Hydrogen bonding patterns and dynamics in the hydration of biological macromolecules.

In crystalline cyclodextrin hydrates O–H . . . Ο hydrogen bonds occur in homodromic chainlike and cyclic motifs. In β-cyclodextrin· 11 H2O, where OH-groups are disordered, flip-flop hydrogen bonds O–(1/2H) . . . (1/2H)–O are found which represent a dynamical equilibrium O–H . . . . . . H–O. Detailed insight into otherwise hidden structural aspects of hydration and water structure (clusters) become available.