Side-on end-on bound dinitrogen: an activated bonding mode that facilitates functionalizing molecular nitrogen

Area of Science:

• Inorganic Chemistry
• Catalysis
• Organometallic Chemistry

Background:

• Molecular nitrogen (N2) is essential for life but inert, making its conversion challenging.
• Current nitrogen fixation methods (biological and industrial) are energy-intensive.
• Discovering homogeneous catalysts for N2 conversion is a long-standing goal.

Purpose of the Study:

• To explore a new, milder pathway for generating dinitrogen complexes.
• To investigate the reactivity of a novel dinitrogen complex with various hydride reagents.
• To assess the potential for a catalytic cycle to produce higher-value nitrogen compounds.

Main Methods:

• Reaction of dinitrogen with a ditantalum tetrahydride species.
• Synthesis of the dinitrogen complex ([NPN]Ta)(2)(mu-H)(2)(mu-eta(1):eta(2)-N(2)).
• Treatment of the dinitrogen complex with hydride reagents (R2BH, R2AlH, RSiH3, Cp2ZrCl(H)).

Main Results:

• A facile reaction generated an unusual side-on end-on bound N2 moiety.
• The dinitrogen complex underwent N-N bond cleavage upon reaction with hydride reagents.
• Various functionalized imide and nitride moieties were formed.
• The potential catalytic cycle for generating higher-value nitrogen materials was evaluated.

Conclusions:

• A new method for generating dinitrogen complexes under milder conditions was demonstrated.
• The reactivity of the novel dinitrogen complex expands understanding of coordinated N2 chemistry.
• While direct catalytic cycles for higher-value products were not fully realized with tested reagents, the fundamental reactivity offers a basis for future catalyst design.