Blue-shift of the C-H stretching vibration in CHF3-H2O complex: Matrix isolation infrared spectroscopy and ab initio computations

As a result of hydrogen bonding in CHF3-H2O complex, ab initio computations exhibited a blue shift in the C-H stretching region of CHF3 sub-molecule. In this work, we have investigated whether the blue-shifting in CHF3-H2O complex can be experimentally discerned using matrix isolation infrared spectroscopy. The 1:1 CHF3-H2O complex was therefore trapped and studied in argon and neon matrices. Experimentally a blue shift of 20.3 and 32.3 cm−1 in the C-H stretching region of CHF3 sub-molecule for the CHF3-H2O complex was observed in argon and neon matrices. The structure of the complex and the energies were computed at MP2 level of theory using a 6-311++G(d,p) and aug-cc-pVDZ basis sets. Computations indicated only one minimum corresponded to a C-H⋯O interaction between the hydrogen of fluoroform and oxygen of water. AIM and NBO analyses were performed to understand the reasons for blue-shifting of the C-H stretching wavenumber in the complex.