Molybdenum and tungsten, dinitrogen complexes

An in situ 15N-NMR study of the protonation reactions of molybdenum and tungsten dinitrogen complexes has shown that signals arise in the early stages of the reaction which can be assigned to relatively stable hydrazido(2-) species (4). With careful choice of acid and conditions, thermally stable hydrazido(2-) complexes can be isolated. They often yield ammonia and/or hydrazine upon further protonation (4,105), for example, reaction (43). 

Hidai and Chatt thoroughly studied the reactivity of molybdenum and tungsten dinitrogen complexes with various phosphine hgands such as the bidentate derivatives dppe (where dppe = Ph2PCH2CH2PPh2) or depe (where depe =Et2PCH2CH2PEt2) for synthetic dinitrogen fixation. 

Hidai M, Komori K, Kodama T, et al. Preparation and properties of molybdenum and tungsten dinitrogen complexes XXL Trimethylsilylation of coordinated dinitrogen. J Organomet Chem. 1984 272 155-167. 

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