Self-assembly of grid and helical hydrogen-bonded arrays incorporating bowl-shaped receptor sites that bind globular molecules

1,2-Dicarbadodecaborane(12) (o-carborane) and bowl-shaped cyclotriveratrylene (CTV) self-assemble through bifurcated C-H_carborane ⋯ (O)₂ hydrogen bonds into infinite arrays with two-dimensional (2D) hexagonal grid or helical chain topologies. The in-built shape-specific receptor sites bind o-carborane or fullerene C₇₀. The structures of two such supramolecular systems in the solid state were established: (o-carborane)₂(CTV) features hydrogenbonded carborane ⋯ CTV hexagonal grids as well as CTV ⋯ carborane host-guest interactions, while a helical hydrogen-bonded carborane ⋯ CTV chain is formed in the quaternary system (C₇₀)(o-carborane)(CTV)(1,2-dichlorobenzene) in addition to CTV ⋯ C₇₀ host-guest interactions. The bifurcated C-H_carborane ⋯ (O)₂ hydrogen bonding interaction common to both these structures was studied on the model system (o-carborane)(1,2-dimethoxybenzene) using ab initio calculations and found to be energetically favoured by 5.48 kcal mol^-1, whereas a B-H_carborane ⋯ (O), bifurcated hydrogen bonding was less favoured at 1.13 kcal mol^-1.