Glycosylated tris-bipyridine ferrous complexes to provide dynamic combinatorial libraries for probing carbohydrate-carbohydrate interactions

2,2-Bipyridines having beta-lactoside, beta-D-glucoside, beta-D-galactoside, and N-acetyl-beta-D-glucosaminide were prepared and then, complexed with ferrous ion to afford trivalent glycoclusters having tris-bipyridine ferrous complex cores. Each glycocluster provides a dynamic combinatorial library composed of four diastereomeric stereoisomers (Delta mer, Delta fac, Delta mer, and Delta fac) whose ratios depend on their relative stabilities. CD spectral analyses of these glycoclusters showed that various cations (Na+, Mg2+, K+ or Ca2+) enriched Delta-forms of the glycocluster having beta-lactosides and N-acetyl-beta-D-glucosaminides possibly by cations-induced intramolecular carbohydrate-carbohydrate interactions. (C) 2013 Elsevier Ltd. All rights reserved.