Fluorescent Molecular Cages with Sucrose and Cyclotriveratrylene Units for the Selective Recognition of Choline and Acetylcholine.

The synthesis of four fluorescent diastereoisomeric molecular cages containing cyclotriveratrylene and sucrose moieties connected via the naphthalene linkers is reported. These diastereoisomers were found to be selective and efficient receptors for acetylcholine and choline. Compound P-5a has a better affinity for choline over acetylcholine, while cage M-5a exhibits a higher association constant for acetylcholine over choline. The highest selectivity value was observed for compound M-5a (KACh/KCh = 3.1). Cages P-5a, P-5b, M-5a, and M-5b were fully characterized by the advanced NMR techniques, and ECD spectroscopy was supported by DFT calculations. The binding constants Ka of these receptors were determined by fluorescence titration experiments in acetonitrile.