Crystallography Aided by Atomic Core‐Level Binding Energies: Proton Transfer versus Hydrogen Bonding in Organic Crystal Structures

Abstract

Ionic bond or hydrogen bridge? Brønsted proton transfer to nitrogen acceptors in organic crystals causes strong N1s core-level binding energy shifts. A study of 15 organic cocrystal and salt systems shows that standard X-ray photoelectron spectroscopy (XPS) can be used as a complementary method to X-ray crystallography for distinguishing proton transfer from H-bonding in organic condensed matter.