Nitrido compounds with

Basic ligand-field considerations predict the following energetic order of valence (i-orbitals for six-coordinate iron-nitrido compounds with approximate 4 sym-... 

Nitric anhydride, 3 78 Nitric oxide [see Nitrogen (II) oxide] Nitrido compounds with osmium, 6 204... 

The nitrido compound is very stable and only slightly soluble and thus this reaction provides access to some alkylidyne compounds not readily accessible by the reaction with alkynes, e.g., (Me3CO)3W=CPh. The solid (Me3CO)3W=N has a linear polymeric structure167 in which the WNWN chains have alternating W-N distances of 1.74(1) A and 2.66(1) A. 

The N—N bonds of N2 can be cleaved at room temperature on interaction with some 3-coordinate transition metal complexes6 having bulky ligands. The planar molybdenum complex, Mo(NR R")3, R = C(CD3)2Me, R" = 3,5-C6H3Me2, designated M0L3, appears to react as follows to give a nitrido compound. 

Most Mnv chemistry involves oxo compounds and these are discussed in the next section. Nitrido compounds41 with Mn=N bonds are commonly made by photolysis of azide precursors ... 

An entirely new class which has been discovered and investigated in the last decade are those based on MN f tetrahedra. In some the tetrahedra are discrete79 while in others they are linked by shared N atoms.80 The tetrahedra are isoelectronic with the MO2, ions, but these nitrido compounds are highly sensitive to water. They are made by high-temperature (> 600°C) bomb reactions of the metals with alkali or alkaline earth amides. 

The chemistry of ruthenium and osmium bears little resemblance to that of iron except in compounds such as sulfideror phosphides, and in complexes with ligands such as CO, PR3, or A5-C5H5. The higher oxidation states, VI and VIII, are much more readily obtained than for iron and there is an extensive and important chemistry of the tetraoxides, M04, oxohalides and oxo anions. There are analogies between the chemistries of Ru, Os and Re especially in oxo, nitrogen and nitrido compounds. 

In other systems, N—cleavage gives bis(/i-nitrido)dimetal diamond cores as the products of N2 cleavage. A reduced niobium complex of calix[4]arene reduces N2 in the presence of sodium metal, and a number of intermediates can be isolated. A related tridentate aryloxide ligand also splits N2 to give a diamond core with lithium ions bound to the nitrides. A vanadium diamidoamine complex reacts with N2 to give a product with a similar core structure, which may be further reduced by potassium graphite to a compound with one unpaired electron. This... 

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