Gas phase behavior of radical cations of perfluoroalkyl-1,2,4-triazines: an experimental and theoretical study

Abstract

Electron ionization mass spectrometry and low-energy collision-induced decomposition reactions occurring in a tridimensional ion trap, together with density functional theory (DFT) calculations on neutrals, even- and odd-electron cations, have been used to study the gas-phase ion chemistry of a series of perfluoroalkyl-1,2,4-triazines. Loss of oxygen, due to thermal degradation occurringbefore ionization, likely involving the hydroxylaminogroup, hasbeen observed.Compounds having a carbonyl group at position 6 of the triazine ring fragment in the source by elimination ofNOfollowed byHF or CO. The decomposition pathways occurring due to CID experiments have shown interesting features depending on the nature and structure of precursor ions. Most of them involve elimination of endocyclic atoms, thereby producing contraction of the original six-membered ring or formation of acyclic structures. DFT (B3LYP/6-31G(d,p)) calculations have been used for evaluating structure, stability and properties of neutral and ionic species involved in gas-phase processes. In particular, it has been calculated that in themolecular ion the unpaired electron is mainly located on the exocyclic nitrogen, while the positive charge is on the C(6) carbon atom.