Molybdenum complexes nitrogen bonds

The formation of 2H-pyrroles (21) and a pyrrole derivative (22) from the reaction of 3-phenyl-2//-azirines and acetylenic esters in the presence of molybdenum hexacarbonyl is intriguing mechanistically (Schemes 24, 25).53 Carbon-nitrogen bond cleavage must occur perhaps via a molybdenum complex (cf. 23 in Scheme 26) but intermediate organometallic species have not yet been isolated.53 Despite the relatively poor yields of 2H-pyrrole products, the process is synthetically valuable since the equivalent uncatalyzed photochemical process produces isomeric 2H-pyrroles from a primary reaction of azirine C—C cleavage54 (Scheme 24). 

Complexes Involving Multiple Molybdenum-Nitrogen Bonds 1340... 

Cummins complex Mo(NRAr)3 is an interesting one, because it allows both the formation of a dinitrogen complex and the cleavage of the very strong nitrogen-nitrogen bond in N2 (942 kJ mol ) at room temperature to form two nitrogen-molybdenum triple bonds (680 kJ- mol each) ... 

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