Predicting Dinitrogen Activation and Coupling with Carbon Dioxide and Other Small Molecules by Methyleneborane: A Combined DFT and Machine Learning Study

The capture of carbon dioxide is extremely important
due to the
increasingly severe greenhouse effect, and the conversion of dinitrogen
into high-value N–C compounds is of great significance. Here,
we predict through density functional theory calculations that the
coupling of dinitrogen with carbon dioxide by methyleneborane becomes
favorable both thermodynamically and kinetically. Machine learning
analysis suggests that increasing the HOMO–LUMO gap or the
charge on the boron atom or decreasing the charge of the nitrogen
atom will reduce the reaction energies. N2 coupling is
examined as a concerted step, as CO2 is a σ donor
and a π acceptor. Besides, N2 coupling with other
small molecules including formaldehyde, sulfur dioxide, acetonitrile,
and N-ethylidenemethylamine was also examined in
both thermodynamics and kinetics. Our findings highlight a crucial
role of main group species in N2 coupling chemistry.