Structure and dynamics of dodecaborate clusters in water.

We have studied using molecular dynamics simulations the interaction of the dodecaborate anion, B(12)H(12)(2-), and its amino, trimethyl, and triethyl derivatives with water molecules. We found peculiar organization of the water molecules in the first solvation shell with the formation of a dihydrogen bond between the hydrogen atoms of the anions and the hydrogen atoms of the water molecules. The simulations also show that the organization of the hydration shell is strongly influenced by the substituents in the anions. These differences are likely to play an important role in understanding the interaction of the anions with biological systems like membranes and proteins in aqueous environments.