Gas‐phase reactions of electrons, halide ions and radicals with (meso‐tetraphenylporphinato)metal(II) complexes under negative ion chemical ionization conditions

Abstract

AbstractThe negative ion chemical ionization mass spectra of a series of (meso‐tetraphenylporphinato)metal(II) (metal = Mg, Co, Ni, Cu, Zn) complexes obtained with the electron‐energy‐moderating/reagent gases argon, NF3, CF2Cl2 and CF3Br are presented. Formation of the negative ions identified in the mass spectra is accounted for in terms of the chemistry which occurs in the gaseous plasmas. In argon plasmas, the metal complexes undergo resonance electron capture with comparable facility to produce stable molecular ions. In the NF3, CF2Cl2 and CF3Br plasmas, ionization occurs as a result of ion–molecule reactions as well as resonance electron capture, and is quite selective. Only fluoride ions react with each of the metal complexes, producing metal‐containing ions by nucleophilic addition and proton abstraction as well as by inducing ring closure. The less reactive chloride and bromide ions react readily by nucleophilic addition only with the magnesium and zinc complexes. Negative ions are also produced in the plasmas by radical‐molecule reactions followed by ionization of the neutral products of these encounters.