Carbohydrate-based receptors with multiple thiourea binding sites. Multipoint hydrogen bond recognition of dicarboxylates and monosaccharides

The binding properties of multitopic sugar thiourea receptors toward dicarb oxylate and monosaccharide guests have been examined taking glutarate and o ctyl P-D-glucopyranoside as model ligands. For the anionic hydrogen bond ac ceptor, both the complex stoichiometry and the association constants (K-as) were found to be strongly dependent on the relative disposition of recogni tion elements in the host. In contrast, for the glucoside guest a 1:1 stoic hiometry was observed in all cases, the K-as values being largely independe nt of the unbound state provided that geometrically equivalent supramolecul ar topologies can be achieved.