Unique para-effect in electron ionization mass spectra of bis(perfluoroacyl) derivatives of bifunctional aminobenzenes

Published

September 15, 2010

Author(s)

Kirill V. Tretyakov, Nino G. Todua, Roman S. Borisov, Vladimir G. Zaikin, Stephen Stein, Anzor I. Mikaia

Abstract

A new kind of "para-effect" under EI conditions has been discovered for a series of bis(perfluoroacyl) derivatives of o-, m- and p- phenylendiamines, hydroxybenzeneamines and mercaptobenzeneamines of a common structure RCOX C₆H₄ NHCOR (X = NH, S, O; R = CF₃, C₂F₅, C₃F₇). Only para-isomers showed successive loss of radical RCO and molecule RCN, leading to very intense peaks in the EI spectra. The composition and the origin of the [M - COR - NCR]⁺ ions were confirmed by exact mass measurements and linked scan experiments. The proposed mechanism of their formation takes into account likely para-quinoid structures of the precursor ions. A similar rearrangement has not been observed for para-isomers in the series of bis(perfluoroacyl) derivatives of benzenediols, mercaptophenols and dimercaptobenzenes.

Citation

Rapid Communications in Mass Spectrometry

Volume

24

Issue

17

Pub Type

Journals

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Keywords

bifunctional benzenes, bis(perfluoroacyl) derivatives, electron ionization mass spectra, para-effect

Citation

Tretyakov, K. , Todua, N. , Borisov, R. , Zaikin, V. , Stein, S. and Mikaia, A. (2010), Unique para-effect in electron ionization mass spectra of bis(perfluoroacyl) derivatives of bifunctional aminobenzenes, Rapid Communications in Mass Spectrometry, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=905023 (Accessed October 20, 2025)