Gas-phase fluorination of acetylene by XeF+: Formation, structure and reactivity of C2H2F+ isomeric ions

The gas-phase reactivity of XeF+ towards acetylene was investigated by triple quadrupole mass spectrometry. XeF+ promotes both F+ and Xe+ transfer to acetylene, yielding C2H2F+ and C2H2Xe+, respectively. The C2H2F+ ions formed were probed by low-energy collisionally activated dissociation mass spectrometry and characterized as CH2CF+, namely the isomer identified as the most stable by previous theoretical studies. The 1-fluorovinyl cation reacts in the gas-phase with typical nucleophiles (CH3COCH3,CH3CN,CH3OH,C2H4), as a Brønsted acid and/or as a fluorinating agent, depending on the thermochemistry of the processes involved.