Chlorine "Equatorial Belt" Activation of CF3Cl by CO2: The C···Cl Tetrel Bond Dominance in CF3Cl-CO2.

Besides its typical halogen donor behavior (exhibiting a Cl σ-hole) in forming Cl···B halogen bonds (B is an electron-rich region), CF3Cl reveals a new interaction site in its complex with CO2 when explored by rotational spectroscopy. Experimental evidence and theoretical analyses point out irrefutably that CF3Cl prefers to link to CO2 through its Cl "equatorial belt" consisting of the lone pairs of the Cl atom, resulting in a C···Cl tetrel bond. In addition, a secondary plausible C···O tetrel bond and a F···O halogen bond might contribute to the relative orientation of the moieties forming the complex. The effects of the Cl "equatorial belt" present in perhalogenated molecules, such as CF3Cl, have been hitherto overlooked in describing the origin of noncovalent interactions. That left a significant void that the present study tries to fill by outlining its importance.