We have designed phenylboronic acid group appended Ce(IV) bis(porphyrinate) double decker 1 and meso - meso linked porphyrin 2, useful for the allosteric binding of biologically important saccharides, Lewis oligosaccharides. Compound 1 binds Lewis oligosaccharides in aqueous media because of the boronic acid-diol interaction, but the complexation event can occur only above the critical concentrations because of the sigmoidal [oligosaccharide] versus [complex] isotherm. Compound 1 has a sufficiently high affinity with Lewis oligosaccharides (K = 105-106 M-2) with Hill coefficients n of 1.8-2.0, and LewisX series and Lewisa series give opposite, symmetrical CD spectra. This is the first example of efficient binding of Lewis oligosaccharides to the artificial receptor, which has become possible by positive homotropic allosterism.
ASJC Scopus subject areas
- Colloid and Surface Chemistry