Investigation of the molecular level interaction in [CH3OH-CH2X2] complexes (X = I, Br, and Cl) using matrix-isolation IR spectroscopy

The [CH3OH-CH2X2] (X = Cl, Br, and I) complexes have been studied to understand the tendency towards the formation of hydrogen bonds and halogen bonds. Three different types of interactions viz., C-X· · ·O, C-H· · ·O, and O-H· · ·X, are possible between the CH3OH and CH2X2. Experiments have been carried out in low-temperature N2 matrix using Fourier Transform Infrared spectroscopy. Electronic structure calculations have been performed to identify the possible binding motifs between CH2X2 and CH3OH. Formation of more than one complex has been confirmed in [CH3OH CH2X2] (X = Br and I) mixture, using the experimental and simulated IR spectra, whereas only one type of complex is found in [CH3OH CH2Cl2] mixture. Energy decomposition analysis, quantum theory of atoms in molecules, and non-covalent interaction analysis have been performed to understand the nature of interaction and the driving force for complexation under experimental conditions.