Glucose Binding Drives Reconfiguration Of A Dynamic Library Of Urea-Containing Metal-Organic Assemblies

A bis-urea-functionalized ditopic subcomponent assembled with 2-formylpyridine and Fe-II, resulting in a dynamic library of metal-organic assemblies: an irregular (Fe4L6)-L-II structure and three (Fe2L3)-L-II stereoisomers: left- and right-handed helicates and a meso-structure. This library reconfigured in response to the addition of monosaccharide derivatives, which served as guests for specific library members, and the rate of saccharide mutarotation was also enhanced by the library. The (P) enantiomer of the (Fe2L3)-L-II helical structure bound beta-D-glucose selectively over alpha-D-glucose. As a consequence, the library collapsed into the (P)-(Fe2L3)-L-II helicate following glucose addition. The alpha-D-glucose was likewise transformed into the beta-D-anomer during equilibration and binding. Thus, beta-D-glucose and (P)-3 amplified each other in the product mixture, as metal-organic and saccharide libraries geared together into a single equilibrating system.