A new, deep quinoxaline-based cavitand receptor for the complexation of benzene

We report the synthesis of a new macrocyclic receptor, namely 2,8,14,20-tetra-hexyl-4,24:6,10:12,16:18,22-O,O'-tetra-kis-[2,3-di-hydro-[1,4]dioxino[2,3-g]quinoxalin-7,8-di-yl]resorcin[4]arene, DeepQxCav, obtained by the addition of ethyl-ene glycol di-tosyl-ate to an octa-hydroxy quinoxaline cavitand. A 1:1 supra-molecular complex of this cavitand with benzene has been obtained and analysed through X-ray diffraction analysis. The complex, of general formula C₉₂H₈₈O₁₆N₈·C₆H₆, crystallizes in the space group C2/c, with the cavitand host located about a twofold rotation axis. The benzene guest, which is held inside the cavity by C-H⋯π inter-actions and dispersion forces, is disordered over two equivalent sites, one in a general position and one lying on a twofold axis. The crystal structure features C-H⋯O hydrogen bonds and C-H⋯π inter-actions involving the alkyl chains, the aromatic rings, and the O atoms of the dioxane moiety of the resorcinarene scaffold. The crystal studied was refined as a two-component twin.