Role of the Symmetry of Multipoint Hydrogen Bonding on Chelate Cooperativity in Supramolecular Macrocyclization Processes.

Herein, we analyze the intrinsic chelate effect that multipoint H-bonding patterns exert on the overall energy of dinucleoside cyclic systems. Our results indicate that the chelate effect is regulated by the symmetry of the H-bonding pattern, and that the effective molarity is reduced by about three orders of magnitude when going from the unsymmetric ADD-DAA or DDA-AAD patterns to the symmetric DAD-ADA pattern.