Strong σ-Hole Activation on Icosahedral Carborane Derivatives for a Directional Halide Recognition

Angew Chem Int Ed Engl. 2021 Jan 4;60(1):366-370. doi: 10.1002/anie.202010462. Epub 2020 Oct 29.

Abstract

Crystal engineering based on σ-hole interactions is an emerging approach for realization of new materials with higher complexity. Neutral inorganic clusters derived from 1,2-dicarba-closo-dodecaborane, substituted with -SeMe, -TeMe, and -I moieties on both skeletal carbon vertices are experimentally demonstrated herein as outstanding chalcogen- and halogen-bond donors. In particular, these new molecules strongly interact with halide anions in the solid-state. The halide ions are coordinated by one or two donor groups (μ1 - and μ2 -coordinations), to stabilize a discrete monomer or dimer motifs to 1D supramolecular zig-zag chains. Crucially, the observed chalcogen bond and halogen bond interactions feature remarkably short distances and high directionality. Electrostatic potential calculations further demonstrate the efficiency of the carborane derivatives, with Vs,max being similar or even superior to that of reference organic halogen-bond donors, such as iodopentafluorobenzene.

Keywords: carborane; chalcogen bonding; crystal engineering; halogen bonding; sigma-hole interaction.