Metal complexes of functionalized cyclodextrins as enzyme models and chiral receptors

Cyclodextrins (CDs) are cyclic oligomers of alpha-1,4 linked D-glucopyranos e. The main feature of CDs is an hydrophobic cavity which renders these mol ecules unusual. By appropriate functionalization new systems can be obtaine d and the features of these molecules can be increased and modulated. Among the various applications the building of molecular receptors and enzyme mo dels by cyclodextrins is a particularly fascinating field. The present revi ew will be a survey of the metal complexing properties of CDs and a report on some recent results of metal complexes formed by functionalized cyclodex trins. The metal ion can assist the host-guest interaction often increasing the properties of CDs to act as chiral receptors. Furthermore it can act a s catalytic center in the mimicking of some metallo-enzyme models by functi onalized cyclodextrins. (C) 1999 Elsevier Science S.A. All rights reserved.