Investigation of [CHCl3-CH3OH] complex using matrix-isolation IR spectroscopy and quantum chemical calculation: Evidence of hydrogen- and halogen-bonding interaction

Abstract

• First molecular level investigation of [CHCl 3 -CH 3 OH] complex using Matrix isolation FTIR. • Dimers are characterised by C-H—O, O-H—Cl hydrogen bond and C-Cl—O halogen bond. • First experimental evidence of formation of halogen bond in CHCl 3 . • C-H—O hydrogen bonded complex is also identified in the low temperature matrix. • Structure, relative stability, and nature of interactions are calculated. Mixture of CHCl 3 -CH 3 OH is a popular non-aqueous solvent mixture that exhibits strong synergistic solvation. The specific interaction between the CHCl 3 and CH 3 OH is investigated using 1:1 complex in N 2 matrix along with electronic structure calculation. Three different type of interactions are possible between CHCl 3 and CH 3 OH at the molecular level: C-H · · · O hydrogen bond, O-H · · · Cl hydrogen bond, and C-Cl · · · O halogen bond. One C-H · · · O hydrogen bond minimum, two O-H · · · Cl hydrogen bond minima, and one C-Cl · · · O halogen bond minimum are obtained on the [CHCl 3 -CH 3 OH] dimer potential energy surface. Formation of C-H · · · O hydrogen bonded and C-Cl · · · O halogen bonded 1:1 complex of [CHCl 3 -CH 3 OH] in N 2 matrix is confirmed using experimental and simulated IR spectra. The outcome of the current work would help to explain the specific interactions present in CHCl 3 and CH 3 OH binary solvent mixture and to estimate the responses of such non-aqueous solvent mixture.