The controllable B–H bond activation of carboranes has long been a compelling challenge. However, as the symmetry of para-carborane places the same charge on all of its ten boron atoms, controlling the regiochemistry of B–H bond activation in these molecules has remained out of reach ever since their discovery. Herein, we describe how to use steric effects to achieve a regioselective process for B–H activation of para-carborane. In this strategy, B­(2,8)–H or B­(2,7)–H activation patterns were achieved by taking advantage of the π–π interactions between pyridine ligands. Interestingly, by employing host–guest interactions in metallacage compounds, B­(2,8)–H bond activation could be avoided and exclusive B­(2,9)–H bond activation can be achieved. Steric hindrance was also found to be beneficial for regioselective B­(2,8)–H bond activation in metallacage species. In this work, we demonstrate that steric effects can be a promising driving force for controllable activation of the B–H bonds of carboranes and open new opportunities in this field.

The specific recognition and separation of alkanes with similar molecular structures and close boiling points face significant scientific challenges and industrial demands. Here, rectangular carborane-based metallacycles were designed to selectively encapsulate n-pentane from n-pentane, iso-pentane, and cyclo-pentane mixtures in a simple-to-operate and more energy-efficient way. Metallacycle 1, bearing 1,2-di(4-pyridyl) ethylene, can selectively separate n-pentane from these three-component mixtures with a purity of 97%. The selectivity is ascribed to the capture of the preferred guest with matching size, C−H•••π interactions, and potential B−H δ− •••H δ+ −C interactions. Besides, the removal of n-pentane gives rise to original guest-free carborane-based metallacycles, which can be recycled without losing performance. Considering the variety of substituted carborane derivatives, metal ions, and organic linkers, these new carborane-based supramolecular coordination complexes (SCCs) may be broadly applicable to other challenging recognition and separation systems with good performance.

In this work, a pincer‐type complex [Cp*Ir‐(SNPh)(SNHPh)(C2B10H9)] (2) was synthesized and its reactivity studied in detail. Interestingly, molecular hydrogen can induce the transformation between the metalloradical [Cp*Ir‐(SNPh)2(C2B10H9)] (5.) and 2. A mixed‐valence complex, [(Cp*Ir)2‐(SNPh)2(C2B10H8)] (7.+), was also synthesized by one‐electron oxidation. Studies show that 7.+ is fully delocalized, possessing a four‐centered‐one‐electron (S‐Ir‐Ir‐S) bonding interaction. DFT calculations were also in good agreement with the experimental results.

Stepwise, multiple B-H bond activation is a major challenge in synthetic chemistry. Herein, we have developed a time-controlled method to monitor the process of B-H bond activation based on a...

Developing novel assembly methods for supramolecular compounds has long been a research challenge. Herein, we describe how to integrate the B–C coupling reaction and “cage walking” process into coordination self-assembly to construct supramolecular cages. In this strategy, dipyridine linkers containing alkynes react with the metallized carborane backbone through B–C coupling and then “cage walking” resulting in metallacages. However, dipyridine linkers without alkynyl groups can form only metallacycles. We can regulate the size of metallacages based on the length of the alkynyl bipyridine linkers. When tridentate-pyridine linkers participate in this reaction, a new type of ravel is formed. The metallization of carboranes, the B–C coupling reaction, and especially the “cage walking” process of carborane cages play a vital role in this reaction. This work provides a promising principle for the synthesis of metallacages and opens up a novel opportunity in the supramolecular field.