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

The crystallization of 1,2-bis(chloromercurio)tetrafluorobenzene (1) from a mixture of THF and benzene yields 1.THF.0.5C(6)H(6) (2), which contains the Lewis base-Lewis acid adduct 1.mu-THF associated to benzene. When 1 is crystallized from a mixture of propylene oxide and benzene, a compound of composition 1 . 1.5C(6)H(6) (3) is obtained. Both 2 and 3 have been analyzed by solid-state C-13 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.mu-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 pi-pi 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 ...pi rather than pi-pi stacking interactions.