Molecular design and synthetic strategy for multifunctional artificial receptors: recent examples

Artificial ribofuranoside receptors represent the molecular design and the synthetic strategy for our multifunctional artificial receptors. The design of the polypyridine-macrocyclic ribofuranoside receptors was based on the multipoint hydrogen bond complementarity between the receptors and methyl β- (D) -ribofuranoside. The binding affinity of the receptors for the ribofuranoside in CDCl₃ was very high (up to K_a = 5.2 × 10³ M^-1), so that even native ribose was extracted by them into such nonpolar solvents. Selective extraction of ribose by the receptors was observed. The selectivity is governed by the OH direction and the whole size of the sugars as well as their shapes. Furthermore, fluorescence emission of the receptors was largely enhanced in the presence of methyl β-(D)-ribofuranoside or ribose.