The Open‐Chain Trioxide CF₃OC(O)OOOC(O)OCF₃

Abstract

The open-chain trioxide CF(3)OC(O)OOOC(O)OCF(3) is synthesised by a photochemical reaction of CF(3)C(O)OC(O)CF(3), CO and O(2) under a low-pressure mercury lamp at -40 degrees C. The isolated trioxide is a colourless solid at -40 degrees C and is characterised by IR, Raman, UV and NMR spectroscopy. The compound is thermally stable up to -30 degrees C and decomposes with a half-life of 1 min at room temperature. Between -15 and +14 degrees C the activation energy for the dissociation is 86.5 kJ mol(-1) (20.7 kcal mol(-1)). Quantum chemical calculations have been performed to support the vibrational assignment and to discuss the existence of rotamers.

Bis(fluoroformyl)trioxide, FC(O)OOOC(O)F

“…It is the second, but most simple example of a chainlike acyl trioxide after CF 3 OC(O)OOOC(O)OCF 3 , whose structure is still unknown. [12] We observed the formation of FC(O)OOOC(O)F during the synthesis of FC(O)OOC(O)F in molar scale by treating CO with F 2 in the presence of O 2 according to the literature method. [13] The gas-phase pyrolysis of FC(O)OOC(O)F yielded FCO 2 radicals and allowed the measurement of their rotational spectrum.…”

A Systematic Investigation into the Mechanism of the Reaction Between CF3 Radicals and CO/O2

“…A few years later, the isolation of the peroxide CF 3 -OC(O)OOC(O)OCF 3 [19] was achieved. More recently, von Ahsen et al [20] succeeded in synthesizing the trioxide CF 3 OC(O)OOOC(O)OCF 3 at low temperatures.…”

“…Another reaction with acylperoxy radicals is reaction (12), which produces acyloxy radicals. Moortgat et al [9] and Malanca et al, [16] believed in an immediate decarboxylation that would prevent the existence of CF 3 OCO 2 radicals [reaction (13), Table 1]; however, the existence of CF 3 OCO 2 radicals is proven by the formation of the recently isolated trioxide, [20] formed through reaction (14) ( Table 1). It will be seen that our experiments with isotopes (performed at the same temperatures as those of Malanca et al [16] ) confirm that these radicals live long enough to dimerize.…”

“…It is worth highlighting that this reaction, on account of the temperature at which the experiments had been done before, found some reluctance to be accepted and has been taken into account only in recent reports, where lower temperatures were used that enabled the formation of intermediate substances. [19,20] Carbonyl fluoride results mainly from the decomposition of CF 3 O radicals [reaction (16), Table 1 ð14:5Þ Figure 5 shows the IR spectrum resulting from ab initio calculations for the nonmarked isotopomer and CF 3 O 13 - 3 , in addition to the experimental IR spectrum. As can be seen, the correspondence between the calculated and experimental spectra is remarkably good, which is important when trying to rely on calculations to decide what reactions are taking place.…”

“…These features are in agreement with those observed and discussed in the paper reporting the synthesis of the trioxide. [20] The isotopomer with one 18 O atom in the oxygen chain has two different oxygen atoms bonded to the carbonyl, which is reflected in the two calculated bands (second trace from bottom, Figure 6). It can also be observed that , which we ascribe to the pure CÀF stretchings.…”