The electronic structure of the C2H4O•••2HF tri-molecular heterocyclic hydrogen-bonded complex:: a theoretical study

The geometries of three isomers of the C2H4O center dot center dot center dot 2HF tri-molecular heterocyclic hydrogen-bonded complex were examined through B3LYP/aug-cc-pVDZ calculations. Analysis of structural parameters, determination of CHELPG (charge electrostatic potential grid) intermolecular charge transfer, interpretation of infrared stretching modes, and Bader's atoms in molecules (AIM) theory calculations was carried out in order to characterize the hydrogen bonds in each isomer of the C2H4O center dot center dot center dot 2HF complex. The most stable structure was determined through the identification of hydrogen bonds between C2H4O and HF, (O center dot center dot center dot H), as well as in the hydrofluoric acid dimer, (HFD-R center dot center dot center dot HFD). However, the existence of a tertiary interaction (F-lambda center dot center dot center dot H-alpha) between the fluoride of the second hydrofluoric acid and the axial hydrogen atoms of C2H4O was decisive in the identification of the preferred configuration of the C2H4O center dot center dot center dot 2HF system.