An Octa-Urea [Pd2 L4 ]4+ Cage that Selectively Binds to n-octyl-α-D-Mannoside.

Abstract

Designing compounds for the selective molecular recognition of carbohydrates is a challenging task for supramolecular chemists. Macrocyclic compounds that incorporate isophtalamide or bisurea spacers linking two aromatic moieties have proven effective for the selective recognition of all‐equatorial carbohydrates. Here, we explore the molecular recognition properties of an octa‐urea [Pd2L4]4+ cage complex (4). It was found that small anions like NO3 − and BF4 − bind inside 4 and inhibit binding of n‐octyl glycosides. When the large non‐coordinating anion ‘BArF’ was used, 4 showed excellent selectivity towards n‐octyl‐α‐D‐Mannoside with binding in the order of K a≈16 M−1 versus non‐measurable affinities for other glycosides including n‐octyl‐β‐D‐Glucoside (in CH3CN/H2O 91 : 9).