Structural Characterisation of Nitrosyl Complexes

101° to 134° both dimensions depend on the electronegativities of the substituents. Substituent effects also influence v(NO), which lies between 1,621 and 1,363 cm [26]. 

In low-spin d octahedral complexes, e. g. [Cr(NO)(NH3)5], the depopulation of the t2g orbitals does not change the bond lengths associated with the metal-nitrosyl moiety greatly [41], The M-N-O bond angle is symmetiy imposed at 180°, the M-N(O) bond is 0.9 A shorter than the cis bonds to the amine ligands and the tram influence is 0.09 A. In these complexes, the multiple bmid character associated with and dy is retained, and the odd electron resides in the nmilxHidtng d orbital. 

The jr-bonded nitrosyl ligand has been structurally characterised in metastable excited states of some complexes, e.g. [Ni(NO)(q-CsMe5)], by Coppens et al. [21,50, 51], and they have the disorder shown in 14. This research has taken on a special relevance with the appearance of a side-rai nitrosyl in the structural determination of the native enzyme in bacterial Alcaligenes faecalis CuNIR [52, 53] but has not yet been duplicated in model copper complexes. This remains a synthetic challenge for future model studies [54]. Coppens [21] also structurally characterised metastable 

There is one minor point of difference which is noteworthy. In terms of electron counting, carbonyl clusters have bridges which are formally associated with a 

Recently the first examples of nitrosyl complexes of the lanthanides and actinides have been reported by Evans and co-workers, and they are illustrated in 

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