Generation of Alkoxide Anions from a Series of Aliphatic Diols and Alcohols and Their Ion—Molecule Reactions with Carbon Dioxide in the Gas Phase

Abstract

Alkoxide anions, [M – H]⁻ from a series of aliphatic diols and alcohols are generated in the source under negative ion electrospray ionisation conditions by cone-voltage fragmentation of the corresponding [M + F]⁻ ions. The collision-induced dissociation (CID) spectra of [M – H]⁻ ions consist of [M – H – 2H]⁻ ions, in addition to the other characteristic fragment ions, and the relative abundance of [M – H – 2H]⁻ ions among the series of diols varies as a function of chain length that could be explained based on their stabilities through intramolecular hydrogen bonding. The reactivity of alkoxide anions is studied through ion–molecule reactions with CO₂ in the collision cell of a triple quadrupole mass spectrometer. All the alkoxide anions reacted with CO₂ and formed corresponding carbonate anions, [M – H + CO₂]⁻ ions. The reactivity of alkoxide anions within the series of diols also reflected the stability of their [M – H]⁻ ions.