Article ID Journal Published Year Pages File Type
5134231 International Journal of Mass Spectrometry 2017 7 Pages PDF
Abstract

•Anionic complexes of 1,3,5-trinitrobenzene are characterized in the gas phase.•IRMPD spectroscopy points to a covalent Meisenheimer complex structure.•Quantum chemical calculations are employed to assign experimental vibrations.•Carbon versus oxygen attack by enolate anions is discussed.

Anionic adducts of 1,3,5-trinitrobenzene (TNB) with deprotonated pyrrolidine (Pyr), imidazole (Im), acetone (Ac) and acetylacetone (Acac) have been delivered into the gas phase by electrospray ionization. The so-formed ions, TNB-Nu− (Nu = Pyr, Im, Ac, Acac), have been interrogated by IRMPD spectroscopy in the fingerprint range. DFT calculations at B3LYP/6-311++G(d,p) level have been performed for a survey of candidate structures. All adducts conform to anionic σ-complexes (Meisenheimer complexes). The symmetric stretching modes of the nitro groups yield a dominant vibrational signature at 1200-1250 cm−1, the red-shift with respect to the degenerate frequency of 1367 cm−1 in neutral TNB reflecting the extent of negative charge delocalization. The enol complexes TNB-Ac− and TNB-Acac− are largely represented by C-bonded species.

Graphical abstractDownload high-res image (235KB)Download full-size image

Related Topics
Physical Sciences and Engineering Chemistry Analytical Chemistry
Authors
, , ,