Estimations of OH·N hydrogen bond length from positions and intensities of IR bands

• Published in: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy Molecular and biomolecular spectroscopy, 2022-07, Vol.275, p.121172, Article 121172
• Main Authors: Tupikina, E.Yu, Titova, A.A., Kaplanskiy, M.V., Chakalov, E.R., Kostin, M.A., Tolstoy, P.M.
• Format: Article
• Language: English
• ISSN: 1386-1425
• DOI: 10.1016/j.saa.2022.121172

[Display omitted] •Hydrogen bonds OHN.•“Recipes” of spectral IR diagnostic of hydrogen bond geometry.•Equations linking hydrogen bond length O…N and IR parameters. In this computational work applicability of IR spectral parameters for evaluations of OH···N hydrogen bond length is discussed. For a set of 124 complexes with OH···N hydrogen bond formed by combinations of methanol/acetic acid and pyridine (and their fluorine substituted versions) geometries, energies and IR parameters were calculated at MP2/def2-TZVP level of theory. For a number of IR parameters (the shift of proton donor group stretching vibration Δνs, increase of its intensity I, the low-frequency hydrogen bond stretching vibration νσ, bending in-plane δ and out-of-plane γ vibrations) equations linking them with interatomic distances are proposed, the robustness and accuracy of such equations are discussed. The enthalpy of OH···N hydrogen bond formation ΔH was also linked with electron density parameters in (3; –1) critical point.