Modulating the Amine–CO₂ Interaction Strength: Toward Efficient Carbon Capture

This study contributes to a comprehensive understanding of the interactions between CO₂ and amines at the molecular level by exploring the rotational spectra of binary complexes between CO₂ and eight different amines through pulsed-jet Fourier transform microwave spectroscopy and quantum chemical calculations. The findings reveal a consistent pattern in which CO₂ is bonded to the amino group, primarily through a C···N tetrel bond, while being supported by C-H···O/C hydrogen bonds. Notably, the binding energies increase from primary through tertiary amines and with increasing chain length of the alkyl groups. These groups are found to enhance the electron density at the amino group significantly, thereby facilitating the formation of stronger C···N tetrel bonds. The insights provided into how the interaction strength is modulated by the geometries of amines are deemed essential for the design of more effective CO₂ adsorption materials, thus advancing carbon capture technologies.