Synthesis of a molecular tweezer containing pentafluorophenyl groups and investigation of the π-π stacking interaction for a pentafluorophenyl group in a polar organic solvent

A molecular tweezer having two bidentate pentafluorophenyl (C ₆F ₅) groups was synthesized, and the π-π stacking ability of the C ₆F ₅ groups toward benzene derivatives in a polar organic solvent was evaluated. The structure of the molecular tweezer was revealed to be dimeric in the crystalline state by X-ray analysis. Association constants (K _a) between the molecular tweezer and aromatic guests in THF were found to be roughly correlated with the quadrupole moment (Q _zz) of the guests, suggesting that the quadrupole-quadrupole contribution plays a significant role in the π-π interaction even in a polar organic solvent.