Solvent- and temperature-tuned orientation of ferrocenyl azide inside beta-cyclodextrin.
An induced circular dichroism (ICD) solution study on the orientation of ferrocenyl azide within the beta-cyclodextrin cavity is described. In DMSO, ferrocenyl azide prefers an axial inclusion, whereas in ethylene glycol and DMSO/H2O = 50/50 an equatorial alignment dominates. As shown by temperature-dependent ICD spectra, at lower temperatures ferrocenyl azide adopts preferentially an equatorial arrangement, whereas at higher temperatures an axial one is favored. Temperature and solvent effects on the co-conformation of ferrocene noncovalently bound to cyclodextrin have never been observed before.
Walla
Peter
P
Institut für Organische Chemie, Universität Wien, Währinger Strasse 38, A-1090 Wien, Austria.
Arion
Vladimir B
VB
Brinker
Udo H
UH