Cooperative Ammonia Formation Catalyzed by Molybdenum and Samarium Complexes

Newly designed samarium complexes bearing chelate-type cyclopentadienyl-amide ligands have been found to work as effectively cooperative catalysts with molybdenum complexes bearing PCP-type pincer ligands toward ammonia formation from dinitrogen under ambient reaction conditions. In this reaction system, the samarium complexes accelerate the transfer of protons and electrons from the terminal proton source and reductant to molybdenum–nitride, –imide, and –amide complexes as reactive intermediates, resulting in ammonia in excellent yields with high rates of ammonia formation. Results of cyclic voltammograms and DFT calculations support PCET catalysts for the samarium complexes.