Analysis and prediction of intermolecular interactions
Atom-atom potentials not only represent a classical approach in organic solid state chemistry: They may be used successfully in the chemical crystallography of inorganic molecular compounds. After a brief review of its basic concepts the method is applied to the study of solid state properties of organometallic and coordination compounds. Lattice energy minimizations based on an empirical parameter set and a Buckingham pair potential allow to model essential features of the energy hypersurface subtended by the packing variables, namely location and relative height of the energy minima and curvature of the surface. For compounds of moderate polarity the experimentally established structures correspond to geometries associated with favorable energies. Besides reproducing (or, in simple cases, predicting) the molecular arrangement in van der Waals crystals the method allows to discuss the relative heights of the extrema: In agreement with the expectations very similar lattice energies are obtained for different polymorphs. Finally it is demonstrated how the atom-atom approximation may be used to probe the curvature of the energy hypersurface. The concept is found apt to describe situations of static disorder and dynamic large-amplitude motions and to analyze discrepancies from van der Waals behavior.
Lattice energy methods for
inorganic molecular solids. In Advances in Molecular Structure Research
U. Englert; M. Hargittai and I. Hargittai Eds., JAI Press
Inc.:Greenwich, Connecticut, 2000, 6,
49-74
Prediction of Crystal Structures
M. U. Schmidt and U. Englert; J. Chem. Soc. Dalton Trans. 1996, 2077-2082
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Ulli(1996-10-01, 2005-01-08)