Platinum dioxide cation: Easy to generate experimentally but difficult to describe theoretically

A formal platinum(V) dioxide cation [Pt,O-2](+) can be generated in the gas phase by successive oxidation of Pt+ with N2O. The ion's reactivity is in keeping with the dioxide structure OPtO+, rather than with [Pt,O-2](+) isom ers having intact O-O bonds, e.g., the dioxygen complex Pt(O-2)(+) and pero xo species PtOO+. inter alia due to the high ionization energy of the neutr al counterpart (11.2 eV), the [Pt,O-2](+) cation is a rather aggressive rea gent toward oxidizable neutrals. [Pt,O-2](+) is even capable of activating inert substrates such as H-2, CO, and CH4 Further, a sequence for the catal ytic conversion CO + N2O --> CO2 + N-2 is described with a turnover number of > 100 for the catalytically active species PtOn+ (n = 0-2). As a consequ ence of the high reactivity, however, the observed selectivities with most substrates are rather poor. For example, the reaction of PtO2+ with ethane gives rise to 10 different product channels, in an attempt to analyze the s tructural features and different minima of the [Pt,O-2](+) system, extensiv e ab initio studies are performed. While correlated ab initio methods descr ibe the system reasonably well, density functional theory turns out to be m uch less accurate in terms of both structural and energetic descriptions.