Halogen bonding and rotational disorder in chlorine clathrate hydrate cages.

We present a detailed theoretical characterization of the structure and interactions in dichlorine clathrate hydrate cages. In the case of the dodecahedral cage, there is clear evidence of the presence of halogen bonding, whereas in the tetrakaidecahedral cage, the expected signatures are there but in a weaker form. Comparison is made with the available structural data from x-ray experiments, where the rotational motion of dichlorine has been taken into account through Monte Carlo simulations illustrating delocalization effects associated with sampling multiple minima, specifically for the larger cage.

Halogen Bonds in Clathrate Cages: A Real Space Perspective.

In this paper we present real space analyses of the nature of the dihalogen-water cage interactions in the 5 and 5 6 clathrate cages containing chlorine and bromine, respectively. Our Quantum Theory of Atoms in Molecules and Interacting Quantum Atoms results provide strong indications that halogen bonding is present even though the lone pairs of water molecules are already engaged in hydrogen bonding interactions.

Communication: Evidence of halogen bonds in clathrate cages.

We present a theoretical characterization of the interaction of Cl and Br in the 5 and 56 clathrate cages, respectively, based on energy partitioning analysis and a study of the electronic shifts associated with transitions to the main valence bands. Our analysis clearly shows that while Br@56 does not show halogen bonding interactions in its equilibrium geometry, Cl@5 presents all the characteristics expected for halogen bonding. This is accomplished by the interaction of the usual sigma-hole with the lone pair of the closest oxygen atom involved in hydrogen bonding within the cage framework, though breaking of the hydrogen bond is not required.