Computational Investigation of the Preferred Binding Modes of NO in Group 8 Metal Complexes.

Nitrous oxide (NO) is a potentially important oxidant for green chemistry applications but thus far has shown limited examples as a ligand for transition metal complexes. Given the lack of reported NO complexes, density functional theory was utilized to study the potential binding effects in multiple group 8 metal complexes. NO is found to be a very weakly π-accepting ligand (approximately 1/3 as effective as CO). With the weak π-accepting character, the NO is predicted to be bound through the nitrogen atom in a linear geometry. In all calculated ruthenium and osmium complexes, the nitrogen bound mode of binding is preferred. Only by introduction of a very weak π-donor metal (such as iron) can the NO be found to slightly prefer binding through the oxygen atom in a purely σ-donor fashion.