Stereoselective self-assembly of atropoisomeric Pd(II) metallocycles induced by an aromatic guest

摘要

A new dinuclear Pd(II) metallocycle consisting of a 4,4'-bipyr-idin-1-ium ligand with a quinoline moiety was self-assembled in aqueous solution with the aid of template molecules; the situation found in solution in which both syn and anti or only the anti atropoisomers are observed strongly relies on the intermolecular host-guest interactions.rnThe facile obtention of macrocycles with cavities large enough to accommodate substrate molecules in complexation processes is of enormous importance in host-guest chemistry. The structural characteristics of their cavities, including shape, size and flexibility, determinate the usefulness of the receptors towards target substrates. Metal-directed self-assembly has emerged as a powerful tool to obtain molecular hosts of defined shapes and sizes. The design of receptors capable of adapting their structure to bind the guest in a manner reminiscent of Koshland's induced model for substrate binding to enzymes has attracted much attention because such induced fit is the basis of many allosteric systems.