Interaction of benzene and 1,2-bis(chloromercurio)tetrafluorobenzene. Supramolecular frameworks based on Hg⋯Cl, Hg⋯F, Hg⋯π and π–π interactions

Abstract

The crystallization of 1,2-bis(chloromercurio)tetrafluorobenzene (1) from a mixture of THF and benzene yields 1·THF·0.5C₆H₆ (2), which contains the Lewis base–Lewis acid adduct 1·μ-THF associated to benzene. When 1 is crystallized from a mixture of propylene oxide and benzene, a compound of composition 1·1.5C₆H₆ (3) is obtained. Both 2 and 3 have been analyzed by solid-state ¹³C CP/MAS NMR spectroscopy and their structures have been investigated by X-ray crystallography. The solid state structure of 2 is that of a framework wherein layers of 1·μ-THF are linked by pillars of sandwiched benzene molecules. The cohesion of this framework results from the presence of intermolecular Hg⋯Cl interactions as well as arene-1,2-bis(chloromercurio)tetrafluorobenzene π–π stacking interactions. The crystal structure of 3 reveals the existence of parallel polymeric chains of 1 embedded in a benzene matrix in which the benzene molecules adopt an edge-to-face arrangement. The polymeric chains of 1 are formed by Hg⋯Cl and Hg⋯F interactions that link the monomers. Finally, part of the benzene molecules in 3 interacts with molecules of 1 by Hg⋯π rather than π–π stacking interactions.