HYDROGEN-BONDED (CX$_3$)$_2$O$\cdots$HF (X=H, D) COMPLEXES: INFRARED SPECTRA AND MODELING WITHIN THE DENSITY FUNCTIONAL THEORY AND TOPOLOGICAL ANALYSIS METHODS

We study hydrogen-bonded (CX3)2O···HF (with X= H, D) complexes that play an important role in intermolecular interactions in the gas and liquid phases. We investigate the vibrational and rotational characteristics of these complexes using infrared spectroscopy, density functional theory (DFT) calculations, and topological analysis methods, including atoms in molecules (AIM), noncovalent interactions (NCI), and reduced density gradient (RDG). Infrared spectroscopic measurements were conducted at 188 K with a Bruker IFS-120 HR vacuum Fourier transform spectrometer. The data obtained revealed significant red shifts in the HF stretching frequencies due to hydrogen bonding. The DFT calculations at the B3LYP/6-311++G(d,p) level confirm the structural rearrangement and frequency shifts upon complex formation. The calculated vibrational frequencies agree well with the experimental data. This agreement confirms the reliability of the chosen theoretical approach. The AIM, NCI, and RDG analyses provide a detailed characterization of the hydrogen bond in (CX3)2O···HF. The bond critical point analysis indicates a strong electrostatic interaction, while NCI and RDG results confirm the contribution of dispersion forces to the overall stability of the complex. This study enhances our understanding of hydrogen-bonded complexes, offering insights into their spectroscopic properties and structural dynamics. The findings contribute to a deeper comprehension of hydrogen bonding mechanisms in various molecular environments.