Tetrel bonds and conformational equilibria in the formamide–CO2 complex: a rotational study†
Abstract
The rotational spectra of the complex formamide–CO2 have been measured and assigned by pulsed jet Fourier transform microwave spectroscopy. Two isomers of the complex have been detected where a C⋯O tetrel bond dominates the interactions, and either N–H⋯O or C–H⋯O forms a secondary linkage. Bader's quantum theory of atoms in molecules and Johnson's non-covalent interaction analyses were applied to unveil the intermolecular binding sites and energetic properties in the complex. Relative intensity measurements on a set of μa-type transitions allowed estimating the relative population of the observed two isomers as NI/NII ≈ 18/1.