Recognition site modifiable tetrapodal receptor and the effect of alkane chains on monosaccharide recognition

Abstract

Traditional molecular recognition studies usually focus on obtaining strong host–guest interactions, which may lead to the neglect of important tendencies caused by other factors. Moreover, most receptors typically fix their recognition sites in the backbone of the receptor, resulting in great synthetic challenges for varying recognition functional groups. In this contribution, we developed a new class of tetrapodal receptors. The terminal functional groups of the receptor can be varied by simple chemistry. Through ¹H NMR titration experiments and binding constant analysis, the influence of the size and shape of alkane chains on monosaccharide recognition was investigated. The introduction of ester functional groups allows the access of moderate binding affinity to unveil otherwise masked contribution of dispersion force in saccharide recognition. These results also imply that stronger forces may not always be beneficial for host–guest binding while functional groups with a particular shape may favor the discrimination of isomers through steric hindrance effect. Thereby, these tetrapodal receptors and their analogues provide an ideal platform for comparing the effects of various functional groups on molecular recognition.