Reactivity of Hydrated Monovalent First Row Transition Metal Ions M+(H2O) n , M = V, Cr, Mn, Fe, Co, Ni, Cu, Zn, toward Molecular Oxygen, Nitrous Oxide, and Carbon Dioxide

The reactions of hydrated monovalent transition metal ions M+(H2O) n , M = V, Cr, Mn, Fe, Co, Ni, Cu, Zn, toward molecular oxygen, nitrous oxide, and carbon dioxide were studied by Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry. Clusters containing monovalent chromium, cobalt, nickel, or zinc were reactive toward O2, while only hydrated cobalt was reactive toward N2O. A strongly size dependent reactivity was observed. Chromium and cobalt react very slowly with carbon dioxide. Nanocalorimetric analysis, 18O2 exchange, and collision induced dissociation (CID) experiments were done to learn more about the structure of the O2 products. The thermochemistry for cobalt, nickel, and zinc is comparable to the formation of O2 – from hydrated electrons. These results suggest that cobalt, nickel, and zinc are forming M2+/O2 – ion pairs in the cluster, while chromium rather forms a covalently bound dioxygen complex in large clusters, followed by an exothermic dioxide formation in clusters with n ≤ 5. The results show that hydrated singly charged transition metal ions exhibit highly specific reactivities toward O2, N2O, and CO2.