title: Counterion-dependent proton-driven self-assembly of linear supramolecular oligomers based on amino-calix[5]arene building blocks.
abstract: Self-assembly of a calix[5]arene bearing a 12-aminododecyl pendant group on the lower rim into supramolecular oligomers through intermolecular iterative inclusion events is readily triggered by contact with acid solutions and is reversed to the amino monomer precursor by treatment with a base. 1H NMR data are consistent with the formation of head-to-tail assemblies derived from endo-cavity inclusion of the alkylammonium moiety. Diffusion NMR and light-scattering studies provide evidence for the presence of oligomers in solution and show that different counterions and concentrations result in different oligomer sizes, whereas ESI-MS and SEM investigations, respectively, indicate that self-assembly also takes place in the gas phase and in the solid state. The growth of these supramolecular oligomers is concentration-dependent; however, as a consequence of the saline nature of the monomer, it also shows a distinct counterion-dependence owing to ion-pairing/solvation effects.
authors.affiliation: Dipartimento di Scienze Chimiche, Università di Catania, Viale A. Doria 6, 95125 Catania, Italy.
authors.forename: Sebastiano
authors.initials: S
authors.lastname: Pappalardo
authors.forename: Valentina
authors.initials: V
authors.lastname: Villari
authors.forename: Sarit
authors.initials: S
authors.lastname: Slovak
authors.forename: Yoram
authors.initials: Y
authors.lastname: Cohen
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Gattuso
authors.forename: Anna
authors.initials: A
authors.lastname: Notti
authors.forename: Andrea
authors.initials: A
authors.lastname: Pappalardo
authors.forename: Ilenia
authors.initials: I
authors.lastname: Pisagatti
authors.forename: Melchiorre F
authors.initials: MF
authors.lastname: Parisi