Predicting guest orientations in layered double hydroxide intercalates

Molecular mechanics have been used to rationalize the structures of the layered double hydroxide intercalates [LiAl2(OH)(6)]Cl, [LiAl2(OH)(6)]Br, and [LiAl2(OH)(6)]NO3. The simulations showed that calculated lowest energy structures were in good agreement with the experimentally determined structures and were able to explain the positional disorder of the NO3- guest anions found in the structure of [LiAl2(OH)(6)]NO3. Furthermore, the calculations also proved to be a useful predictive tool for the interlayer spacing and consequently the guest orientation in the related intercalates [LiAl2(OH)(6)](2)CO3, [LiAl2(OH)(6)](2)-SO4, and [LiCAl2(OH)(6)](2)C2O4, for which the structures have not been determined by conventional diffraction techniques.