Inspecting the role of synthons in the electronic transition of N-heterocyclic compounds

Intermolecular hydrogen bonding patterns allow us to draw a direct correlation between crystal structure and solid-state properties. To shed more light into the correlation between intermolecular patterns (e.g., synthons) and optical properties, here we prepared eight new crystal forms of template N-heterocyclic compounds. Their synthons were inspected in full detail, as well as the direct band gap of the electronic transitions were determined from their diffuse reflectance spectra and theoretically calculated using TDDFT. We could find a direct correlation between the synthons strength and the agreement between the theoretical and the experimental electronic transitions, evidencing an important role of the synthons in the electronic transition profile of N-heterocyclic compounds.(c) 2022 Published by Elsevier B.V.