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

Angew Chem Int Ed Engl. 2022 Jan 26;61(5):e202114070. doi: 10.1002/anie.202114070. Epub 2021 Dec 10.

Abstract

Herein we demonstrate that, based on the creation of dynamic nanospaces in solution by highly charged positive coordination cage of [Pd6 (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.

Keywords: Glaser-coupling reactions; alkyne deuteration; biomimetic cage effect; cage compounds; supramolecular catalysis.

Publication types

  • Research Support, Non-U.S. Gov't