Sp 2 - and sp 3 -C⋯O tetrel bonds in the 3-oxetanone homodimer.

The structures and non-covalent interactions at play in the 3-oxetanone homodimer have been investigated using a pulsed jet Fourier transform microwave spectrometer supplemented with quantum chemical calculations. Two isomers were identified in the pulsed jet. With the analyses of non-covalent intermolecular interactions including the quantum theory of atoms, Johnson's non-covalent interactions and natural bond orbital, the observed global minimum is stabilized by a combination of one sp 2 -C⋯O tetrel bond and a network of multiple C-H⋯O weak hydrogen bonds. The second isomer is characterized by carbonyl-carbonyl interactions, with the formation of one sp 2 - and one sp 3 -C⋯O tetrel bond. The conformational population of the two observed isomers in the supersonic expansion was estimated to be N CE1 / N CC1 ≈ 7/5.