title: Thermodynamics of formation of host-guest supramolecular polymers.
abstract: The interactions between three beta-cyclodextrin hosts (having 1-3 binding sites) and two adamantyl guests (having 1-2 binding sites) have been studied by ITC, ROESY, static and dynamic light scattering (SLS and DLS), and AFM and TEM techniques. The enthalpy and free energy values (determined from ITC experiments) evidence that the single interaction between one binding site of the guest and one binding site of the host is independent of the number of binding sites of the interacting species. The average values are deltaH degrees = -26.6 +/- 2.3 kJ mol(-1) and deltaG degrees = -30.4 +/- 3.2 kJ mol(-1), indicating that the process is mainly enthalpy driven. In all cases, the experimental molar ratio (from ITC experiments) agrees with the expected one from the number of binding sites of both the host and guest. The formation of polymer-like entities was demonstrated by SLS, DLS, AFM, and TEM measurements. The structure of polymers is linear when both the host and the guest are ditopic entities and dendritic (or Cayley tree type) when the host and the guest have three and two binding sites, respectively.
authors.affiliation: Departamento de Química Física, Facultad de Ciencias, Universidad de Santiago de Compostela, Avda. Alfonso X El Sabio s/n, 27002 Lugo, Spain.
authors.forename: Victor Hugo
authors.initials: VH
authors.lastname: Soto Tellini
authors.forename: Aida
authors.initials: A
authors.lastname: Jover
authors.forename: Jorge Carrazana
authors.initials: JC
authors.lastname: García
authors.forename: Luciano
authors.initials: L
authors.lastname: Galantini
authors.forename: Francisco
authors.initials: F
authors.lastname: Meijide
authors.forename: José Vazquez
authors.initials: JV
authors.lastname: Tato