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

Abstract

We report the synthesis of a new macrocyclic receptor, namely 2,8,14,20-tetrahexyl-4,24:6,10:12,16:18,22-O,O′-tetrakis[2,3-dihydro-[1,4]dioxino[2,3-g]quinoxalin-7,8-diyl]resorcin[4]arene, DeepQxCav, obtained by the addition of ethylene glycol ditosylate to an octahydroxy quinoxaline cavitand. A 1:1 supramolecular 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 interactions 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 interactions 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.

Keywords

• crystal structure
• quinoxaline cavitands
• inclusion compounds
• benzene