Investigation of [CH2I2–R2S] complexes (R = –H, –CH3) in cryomatrix: Propensity towards C–I⋯S halogen bond and C–H⋯S hydrogen bond interaction

Abstract

The volatile organic iodine compound (Image 1) and volatile bivalent sulphur compounds, such as, Image 2, Image 3, are trace gases present with high concentration in the coastal area and are important constituents for the chemical processes in the area of atmospheric science. The Image 4 is one of the iodine precursors in the atmosphere, and Image 5 and Image 6 play a major role in the sulphur cycle. Depending on the nature of the Lewis bases, the type of interactions between the constituents may alter, which would influence the final product in a chemical reaction, nucleation process, and radiative forcing. The key objective of this work is to understand the plausible interaction between Image 7 and sulphur-containing Lewis bases (Image 8, Image 9), and to identify the propensity towards the formation of hydrogen bond and halogen bond interaction at the molecular level using matrix-isolation FTIR spectroscopy. Electronic structure calculations have been performed in the ground electronic state to predict the possible structures and stability of the clusters. The thermodynamic properties of the dimers have been evaluated along with their higher-order clusters to understand the possibility of forming such complexes in the atmosphere.