CO assisted N2 functionalization activated by a dinuclear hafnium complex: a DFT mechanistic exploration

Area of Science:

• Organometallic Chemistry
• Computational Chemistry
• Catalysis

Background:

• Nitrogen (N2) fixation remains a significant challenge in chemistry.
• Dinuclear hafnium complexes show potential for activating N2.
• Carbon monoxide (CO) can assist in N2 functionalization reactions.

Purpose of the Study:

• To elucidate the reaction mechanisms of CO-assisted N2 cleavage and functionalization.
• To investigate the role of a dinuclear hafnium complex in these transformations.
• To provide theoretical insights into C-N bond formation and N-N bond cleavage.

Main Methods:

• Density Functional Theory (DFT) calculations were employed.
• Analysis of reaction pathways and key intermediates.
• Investigation of coordination structures (axial/equatorial N=C=O).

Main Results:

• Identified crucial intermediates (Ia, Ib, Ic, Id) with N=C=O coordination.
• Two distinct pathways for the first CO insertion into Hf-N bonds were observed.
• Path A1 (CO insertion into Hf(1)-N(3)) is more favorable than Path A3.
• Two pathways (A1 and A2) can lead to final dinitrogen functionalized products (oxamidides 2A, 2B, 2C).

Conclusions:

• The study provides a profound theoretical understanding of CO-assisted N2 functionalization.
• The findings explain the formation of different oxamidide isomers.
• The dinuclear hafnium complex effectively activates N2 for functionalization via CO assistance.