Evaluation of the Lattice Energy of the Two-Component Molecular Crystals Using Solid-State Density Functional Theory

The lattice energy E latt of the two-component crystals (three co-crystals, a salt, and a hydrate) is evaluated using two schemes. The first one is based on the total energy of the crystal and its components computed using the solid-state density functional theory method with the plane-wave basis set. The second approach explores intermolecular energies estimated using the bond critical point parameters obtained from the Bader analysis of crystalline electron density or the pairwise potentials. The E latt values of two-component crystals are found to be lower or equal to the sum of the absolute sublimation enthalpies of the pure components. The computed energies of the supramolecular synthons vary from ∼80 to ∼30 kJ/mol and decrease in the following order: acid–amide > acid–pyridine > hydroxyl–acid > amide–amide > hydroxyl–pyridine. The contributions from different types of noncovalent interactions to the E latt value are analyzed. We found that at least 50% of the lattice energy comes from the heterosynthon and a few relatively strong H-bonds between the heterodimer and the adjacent molecules.