Synthesis and properties of trifluoromethoxyl fluoroformyl anhydride, CF3OC(O)OC(O)F

In the present work the synthesis of the trifluoromethoxyl fluoroformyl anhydride is presented for the first time. Two strategies were employed to obtain CF3OC(O)OC(O)F: the thermal decomposition of CF3OC(O)OOOC(O)F in excess of CO, and the reaction between CF3OC(O)OOC(O)F, FC(O)OOC(O)F and CO. A mechanism was proposed taking into account reaction rates and thermal stability of the intermediates. DFT calculations at B3LYP/6-311+G* level were used to explore the conformational space of this molecule and the relative populations of conformers at room temperature, and to simulate the experimental vibrational spectrum. This molecule completes the family of the asymmetric oxygen bonded acyl compounds CF3OC(O)OxC(O)F with x = 1–3.

The pictogram represents the formation of the anhydride CF3OC(O)OC(O)F from the reaction of the trioxide CF3OC(O)OOOC(O)F with CO (left) and from the peroxides CF3OC(O)OOC(O)F, FC(O)OOC(O)F and CO (right). The colour code for the atoms is at the left corner.Figure optionsDownload as PowerPoint slideHighlights
► The synthesis, IR spectroscopy and DFT calculations of the new perfluorinated anhydride, CF3OC(O)OC(O)F, are presented.
► The new molecule completes the family of the asymmetric oxygen bonded acyl compounds CF3OC(O)OxC(O)F with x = 1–3.
► A mechanism explaining the formation of the target molecule from the combination of CF3OC(O)Ox and FCOx radicals is discussed.