Nitrido Complexes of Transition Metals

In the past decade new syntheses and numerous structural determinations have enlivened studies in the still relatively young field of nitrido-transition-metal complexes. Aside from the terminal function of the nitrido ligand M?N:, this group also occurs as linear μ₂-bridging ligand in symmetric and asymmetric coordination; examples are known with almost right-angled bridge function; and, finally, it also functions as μ₃-bridging ligand. Accordingly, the fresh impulses given to synthetic chemistry by nitrido complexes are also many-sided: such complexes are used, inter alia, for the preparation of phosphaniminato and thionitrosyl complexes as well as for the synthesis of metallaheterocycles of the type MN₃S₂ and MN₃P₂ with delocalized π-systems. In technetium chemistry complexes with terminal nitrido group are employed as radiopharmaceuticals, and, owing to the strong trans influence of the M?N: group, nitrido complexes of molybdenum are suitable as catalysts in olefin metathesis. Finally, nitrido complexes are also of wide interest in theoretical studies.