1,1′-Binaphthyl substituted calixresorcinols–methyl red complexes: receptors for optical saccharide sensing

Novel 1,1′-binaphthyl substituted calixresorcinols (1 and 2) were synthesized. Macrocycles 1 and 2 form water-soluble complexes with methyl red 3, which are, in turn, able to bind saccharides by a competition process in aqueous media and which exhibit color transitions during titration. Preferential binding of oligosaccharides compared to monosaccharides was found. The association constants of effectively bound oligosaccharides in aqueous media varied around 103 M−1.