Ab Initio Molecular Dynamics Study of the Very Short O–H···O Hydrogen Bonds in the Condensed Phases

Abstract

In this paper are presented the results of theoretical studies of the structure and proton motion in very short O···O intramolecular hydrogen bonds in two molecular crystals. A comparison was conducted between 3-cyano-2,4-pentanedione (I) and 4-cyano-2,2,6,6-tetramethyl-3,5-heptanedione (II) in the solid state. The dynamics of proton motion in the O-H···O hydrogen bond were investigated in he NVT ensemble at 298 and 50 K, respectively, for crystals I and II using Car-Parrinello and path integral molecular dynamics. Very large delocalization of the bridging proton was noted especially in the path integral simulation where quantum effects are taken into account. The infrared spectrum was calculated, and a comparative vibrational analysis was performed. CPMD vibrational results appear to be in qualitative agreement with the experimental ones.

Symmetry and dynamics of FHF− anion in vacuum, in CD2Cl2 and in CCl4. Ab initio MD study of fluctuating solvent–solute hydrogen and halogen bonds

“…The labelling of fluorine atoms (a and b) was done arbitrarily and kept consistent during the analysis deviation for FÁ Á ÁD distance in PIMD is 0.097 Å and in our Born-Oppenheimer MD simulation it equals to 0.063 Å. In general, nuclear quantum effects are without a question important for a neat description of strong H-bond parameter distribution, [21][22][23][24] however in this paper we focus on solvent-solute interactions and comparisons of different types of specific interactions in condensed phase. Note, that the distribution of spectroscopic parameters is rather broad even without the influence of fluctuating solvent molecules in the solvation shell.…”

“…The nuclear quantum effects on distribution of bridging proton position could be accounted for by using path integral molecular dynamics simulations (PIMD). Recently, this approach has been applied to short OHO, 21 OHN 22 and other hydrogen bonds, including intramolecular ones 23 and the ones found inside the active sites of enzymes. 24 One of the most famous examples of an extremely strong and short symmetric hydrogen bond is FHF À anion.…”

Car–Parrinello and path integral molecular dynamics study of the intramolecular hydrogen bonds in the crystals of benzoylacetone and dideuterobenzoylacetone

“…This appears to confirm the need to use dispersion corrections to the full energy for calculations on the DFT method level. 47…”

Intramolecular proton transfer reaction dynamics using machine learned ab initio potential energy surfaces

“…MA and its derivatives come from the 1,4-diketones family, where some of the a) Electronic mail: shampa.santra@gmail.com shortest intramolecular hydrogen bond distances are realized. [30][31][32][33][34][35][36][37][38][39] The low energy barrier proton transfer (PT) in such enolized systems is known to occur due to the π-delocalization over the six-membered cyclic transition state (TS) structure. 36,37 The introduction of electron-donating and/or electronwithdrawing functional groups modulates the barrier height.…”