“…[6] Thei ntermediates were well characterized, and the catalytic cycle of this reaction was established to be aMo III -Mo VI cycle,which is now known as the Schrock cycle.M any landmark studies of N 2 fixation have also been performed in the development of reactions for catalytic ammonia synthesis in the presence of proton sources and reductants by using transition-metal complexes [1,6,7] Since the direct cleavage of the extremely strong N 2 triple bond (BDE = 226 kcal mol À1 )b yl ow-coordinate and electron-rich transition-metal complexes was first reported by Laplaza and Cummins, [8] investigations of the cleavage of the N 2 triple bond through thermal, chemical, and photochemical reactions have been carried out. Regarding N 2 cleavage by Mo I complexes supported with at ridentate ligand and halogen as intermediates, [1i, [28][29][30] the groups of Schrock, MØzailles,and Nishibayashi have reported that aMo III complex is used as aprecursor for the synthesis of anitride complex. Thereduction of the precursor is promoted by addition of as trong reductant to generate the Mo I complex, and then the Mo IV nitride complex is synthesized by formation of ad imeric Mo complex with ab ridging N 2 molecule in the subsequent reaction.…”