Design, synthesis and reactivity of dimolybdenum complex bearing quaterphenylene-bridged pyridine-based PNP-type pincer ligand.

Dimolybdenum complexes bearing 3,3'''-(1,1':3',1'':3'',1'''-quaterphenylene)-bridged pyridine-based PNP-type pincer ligand are designed and prepared according to DFT calculations on the cleavage step of dinitrogen-bridged dimolybdenum complexes bearing polyphenylene-bridged pyridine-based PNP-type pincer ligands. The dimolybdenum complexes are found to work as effective catalysts toward ammonia formation from dinitrogen with samarium diiodide as a reductant and water as a proton source under ambient reaction conditions.

Catalytic Reactivity of Molybdenum-Trihalide Complexes Bearing PCP-Type Pincer Ligands.

Molybdenum-iodide complexes bearing a PCP[1] ligand have been found to work as excellent catalysts toward ammonia formation under ambient reaction conditions among dinitrogen-bridged dimolybdenum complexes and other molybdenum complexes bearing PNP and PCP[2] ligands.

Effect of substituents on molybdenum triiodide complexes bearing PNP-type pincer ligands toward catalytic nitrogen fixation.

Molybdenum triiodide complexes bearing various substituted pyridine-based PNP-type pincer ligands are prepared and characterized by X-ray analysis. Their catalytic activity is investigated toward the reduction of nitrogen gas into ammonia under ambient reaction conditions.

Synthesis and reactivity of titanium- and zirconium-dinitrogen complexes bearing anionic pyrrole-based PNP-type pincer ligands.

Dinitrogen-bridged dititanium and dizirconium complexes bearing anionic pyrrole-based PNP-type pincer ligands are prepared and characterized by X-ray analysis. Their catalytic activity is investigated toward reduction of nitrogen gas into ammonia and hydrazine under mild reaction conditions.

Catalytic Reduction of Molecular Dinitrogen to Ammonia and Hydrazine Using Vanadium Complexes.

Newly designed and prepared vanadium complexes bearing anionic pyrrole-based PNP-type pincer and aryloxy ligands were found to work as effective catalysts for the direct conversion of molecular dinitrogen into ammonia and hydrazine under mild reaction conditions. This is the first successful example of vanadium-catalyzed dinitrogen reduction under mild reaction conditions.

Preparation and reactivity of iron complexes bearing anionic carbazole-based PNP-type pincer ligands toward catalytic nitrogen fixation.

Iron-chloride, -dinitrogen, and -methyl complexes bearing anionic carbazole-based PNP-type pincer ligands are designed, prepared and characterized by X-ray analysis. Some iron complexes are found to work as catalysts toward nitrogen fixation under mild reaction conditions.

Synthesis and reactivity of iron-dinitrogen complexes bearing anionic methyl- and phenyl-substituted pyrrole-based PNP-type pincer ligands toward catalytic nitrogen fixation.

Iron-dinitrogen complexes bearing methyl- and phenyl-substituted pyrrole-based anionic PNP-type pincer ligands are prepared and characterized by X-ray analysis. The former complex is found to work as a more effective catalyst than that bearing a non-substituted PNP-type pincer ligand toward the transformation of nitrogen gas into ammonia and hydrazine under mild reaction conditions.

Remarkable catalytic activity of dinitrogen-bridged dimolybdenum complexes bearing NHC-based PCP-pincer ligands toward nitrogen fixation.

Intensive efforts for the transformation of dinitrogen using transition metal-dinitrogen complexes as catalysts under mild reaction conditions have been made. However, limited systems have succeeded in the catalytic formation of ammonia. Here we show that newly designed and prepared dinitrogen-bridged dimolybdenum complexes bearing N-heterocyclic carbene- and phosphine-based PCP-pincer ligands [{Mo(N2)2(PCP)}2(µ-N2)] (1) work as so far the most effective catalysts towards the formation of ammonia from dinitrogen under ambient reaction conditions, where up to 230 equiv. of ammonia are produced based on the catalyst. DFT calculations on 1 reveal that the PCP-pincer ligand serves as not only a strong σ-donor but also a π-acceptor. These electronic properties are responsible for a solid connection between the molybdenum centre and the pincer ligand, leading to the enhanced catalytic activity for nitrogen fixation.

Catalytic reduction of dinitrogen to ammonia by use of molybdenum-nitride complexes bearing a tridentate triphosphine as catalysts.

Newly designed and prepared molybdenum-nitride complexes bearing a mer-tridentate triphosphine as a ligand have been found to work as the most effective catalysts toward the catalytic reduction of dinitrogen to ammonia under ambient conditions, where up to 63 equiv of ammonia based on the Mo atom of the catalyst were produced.