title: Gas phase reactions of 1,3,5-triazine: proton transfer, hydride transfer, and anionic σ-adduct formation.
abstract: The gas phase reactivity of 1,3,5-triazine with several oxyanions and carbanions, as well as amide, was evaluated using a flowing afterglow-selected ion flow tube mass spectrometer. Isotopic labeling, H/D exchange, and collision induced dissociation experiments were conducted to facilitate the interpretation of structures and fragmentation processes. A multi-step (→ HCN + HC(2)N                            (2)                                      (-)                          → CN(-) + 2 HCN) and/or single-step (→ CN(-) + 2 HCN) ring-opening collision-induced fragmentation process appears to exist for 1,3,5-triazinide. In addition to proton and hydride transfer reactions, the data indicate a competitive nucleophilic aromatic addition pathway (S(N)Ar) over a wide range of relative gas phase acidities to form strong anionic σ-adducts (Meisenheimer complexes). The significant hydride acceptor properties and stability of the anionic σ-adducts are rationalized by extremely electrophilic carbon centers and symmetric charge delocalization at the electron-withdrawing nitrogen positions. The types of anion-arene binding motifs and their influence on reaction pathways are discussed.
authors.affiliation: Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309, USA.
authors.forename: John M
authors.initials: JM
authors.lastname: Garver
authors.forename: Zhibo
authors.initials: Z
authors.lastname: Yang
authors.forename: Shuji
authors.initials: S
authors.lastname: Kato
authors.forename: Scott W
authors.initials: SW
authors.lastname: Wren
authors.forename: Kristen M
authors.initials: KM
authors.lastname: Vogelhuber
authors.forename: W Carl
authors.initials: WC
authors.lastname: Lineberger
authors.forename: Veronica M
authors.initials: VM
authors.lastname: Bierbaum
mesh_terms: D000838:Anions / Q000737:chemistry*; D041961:Deuterium Exchange Measurement; D005740:Gases / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry*; D013058:Mass Spectrometry / Q000379:methods*; D011522:Protons; D014227:Triazines / Q000737:chemistry*
chemical_list: D000838:Anions; D005740:Gases; D011522:Protons; D014227:Triazines; D006859:Hydrogen