazole-NHs on cage sphere enhances cavity-basicity against solution-acidity. The synergistic actions of cage hydrophobicity, host-guest electrostatic interactions, and imidazole-N coordination facilitate various catalytic reactions and phase transfers, providing a useful catalytic protocol that combines the merits of different types of catalysis.