The Design of Molecular Artificial Sugar Sensing Systems

Abstract

A review with 24 refs. This article is concerned with the development of new receptor mols. that can precisely recognize sugar mols. by making use of the reversible formation of boronate esters from suitable diols and boronic acids. Since one boronic acid can react with cis-1,2-diols or cis-1,3-diols to form a boronate ester, one diboronic acid can immobilize two suitably positioned diol units to form a sugar-contg. macrocycle that can discriminate between the relative positions of cis-diol moieties on the guest saccharide. When a boronic acid-based receptor contains an aminomethylfluorophore, the complexation event can be conveniently read out by fluorescence spectroscopy. This is a novel application of PET (photoinduced electron transfer) sensors: sugar binding changes the strength of the B...N interaction which consequently changes the fluorescence quenching efficiency of the amine. The authors demonstrated, using a chiral 1,1'-binaphthyl group as a fluorophore, that even discrimination between enantiomeric saccharides is possible. These abundant examples support the superiority of boronic acid-based covalent-bond recognition over hydrogen bond-based noncovalent-bond recognition for sugars in water. [on SciFinder (R)]