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Elucidating the mass spectrum of the retronecine alkaloid using DFT calculations
Author(s) -
ModestoCosta Lucas,
Martinez Sabrina T.,
Pinto Angelo C.,
Vessecchi Ricardo,
Borges Itamar
Publication year - 2018
Publication title -
journal of mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 1076-5174
DOI - 10.1002/jms.4253
Subject(s) - chemistry , mass spectrum , fragmentation (computing) , dissociation (chemistry) , molecule , density functional theory , computational chemistry , electron ionization , mass spectrometry , ion , ionization energy , ionization , stereochemistry , organic chemistry , chromatography , computer science , operating system
Pyrrolizidine alkaloids are natural molecules playing important roles in different biochemical processes in nature and in humans. In this work, the electron ionization mass spectrum of retronecine, an alkaloid molecule found in plants, was investigated computationally. Its mass spectrum can be characterized by three main fragment ions having the following m/z ratios : 111, 94, and 80. In order to rationalize the mass spectrum, minima and transition state geometries were computed using density functional theory. It was showed that the dissociation process includes an aromatization of the originally five‐membered ring of retronecine converted into a six‐membered ring compound. A fragmentation pathway mechanism involving dissociation activation barriers that are easily overcome by the initial ionization energy was found. From the computed quantum chemical geometric, atomic charges, and energetic parameters, the abundance of each ion in the mass spectrum of retronecine was discussed.