Supramolecular architecture of molecular crystals possessing shearing mechanical properties: columns versus layers

The supramolecular architectures of crystals of substituted benzenes possessing shearing mechanical properties have been analyzed from the viewpoint of energy of intermolecular interactions. It is demonstrated that suggested earlier layered structure of these crystals do not correspond to the character of intermolecular interactions. Analysis of the topology of intermolecular interactions indicates that the crystals have a columnar supramolecular architecture with weak interactions between the columns. The presence of shearing mechanical properties is caused by localization of intercolumnar interactions within some layers and a relatively small (less than 12 kcal mol(-1)) barrier of shift of molecules within this layer.