Microscopic and Bulk Elastic Properties in Supramolecular Systems: Guest–Host Interactions in Dianinʹs Inclusion Compounds

The relationship of bulk properties of materials to the microscopic interactions of the moieties that comprise them is demonstrated by connecting the guest–host interactions of a series of crystals of Dianinʹs inclusion compounds to their bulk moduli of elasticity and linear compressibilities. These quantities’ values are presented for the guest-free Dianinʹs lattice, the clathrand, as well as Dianinʹs inclusion compounds with ethanol and heptanol guests. The role of collective vibrational states of the crystals is emphasized in determining the bulk elastic properties of these supramolecular materials. Microscopic guest–host interactions are examined to rationalize the trends in the observed macroscopic elastic properties. The use of elastic multipoles and mechanical susceptibilities is suggested as a way of modeling the interactions of molecules in solids so that the collective and local interactions can be included in designing the desired bulk properties of materials. The use of elastic multipoles in a fashion similar to atomic orbitals in understanding intermolecular interactions in a solid is discussed.