title: Influence of the macroring size on the self-association thermodynamics of cyclodextrins with a double-linked naphthalene at the secondary face.
abstract: The conformational properties and aggregation behavior of two selectively modified cyclomaltooligosaccharides (cyclodextrins, CDs) containing a double-linked 1,8-dimethylnaphthalene cap-like moiety at the secondary face, namely, 2(I),3(I)-O-(1,8-dimetylnaphthalene-α,α'-diyl)-per-O-Me-α- and -γ-cyclodextrins (NmαCD and NmγCD, respectively), in water and in organic solvents were investigated. Both CD derivatives self-associated in water to form dimer species, but the characteristics of the dimerization process and of the resulting dimer strongly depended on the size of the macrocycle. Dimerization constants, thermodynamic parameters upon association, and information about the preferred conformations of the monomer and dimer CD structures were obtained by using NMR, UV-vis, steady-state and time-resolved fluorescence, and circular dichroism experimental techniques, as well as molecular mechanics (MM) and molecular dynamics (MD) simulations. The complexation of 1,8-di(methoxymethyl)naphathalene (oNy) and the heteroassociation of both NmCDs with their permethylated CD partners (mCDs), lacking the aromatic cap, were examined. In addition, the influence of the size of the chromophore moiety on the thermodynamics of self-association was also assessed by comparison of the results obtained for the new naphthalene derivatives with those of the 2(I),3(I)-O-(1,2-xylylene)-modified CD analogues (XmCDs).
authors.affiliation: Departamento de Química Física, Universidad de Alcalá, Madrid, Spain.
authors.forename: M José
authors.initials: MJ
authors.lastname: González-Álvarez
authors.forename: Juan M
authors.initials: JM
authors.lastname: Benito
authors.forename: José M
authors.initials: JM
authors.lastname: García Fernández
authors.forename: C
authors.initials: C
authors.lastname: Ortiz Mellet
authors.forename: Francisco
authors.initials: F
authors.lastname: Mendicuti
mesh_terms: D003505:Cyclodextrins / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation; D056004:Molecular Dynamics Simulation; D009281:Naphthalenes / Q000737:chemistry*; D010316:Particle Size; D013499:Surface Properties; D013816:Thermodynamics
chemical_list: D003505:Cyclodextrins; D009281:Naphthalenes