Stretching force constants as descriptors of energy and geometry of F•••HF hydrogen bonds

In this work applicability of proton donor group stretching vibration force constants k(s) and intermolecular stretching force constants k(sigma) for evaluations of hydrogen bond strength and geometry are discussed. For a set of 30 complexes with F center dot center dot center dot HF hydrogen bonds in a wide range 05-48 kcal/mol by means of quantum chemical calculations equilibrium geometries, complexation energies, vibrational frequencies and corresponding force constants were calculated (MP2/aug-cc-pVE). It is shown, that properties of a hydrogen bond are more strictly correlated with the values of force constants than with vibrational frequencies. Easy-to-use equations for estimations of hydrogen bond energy Delta E and geometry (r(FH), r(FF)) based on k(s) and k(sigma) values are proposed. (C) 2020 Elsevier B.V. All rights reserved.