title: Halogen bonding molecular capsules.
abstract: Molecular capsules based solely on the interaction of halogen bonding (XB) are presented along with their host-guest binding properties in solution. The first example of a well-defined four-point XB supramolecular system is realized by decorating resorcin[4]arene cavitands with polarized halogen atoms for dimerization with tetra(4-pyridyl) resorcin[4]arene cavitands. NMR binding data for the F, Cl, Br, and I cavitands as the XB donor show association constants (Ka ) of up to 5370 M(-1) (ΔG283 K =-4.85 kcal mol(-1) , for I), even in XB-competitive solvent, such as deuterated benzene/acetone/methanol (70:30:1) at 283 K, where comparable monodentate model systems show no association. The XB capsular geometry is evidenced by two-dimensional HOESY NMR, and the thermodynamic profile shows that capsule formation is enthalpically driven. Either 1,4-dioxane or 1,4-dithiane are encapsulated within each of the two separate cavities within the XB capsule, with of up to Ka =9.0 10(8)  M(-2) (ΔG283 K =-11.6 kcal mol(-1) ).
authors.affiliation: Laboratorium für Organische Chemie, ETH Zurich, Vladimir-Prelog-Weg 3, CH-8093 Zurich (Switzerland).
authors.forename: Oliver
authors.initials: O
authors.lastname: Dumele
authors.affiliation: Laboratorium für Organische Chemie, ETH Zurich, Vladimir-Prelog-Weg 3, CH-8093 Zurich (Switzerland).
authors.forename: Nils
authors.initials: N
authors.lastname: Trapp
authors.affiliation: Laboratorium für Organische Chemie, ETH Zurich, Vladimir-Prelog-Weg 3, CH-8093 Zurich (Switzerland). diederich@org.chem.ethz.ch.
authors.forename: François
authors.initials: F
authors.lastname: Diederich
keywords: X-ray diffraction; halogen bonding; host-guest systems; self-assembly; supramolecular chemistry