Formation, Structure, and Reactivity of Gaseous Ni₂O₂⁺

Abstract

The dinuclear metal dioxide Ni2O2+ is prepared by the reaction of gaseous Ni2+ with N2O in a Fourier‐transform ion‐cyclotron‐resonance (FT‐ICR) mass spectrometer. The title compound oxidizes CO, thus proving the catalytic activity of Ni2+ for mediating oxygen‐atom transfer from N2O to CO. Whereas Ni2O2+ does not react with H2 and CH4, it accomplishes C–H bond activation of ethane, propane, and n‐butane. In comparison to the previously studied metal‐oxide clusters Mn2O2+ and Fe2O2+, Ni2O2+ exhibits an enhanced reactivity, which is ascribed to a lower oxygen‐binding energy. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

Gas‐Phase Model Studies Relevant to the Decomposition of Transition‐Metal Nitrates M(NO3)2 (M = Co, Ni) into Metal–Oxo Species

“…In addition, however, a series of cluster ions is formed under these conditions in appreciable yields, which can compete with other, more complicated approaches for the generation of Co m O n +/-cluster ions. [43][44][45][46] Particularly noteworthy is that the use of cobalt(II) nitrate as a precursor allows the generation of oxygen-rich [47] and Ni 2 O 2 + (m/z = 148), [48] which have already been shown to be able to act as oxidation reagents in the gas phase. However, rather than Ni m O n + formation, the nickel system displays a significantly higher tendency to yield bare, unsolvated nitrato clusters of the type [Ni m + (m/z = 302 for the 58 Ni isotope), [Ni 3 (11)].…”

Gas‐Phase Reactions of Homo‐ and Heteronuclear Clusters MM′+ (M, M′=Fe, Co, Ni) with Linear Alkanenitriles

“…The ion/molecule reactions of trapped cluster ions with the nitriles were then studied by leaking-in the neutral substrates at stationary pressures of the order of 10 À8 mbar. Concerning the thermalization of the cluster cations, several observations reported in the present work and detailed investigations on Ni-cluster oxides [12] suggest that some electronically excited Ni 2 generated in the cluster source possibly survive the thermalization. This is supported by the observation of some reactions which are clearly endothermic for ground-state Ni 2 and should, therefore, not take place at ambient temperature.…”

MRCI investigation of different isomers of Ni2O2H2+

“…The majority of the low-lying terms can be grouped into spin ladders with three nearly equidistant levels (2S + 1 = 2,4,6), the lowest one being a sextet term. The 2 B 1u and 4 A g terms are an exception. The low-lying sextet terms of the further spin ladders are the 6 A u term at a relative energy of only 0.004 eV with respect to the 6 B 1g term and furthermore 6 A g at about 0.02 eV, 6 B 2u and 6 B 3g at about 0.04 eV, and 6 B 3u and 6 B 2g at about 0.10 eV.…”

“…The low-lying sextet terms of the further spin ladders are the 6 A u term at a relative energy of only 0.004 eV with respect to the 6 B 1g term and furthermore 6 A g at about 0.02 eV, 6 B 2u and 6 B 3g at about 0.04 eV, and 6 B 3u and 6 B 2g at about 0.10 eV. The other two terms that form the lowest-lying spin ladder together with the 6 B 1g term are 4 A u and 2 B 1g at 0.09 and 0.17 eV. The splitting of the different spin ladders, defined as the difference in energy between the doublet and the sextet terms, varies between values of 0.17 and 0.20 eV.…”

“…Solely, it is assumed that Ni 2 (OH) 2 + or Ni 2 O(H 2 O) + structures seem most likely. 4 Therefore, to continue the study of the reaction of Ni 2 O 2 + , quantum chemical calculations are performed to characterise the lowlying states of different isomers of Ni 2 O 2 H 2 + . The investigation relies on multireference configuration interaction (MRCI) calculations, because a multireference treatment is advised anyway due to the open shell character of the Ni atoms and since the aim is to characterise different low-lying excited states, for which multireference characters are still more likely.…”