Polyglycerol-Tagged Molecular Clips as Receptors in Protic Solvents



Four charge-neutral molecular clips modified with polyglycerol (PG) dendrons of first and second generation and with hyperbranched polyglycerols (HPG) in the central unit as solubilizing units were synthesized. Their use as supramolecular hosts for the complexation of several guest molecules such as caffeine, N-methylnicotinamide iodide, and Kosower salt was studied in methanol and water. Association constants and Gibbs enthalpies of association were determined by 1H NMR titration experiments. The obtained results were compared to the association behavior of molecular clips that carry anionic substituents. These results offer remarkable insights into the contribution of the substituents to host–guest binding and enable a strategy for improved substituent design.