Search

The preparation of artificial host–guest systems that display dynamic adaptation during guest binding is challenging. Here the authors report a chiral self-assembled tetrahedral cage featuring curved walls that reconfigures stereochemically to fit fullerene guests, regulates corannulene inversion, and enables the determination of co-guest enantiomeric excess by NMR spectroscopy.

The construction of a self-assembled nanocage composed of four metal ions and six antiaromatic walls is demonstrated, and the effect of antiaromaticity on the host–guest properties is investigated.

Interlocked molecules represent some of the most challenging synthetic targets in terms of non-natural products. It has now been demonstrated how a cyclic [3]catenane composed of three mutually interpenetrating rings can be prepared in two stages using a selective imine exchange reaction on a self-assembled triangular precursor.

A topologically non-trivial metallosupramolecular structure is formed by a Pd₄L₄ complex in which interweaving and twisting of the ligands results in both Solomon's Link and figure-of-eight ring motifs. In the solid state, six of these complexes assemble into a hollow spheroid that closely resembles a stellated truncated hexahedron.

In the original Maxwell’s demon thought experiment, a potential gradient of particles between two neighbouring compartments is created without the apparent use of work. Now a functional example of this experiment where material is pumped over centimetres has been reported—o-fluoroazobenzene is transported unidirectionally under light stimulation between two arms of a U-tube across an aqueous layer containing coordination cages.

Synthesizing topologically complex interwoven molecules with high yield remains challenging due to structural preorganization demands. Here face-bridging ligands on metal–organic cage frameworks are shown to enable high-yield synthesis of knotted cages that mechanically trap guests inside, enhancing guest retention and structural robustness.

Synthetic nanocages that can adapt the size and shape of their cavity in response to a given guest have potential applications in various areas, including chemical purification. Now a flexible, pseudo-cubic metal–organic cage has been developed that is able to dynamically expand its cavity from 46% to 154% of its initial volume by flipping its cage faces.

An organic molecule, 5Cz-TRZ, with multiple donor units supports fast reverse intersystem crossing, allowing fabrication of high-performance organic light-emitting diodes.

Two coordination cages have been devised that undergo covalent modification during a cascade of two orthogonal Diels–Alder reactions. This results in increased lipophilicity for the second cage, enabling its phase transfer and separation from the first. The trigger, relay and inhibition features of this cascade system mimic key aspects of natural post-translational modification cascades.

Controlling the self-assembly of large coordination cages is challenging owing to entropic costs and difficulties in error correction. Now an array of large cages prepared by the rational design of alterations that allow for the tuning of the dihedral angle between pentagonal subunits is reported.

The enantioselective functionalization of C₆₀ is highly challenging, typically requiring complex chiral tethers or demanding chromatography. Fullerenes have now been shown to undergo Diels–Alder reactions in a chemo-, regio- and enantio-selective fashion through confinement within an enantiopure metal–organic cage functionalized with a chiral formylpyridine group.

This Review discusses recent progress in the uses, challenges and future prospects for separations using metal–organic cages. Precise control over the size, shape and functionalization of these cages enables their application for separations required in petroleum, pharmaceuticals, mining and life sciences.