Transition metal nitric oxide, binding

Thomas, J. L. C., Bauschlicher, C. W., Jr., Hall, M. B., 1997, Binding of Nitric Oxide to First-Transition-Metal-Row Metal Cations. An Ab Initio Study , J. Phys. Chem. A, 101, 8530. 

It was found that the electrocatalytic activity strongly depends on the nature of the electrode it decreases in the order Rh > Ru > Ir > Pd and Pt for the transition-metal electrodes and in the order Cu > Ag > Au for the coinage metals. It was concluded that the rate-determining step on Ru, Rh, Ir, Pt, Cu, and Ag is the reduction of nitrate to nitrite. It was assumed that chemisorbed nitric oxide is the key surface intermediate in the nitrate reduction. It was suggested that ammonia and hydroxylamine are the main products on transition-metal electrodes. This is in agreement with the known mechanism for NO reduction, which forms N2O or N2 only if NO is present in the solution. On Cu the production of gaseous NO was found, which was explained by the weaker binding of NO to Cu as compared to the transition metals. 

The discovery that the nitrosyl ligand is capable of binding to transition metals in two isomeric valence forms1 is one of the most dramatic recent developments in organometallic chemistry. Since bent NO donates 2 fewer electrons to the metal than the linear isomer does, linear-bent tautomerism raises the possibility of coordinative unsaturation and catalysis.2 In fact, complexes of nitric oxide are receiving increasing attention as catalysts,3 since they are more reactive than the corresponding carbonyls.4... 

Nitric oxide fixation by non-transition metal complexes was reported by Ilyakina et al. [98]. Lead(II) and zinc(II) catecholato complexes readily react with nitric oxide to give the corresponding nitrosyl-containing mono-o-semiquinonates the process of binding and transfer of NO was monitored by EPR spectroscopy [98]. 

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