C–F bond activation of trifluoroethanol and trifluoroacetic acid catalysed by the dimolybdate anion, [Mo2O6(F)]−†. Issue 1 (February 2018)

• Record Type: Journal Article
• Authors: Khairallah, George N; Waters, Tom; Wedd, Anthony G; O'Hair, Richard AJ
• Is Part Of: European journal of mass spectrometry. Volume 24:Issue 1(2018)
• Page Start: 43
• Page End: 48
• Publication Date: 2018-02
• Subjects: Dimolybdate -- trifluoroethanol -- trifluoroacetic acid -- C–F bond activation -- gas-phase -- mass spectrometry; Mass spectrometry -- Periodicals; Mass Spectrometry; Mass spectrometry; Periodicals; Periodicals; 543.6505
• DOI: 10.1177/1469066717729250
• Languages: English
• ISSNs: 1469-0667

Abstract

Two gas-phase catalytic cycles involving C–F bond activation of trifluoroethanol and trifluoroacetic acid were detected by multistage mass spectrometry experiments. A binuclear dimolybdate centre [Mo2 O6 (F)] − acts as the catalyst in each cycle. The first cycle, entered via the reaction of [Mo2 O6 (OH)] − with trifluoroethanol and elimination of water to form [Mo2 O6 (OCH2 CF3 )] −, proceeds via four steps: (1) oxidation of the alkoxo ligand and its elimination as aldehyde; (2) reaction of [Mo2 O5 (OH)] − with trifluoroethanol and elimination of water to form [Mo2 O5 (OCH2 CF3 )]; (3) decomposition of the alkoxo ligand via loss of 1, 1 difluoroethene; and (4) reaction of [Mo2 O6 (F)] − with a second equivalent of trifluoroethanol to regenerate Mo2 O6 (OCH2 CF3 )] − . Steps (2) and (3) do not occur at room temperature and require collisional activation to proceed. The second cycle is entered via the reaction of [Mo2 O6 (OH)] − with trifluoroacetic acid and elimination of water to form [Mo2 O6 (O2 CCF3 )] − and involves two steps only: (1) fluoride transfer to a molybdenum centre to form [Mo2 O6 (F)] − ; (2) reaction of [Mo2 O6 (F)] − with trifluoroacetic acid and loss of water to regenerate [Mo2 O6 (O2 CCF3 )] − . Comparisons are made with the chemistry of [Mo2 O6 (OH)] − reacting with acetic acid.