A hydrogen-bonded CH2F2•••CO complex: ab initio and matrix isolation study

The structure and spectroscopy of hydrogen-bonded complexes of partially fluorinated methanes attract considerable interest from both fundamental and applied points of view. Here we report an experimental and theoretical study on CH2F2 center dot center dot center dot CO complex, which represents the first example of difluoromethane complex characterized by matrix isolation vibrational spectroscopy. According to the computations at the CCSD(T)/CBS (MP2/CBS) level of theory with ZPVE correction, the interaction energy of the most stable structure is 0.78 (0.84) kcal/mol. The calculated complexation-induced shifts for this structure are in reasonable agreement with experiment. The complex exhibits characteristic blue shifts of the C-H stretching modes (by 3.8 and 10.4 cm(-1) for symmetrical and antisymmetrical vibrations, respectively) and red shifts of the C-F stretching modes (by -0.8 and -4.2 cm(-1) for symmetrical and antisymmetrical vibrations, respectively); the C-O stretching is blue-shifted (+5.4 cm(-1)). The comparison of new complex with previously known species of this kind is discussed. (C) 2020 Elsevier B.V. All rights reserved.