The Mechanochemistry of Carboranes

Angew Chem Int Ed Engl. 2022 Jun 20;61(25):e202203169. doi: 10.1002/anie.202203169. Epub 2022 Apr 21.

Abstract

We developed o-carborane as a new mechanophore by showing that the o-carborane cluster is the preferred scission site in chain-centered polymers through ultrasonication mechanochemistry. Mechanistic studies are consistent with a predominately homolytic mechanism of chain scission. The mechanically generated monocarbaborane fragments are highly reactive toward alcohol nucleophiles. By contrast, carborane with a different regiochemistry (m-carborane) maintained its high mechanical stability. DFT simulations provide insights into the origins of carborane's mechanical lability. This fundamental research provides a new stimulus for carborane cage activation.

Keywords: Carborane; CoGEF Calculations; Long Carbon-Carbon Bond; Polymer Mechanochemistry; SET-LRP.