The mechanics of hydrogen bond formation in conjugated systems

Abstract

The theory of atoms in molecules provides an atomic view of the mechanics governing the interactions between molecules and as such it facilitates both an understanding of the interactions and the manner in which they can be modified. This theory is applied to a study of the changes in the energies, electron populations, volumes and moments of the atoms of formamide upon dimerization to form both the cyclic and open hydrogen-bonded structures. An important factor governing the changes in the relative stabilities of the atoms on forming the dimers are the opposing flows of σ and π density through conjugated NCO fragments, as measured by the shift in the electron populations into or out of the plane of the nuclei over each of the atomic basins and by the changes in the ellipticities of the atomic distributions.