Coordination cage with structural “defects” and open metal sites catalyzes selective oxidation of primary alcohols

Coordination cages with intrinsic enzyme-like activity are a class of promising catalysts for improving the efficiency of organic reactions.We present herein a viable strategy to conveniently construct multimetallic active sites into a coordination cage via self-assembly of a pre-formed sulfonylcalix[4]arene-based tetranuclear copper(II)precursor and an amino-functionalized dicarboxylate linker.The cage exhibits a“defective”,partially open cylindrical structure and features coordinatively labile dimetallic Cu(II)sites.Modulated by this unique inner cavity environment,promising catalytic activity toward selective oxidation of primary alcohols to carboxylic acids at room temperature is achieved.Mechanistic studies reveal that the coordinatively labile dimetallic Cu(II)sites can efficiently capture and activate the substrate and oxidant to catalyze the reaction,while the confined nano-cavity environment modulates substrate binding and enhances the catalytic turnover.This study provides a new approach to designing biomimetic multifunctional coordination cages and environmentally friendly supramolecular catalysts.

Precise Assembly and Supramolecular Catalysis of Tetragonal-and Trigonal-Elongated Octahedral Coordination Containers

The construction of distorted or irregular coordination polyhedrons with specific shapes and functionalities is highly challenging.Here,we demonstrate a viable strategy for attaining a severely distorted octahedral coordination container through precise geometrical manipulation of its nanocavity along the C_(3) or C4 axis to turn on its supramolecular catalysis.We constructed a tetragonal-elongated octahedral coordination container utilizing sulfonylcalix[4]arene-capped Co4 units as six vertexes and tetragonalelongated from single-arm lengthened 5-[(4-carboxybenzyl)amino]isophthalate(L)as eight triangular faces.Through the concomitant introduction of C_(3)-symmetry cyclohexane-1,3,5-tricarboxylate as a secondary linker to construct two equilateral triangular base surfaces and L to build six isosceles triangular side planes,trigonal antiprismatic architecture(trigonal-elongated octahedron)was attained.The elongated octahedral containers exhibited distinctly higher binding capacity and stronger binding affinity toward reaction substrates than that of regular octahedral containers;thus,promoting geometry-dependent catalytic reactivity.Our geometrical manipulation strategy provides a viable approach for the convenient design of metal–organic materials with specific functionalities.