Structure of cyclodextrins and their complexes

Influence of Single Skimmer Versus Dual Funnel Transfer on the Appearance of ESI-Generated LiCl Cluster/ß-Cyclodextrin Inclusion Complexes

Singly and doubly charged adducts of LiCl with β-cyclodextrin (βCD) of the type (βCD)(LiCl)(n)Li(+) and (βCD)2(LiCl)(p)Li2(2+) were studied using electrospray ionization mass spectrometry (ESI-MS). Insight into their structural composition was gained by analysis of their collision-induced dissociation (CID) mass spectra. The conditions the ions experience in the transfer region interfacing the ESI source and the mass analyzer were found to have a marked influence on the nature of the detected ions. In one instrument incorporating a single skimmer, individually attached LiCl ion pairs were observed, whereas the dual funnel ion guides of the second instrument allow the detection of previously unknown labile inclusion complexes of (LiCl)n clusters in βCD.

NMR spectra and dynamics of the sodium salt of per(6-thiobenzoic acid)-gamma-cyclodextrin

The solution-state NMR spectra of a per-6-substituted gamma-cyclodextrin show some interesting dynamic properties. At high temperature (353 K), the (1)H NMR spectrum shows dynamic averaging of the different conformations. This averaging is no longer observed on cooling of the cyclodextrin solution to 278 K, resulting in NMR spectra with a large (1)H and (13)C chemical shift dispersion. The complete assignment of the eight unique glucosyl residues was achieved using COSY, HSQC and exchange spectroscopy. A ROESY spectrum, with a short mixing time to reduce the effects of exchange, gives correlations that lead to the determination of the connectivity of all eight glucosyl residues. On the NMR time-scale, the cyclodextrin is highly dynamic; the lower temperature minimum energy conformation has one of the aromatic rings self-complexed and a distorted cyclodextrin torus.

Molecular Mechanics Study of the Inclusion Complexes of 2-Methyl Naphthoate with alpha- and beta-Cyclodextrins

Molecular mechanics calculations were employed to study the inclusion of 2-methyl naphthoate in alpha- and beta-cyclodextrin in vacuo and in the presence of water as a solvent. The driving forces for complexation are dominated by nonbonded van der Waals host:guest interactions in both environments. The 2-methyl naphthoate penetrates completely into the cavity of beta-cyclodextrin, but there is only partial penetration by the same molecule into the smaller cavity of alpha-cyclodextrin. Copyright 1997Academic Press