Untitled

Bond Formation with Maintenance of Twofold Charge: Generation of C2O32+ in the Reaction of CO22+ with CO2

“…[1,2] However, C 2 O 3 has not been isolated as a bulk compound, and thermodynamic considerations of Perk and Liebman suggest that oxirandione is approximately 230 kJ mol À1 less stable than the separated fragments CO and CO 2 . [3] This prediction is in good agreement with a computed exothermicity of 222 kJ mol À1 for the dissociation of cyclic C 2 O 3 into CO and CO 2 , as reported by Peppe et al [4] in their attempts to generate neutral C 2 O 3 from appropriate ionic species using neutralization-reionization mass spectrometry. [5] In addition to the weakly bound van der Waals complex [CO·CO 2 ], the trioxapropellane structure of C 2 O 3 has received attention in a number of theoretical studies.…”

“…On the basis of two arguments, we propose 3 2 2+ as an intermediate in the formation of C 2 O 3 2+ according to Equation (1). The CO 2 2+ dication has a triplet ground state, [24] and a spin-conserving channel [25,26] is more likely to be able to kinetically compete with exothermic single-electron transfer.…”

“…The ground state of CO 2 2+ ( 3 AE g À ) has two unpaired electrons localized at the oxygen atoms, and the analysis of the spin density of 3 2 2+ suggests that the unpaired electrons stay at these oxygen atoms (Figure 4), whereas the positive charge is delocalized over the whole skeleton of C 2 O 4 2+ . It follows that the dominant route for the dissociation of 3 2 2+ into C 2 O 3 2+ + O involves homolytic cleavage of the CÀO bond to an oxygen atom that bears an unpaired electron (pathway a in Figure 4), thereby accounting for the preferential elimination of an oxygen atom stemming from the original CO 2 2+ dication, as observed experimentally. Other scenarios are less probable (pathways b and c in Figure 4) oxygen atoms or even preferential O-atom loss from neutral CO 2 would be expected.…”

“…It follows that the dominant route for the dissociation of 3 2 2+ into C 2 O 3 2+ + O involves homolytic cleavage of the CÀO bond to an oxygen atom that bears an unpaired electron (pathway a in Figure 4), thereby accounting for the preferential elimination of an oxygen atom stemming from the original CO 2 2+ dication, as observed experimentally. Other scenarios are less probable (pathways b and c in Figure 4), because they lead to less stable isomers of C 2 O 3 2+ ( 1 4 2+ , 3 4 2+ , 1 5 2+ , and 3 5 2+ ). Moreover, with these routes, scrambling of the oxygen atoms or even preferential O-atom loss from neutral CO 2 would be expected.…”

Bindungsbildung unter Erhalt der zweifachen Ladung: Erzeugung von C2O32+ aus CO22+ und CO2

“…230 kJ mol À1 instabiler als die getrennten Fragmente CO + CO 2 . [3] Dieser Wert stimmt mit einer berechnteten Exothermie von 222 kJ mol À1 für den Zerfall von cyclischem C 2 O 3 in CO + CO 2 gut überein, die Peppe et al [4] bei Versuchen zur Erzeugung von neutralem C 2 O 3 aus geeigneten ionischen Vorstufen mithilfe der Neutralisations-Reionisations-Massenspektrometrie [5] ermittelten. Zusätzlich zu dem schwach gebundenen Van-der-Waals-Komplex [CO·CO 2 ] ist auch die Trioxapropellan-Struktur von C 2 O 3 in einer Reihe theoretischer Arbeiten betrachtet worden.…”