Electron impact studies. CXIII. Aromatic nucleophilic substitution in the gas phase. The dinitrobenzenes. An ion cyclotron resonance study

Abstract

The negative ion mass spectra derived from the three dinitrobenzenes show NO₂^-, [M^-?-NO^?]^- and M^-? as major ions. The i.c.r. spectrum of o- dinitrobenzene shows the formation of the adducts [M+NO₂^-]^-, [M+(M^-?-NO^?)^- ]^- and 2M^-?, but the m- and p-dinitrobenzenes only produce the adduct [M+NO₂^-]^-. The nucleophile Cl^- adds to each of the three dinitrobenzene neutrals in the abundance ratio o >> m ≈ p. Evidence is presented which suggests that the neutral products formed by the reaction between NO₂^- and o-dinitrobenzene are dinitro- and trinitro-benzenes, whereas those resulting from the interaction of Cl^- with o-dinitrobenzene are chloronitrobenzene and a chloro-dinitrobenzene.