Are C-H groups significant hydrogen bonding sites in anion receptors? Benzene complexes with Cl-, NO3-, and ClO4-.
Theoretical calculations,examination of crystallographic data, and experimental binding energies suggest that even in the absence of electron-withdrawing substituents, simple arenes such as benzene form hydrogen bonds with anions that can exceed 50% of the strength of those formed by O-H and N-H groups. Thus, when present in a receptor, even moderately acidic C-H groups can significantly enhance the anion binding affinity and they should be considered as additional binding sites within the host cavity.
Bryantsev
Vyacheslav S
VS
Chemical Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99352, USA.
Hay
Benjamin P
BP