Redox transformations of N-donor ligands

In 1895, Hofmann studied the reduction of coordinated nitrosyl groups. The interaction of sodium nitroprusside with hydrazine in an aqueous solution of NaOH formed the corresponding aqua-complex with the explosive liberation of dinitrogen. The overall process is described by Eq. 3.10  

Additionally, Hofmann s work showed that the reaction of sodium nitroprusside with hydroxylamine leads to formation of Na3lFe(CN)5(H20)] and to generation of nitrous oxide. The kinetics of this reaction have been discussed by several workers. 7,48 Based on the experimental data reported, the process appears to begin with nucleophilic attack on the coordinated nitrosyl ligand by the hydroxylamine N-atom. Then, the decomposition of the resultant intermediate leads to formation of nitrous oxide and the aqua-complex. 

Interaction between nitrosyl ligands and hydroxylamine is not limited to reactions with sodium nitroprusside. For example, reaction49 with K[IrXs(NO)] (X = Cl, Br) in aqueous solution results in formation of [IrX5(H20)]2- aqua-complexes and liberation of N2O. 

Azide ion also enters into redox interactions with linear nitrosyls. The 

More recently it has been established that the affinity of acetone for ruthenium(II) in [RuCl(bipy)2(Me2CO)]+ is so weak that, over time, the compound, in an acetone-methanol solvent mixture, spontaneously eliminates the solvento-ligand and dimerization of the coordinatively unsaturated intermediate occurs, Eq. 3.12  

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