Ab initio and DFT studies of hydrogen bond interactions in difluoroacetic acid dimer

Abstract

Density functional theory (DFT) and ab initio calculations were performed for difluoroacetic acid (DFA). Eight theoretically possible conformers were considered and by using conformational analysis only three stable conformers were found. The hydrogen bonding interaction of DFA complex has been investigated using DFT and ab initio methods for cis conformers. Stabilization energies of dimers including basis set superposition error and ZPE were found in the range 8.89-13.08 kcal mol -1 . It was found that EFC dimer is slightly more stable. Red shift of O-H bond in the range -226.3 to 505.7 cm -1 predicted for dimers. The natural bond orbital analysis was applied to characterize nature of the interaction.

Thermal and Solvent Effects On NMR Indirect Spin–Spin Coupling Constants of a Prototypical Chagas Disease Drug

“…Classically, hydrogen bonds are thought to arise from the electrostatic interaction of a positively charged H atom and an electronegative atom X (usually F, O, and N) . However, electronic delocalization between solute and solvent molecules may also occur and lead to a partially covalent character for such bonds. − It is generally assumed that the classical contributions to hydrogen bonding can be treated by continuum solvation models as long as the interaction between solute and solvent is moderately polar. , Such models − are widely used today and have often been applied with success . On the other hand, it is also clear that the electronic effects of specific interactions between solute and solvent are better evaluated by inclusion of explicit solvent molecules. ,, This applies in particular to solvent molecules in the first coordination shell with strong and specific solute–solvent interactions that cannot be considered in a continuum model …”

Determination of the Novel Insecticide Flupyradifurone and Its Two Metabolites in Traditional Chinese Herbal Medicines Using Modified QuEChERS and High-Performance Liquid Chromatography-Tandem Mass Spectrometry

“…DFA was adsorbed on all the sorbents except for C 18 and GCB, with its adsorption on PSA being strongest. Chermahini et al [ 23 ] found that DFA has only three stable conformations; cis DFA has two stable conformers, EHC and EFC, while trans DFA has one stable conformer, EHT. The stability of the DFA monomers follows the order EHC > EFC > EHT.…”

Interplay of thermochemistry and Structural Chemistry, the journal (volume 21, 2010) and the discipline

“…In the theoretical study by Chermahini et al [170] DFT and ab initio calculation were employed to study the hydrogen bond interactions of dimer of difluoroacetic acid. Eight different conformers were considered.…”