Nitrogen bond lengths, metal

Two types of NO coordination to ruthenium are known linear Ru-N—O 180° and bent, Ru-N-O 120°. Since NO+ is isoelectronic with CO, linear Ru-N-O bonding is generally treated as coordination of NO+, with bent coordination corresponding to NO- thus, in the former an electron has initially been donated from NO to Ru, as well as the donation of the lone pair, whereas in the latter an electron is donated from the ruthenium to NO (making it NO-) followed by donation of the lone pair from N. Though an oversimplification, this view allows a rationale of metal-nitrogen bond lengths, as with the Ru—NO+ model 7r-donation is important and a shorter Ru—NO bond is predicted - and, in fact, observed. 

Metal-Nitrogen Bond Lengths and Torsion Angles between the Metal and Nitrogen Coordination Planes for Three-Coordinate Aluminum, Gallium, Indium, and Thallium Amides... 

Table 8.1 Metal-nitrogen bond lengths in isoleptic aluminium and gallium amides...

There is an extensive literature on ammines and the Chemical Abstracts 10th Collective Index (1977-81) has four pages under this heading. One important parameter for this class of compound is the metal-nitrogen bond length and Table 1 lists some of the available data. Transition metal-NH, bond energies have also been calculated.100... 

In the molybdenum-nitrogen four-membered ring, the metal-nitrogen bond lengths alternate (1.67 and2.17A). 

Consideration of metal-nitrogen bond lengths in light of the ionic-bonding model advanced by Raymond (10) leaves little doubt that the bonding in the binary silylamide derivatives of the lanthanide elements is predominantly ionic (11). Indeed, all of the tris-silylamide derivatives of the p-, d-, and f-block elements can be viewed as being mainly ionic. 

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