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 occurring before ionization, likely involving the hydroxylamino group, has been observed. Compounds having a carbonyl group at position 6 of the triazine ring fragment in the source by elimination of NO followed by HF 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 the molecular ion the unpaired electron is mainly located on the exocyclic nitrogen, while the positive charge is on the C(6) carbon atom.

The ESI CAD fragmentations of protonated 2,4,6‐tris(benzylamino)‐ and tris(benzyloxy)‐1,3,5‐triazines involve benzyl–benzyl interactions: a DFT study

“…As a part of an ongoing synthetic research program toward the synthesis of s ‐triazine derivatives for structural investigation and evaluation of their biological activity, we have synthesized a new series of 2,4,6‐tri substituted s ‐triazines . The applications of electron ionization and electrospray ionization (ESI) mass spectrometry to various substituted triazines are well known in the literature . Tandem mass spectrometric experiments have shown that the dissociation of protonated molecules containing more than one benzyl groups yield product ion of m/z 181 having molecular formula C 14 H 13 + due to benzyl‐benzyl interactions .…”

“…[16] The applications of electron ionization and electrospray ionization (ESI) mass spectrometry to various substituted triazines are well known in the literature. [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36] Tandem mass spectrometric experiments have shown that the dissociation of protonated molecules containing more than one benzyl groups yield product ion of m/z 181 having molecular formula C 14 H 13 + due to benzyl-benzyl interactions. [37][38][39][40][41][42] Examples include study of the protonated dibenzyl esters of dicarboxylic acid generated by chemical ionization [40] and N,N 0 -dibenzylpiperzines produced by ESI.…”