title: Macrocycle conformation and self-inclusion phenomena in octakis(3-O-butanoyl-2,6-di-O-pentyl)-gamma-cyclodextrin (Lipodex E) by NMR spectroscopy and molecular dynamics.
abstract: Octakis(3-O-butanoyl-2,6-di-O-pentyl)-gamma-cyclodextrin (Lipodex E) is a lipophilic chiral selector successfully used for the enantioselective gas chromatographic separation of a multitude of racemic analytes. NMR data (13C chemical shifts, 3J(HH), rotating frame NOEs (ROEs)) and molecular dynamics (MD) simulations point out that the macrocycle is distorted with respect to the canonical truncated-cone shape of native cyclodextrins, although C(8) symmetry is retained on the NMR timescale. ROE data and MD trajectories provide evidence for self-inclusion of one 6-O-pentyl pendant chain within the cavity of Lipodex E. The interpretation of long-range and low-intensity ROEs is supported by the calculation of average internuclear distances by using the radial distribution function (RDF) calculated from MD trajectories. MD simulations are eventually used to compare the flexibility of the macrocycle of Lipodex E with that of native gammaCD.
authors.affiliation: Dipartimento di Chimica, Materiali ed Ingegneria Chimica 'G. Natta'-Politecnico di Milano, Via L. Mancinelli 7, I-20131, Milano, Italy. andrea.mele@polimi.it
authors.forename: Andrea
authors.initials: A
authors.lastname: Mele
authors.forename: Giuseppina
authors.initials: G
authors.lastname: Raffaini
authors.forename: Fabio
authors.initials: F
authors.lastname: Ganazzoli
authors.forename: Markus
authors.initials: M
authors.lastname: Juza
authors.forename: Volker
authors.initials: V
authors.lastname: Schurig
mesh_terms: D003198:Computer Simulation; D003505:Cyclodextrins / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008968:Molecular Conformation; D015394:Molecular Structure; D013997:Time Factors; D047408:gamma-Cyclodextrins
chemical_list: D003505:Cyclodextrins; D047408:gamma-Cyclodextrins; C113626:octakis(3-O-butanoyl-2,6-di-O-pentyl)cyclodextrin