title: Guest encapsulation and self-assembly of molecular capsules in polar solvents via multiple ionic interactions.
abstract: Herein we report the formation and characterization of a novel type of capsules resulting from the self-association between oppositely charged complementary building blocks in MeOH/H2O. The assembly is based on the interaction between tetraamidinium calix[4]arenes 1a-d and tetrasulfonato calix[4]arene 2. Evidence for the formation of the expected 1:1 assemblies is provided by proton NMR, ESI-MS, and ITC. The association process is fast on the NMR time scale and strongly entropy driven, with association constants in the range of 10(6) M-1. The system 1a.2 shows binding affinity toward acetylcholine, tetramethylammonium, and N-methylquinuclidinium cations.
authors.affiliation: Laboratory of Supramolecular Chemistry and Technology, MESA+ Research Institute, University of Twente P.O. Box 217, 7500 AE Enschede, The Netherlands.
authors.forename: Francesca
authors.initials: F
authors.lastname: Corbellini
authors.forename: Roberto
authors.initials: R
authors.lastname: Fiammengo
authors.forename: Peter
authors.initials: P
authors.lastname: Timmerman
authors.forename: Mercedes
authors.initials: M
authors.lastname: Crego-Calama
authors.forename: Kees
authors.initials: K
authors.lastname: Versluis
authors.forename: Albert J R
authors.initials: AJ
authors.lastname: Heck
authors.forename: Ingrid
authors.initials: I
authors.lastname: Luyten
authors.forename: David N
authors.initials: DN
authors.lastname: Reinhoudt