Unexpected Strengthening of the H-Bond Complexes in a Polar Solvent Due to a More Efficient Solvation of the Complex Compared to Isolated Monomers

0563586 - ÚOCHB 2023 RIV US eng J - Článek v odborném periodiku
Miriyala, Vijay Madhav - Lo, Rabindranath - Bouř, Petr - Wu, Tao - Nachtigallová, Dana - Hobza, Pavel
Unexpected Strengthening of the H-Bond Complexes in a Polar Solvent Due to a More Efficient Solvation of the Complex Compared to Isolated Monomers.
Journal of Physical Chemistry A. Roč. 126, č. 43 (2022), s. 7938-7943. ISSN 1089-5639. E-ISSN 1520-5215
Grant CEP: GA ČR(CZ) GX19-27454X; GA ČR(CZ) GA20-10144S
Institucionální podpora: RVO:61388963
Klíčová slova: energy
Obor OECD: Physical chemistry
Impakt faktor: 2.9, rok: 2022
Způsob publikování: Omezený přístup
https://doi.org/10.1021/acs.jpca.2c05992

It is generally assumed that hydrogen-bonded complexes are less stable in solvents than in the gas phase and that their stability decreases with increasing solvent polarity. This assumption is based on the size of the area available to the solvent, which is always smaller in the complex compared to the subsystems, thereby reducing the solvation energy. This reduction prevails over the amplification of the electrostatic hydrogen bond by the polar solvent. In this work, we show, using experimental IR spectroscopy and DFT calculations, that there are hydrogen-bonded complexes whose stability becomes greater with increasing solvent polarity. The explanation for this surprising stabilization is based on the analysis of the charge redistribution in the complex leading to increase of its dipole moment and solvation energy. Constrained DFT calculations have shown a dominant role of charge transfer over polarization effects for dipole moment and solvation energy.
Trvalý link: https://hdl.handle.net/11104/0335497