Gas‐phase reactions of transition metal carbonyl anions and atomic metal anions with nitrous oxide and dioxygen: Oxygen atom transfer and ligand exchange in reactions with nitrous oxide

Abstract

AbstractThe gas‐phase reactions of a series of metal carbonyl anions M(CO) (M=Cr, n=2–5; M=Mn, n=1–5; M=Fe, n=1–4) with nitrous oxide and dioxygen have been studied by use of Fourier‐transform ion cyclotron resonance (FTICR) mass spectrometry. With nitrous oxide, most of the metal carbonyl ions react by oxygen atom transfer leading to oxo‐metal anions and oxo‐metal carbonyl anions. The Cr− and Fe− ions also react relatively easily with nitrous oxide by oxygen atom abstraction to form CrO− and FeO−, respectively. Experiments with N15NO reveal that loss of a CO molecule from a collision complex is a significant ligand exchange channel for the Mn(CO), Mn(CO) and Fe(CO) ions. The nitrous oxide molecule remains intact in the resultant product ions, M(CO)n(N2O)− with M=Mn, n=2 and 3; and M=Fe, n=2. The losses of 15NN and 15NN + CO in the collision‐induced dissociations of the Mn(CO)3(N15NO)− ions, in combination with the relatively facile occurrence of oxygen atom transfer, are taken to mean that coordination of the metal centre to the oxygen atom is preferred over bond formation to the terminal nitrogen atom of the nitrous oxide molecule. The metal carbonyl anions react readily with dioxygen to form mainly oxo‐metal ions as well as oxo‐ and dioxo‐metal carbonyl anions in relative yields which depend on the nature of the metal and the number of CO ligands in the reactant ion.