Gas‐phase dissociation of 1,4‐naphthoquinone derivative anions by electrospray ionization tandem mass spectrometry |
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| Authors: | Ricardo Vessecchi Carlos A Carollo José N C Lopes Antonio E M Crotti Norberto P Lopes Sérgio E Galembeck |
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| Institution: | 1. Departamento de Química, Faculdade de Filosofia Ciências e Letras de Ribeir?o, Preto, Universidade de S?o Paulo, Ribeir?o Preto, SP, Brazil;2. Departamento de Física e Química, Faculdade de Ciências Farmacêuticas de Ribeir?o Preto, Universidade de S?o Paulo, Ribeir?o Preto, SP, Brazil;3. Núcleo de Pesquisas em Ciências Exatas, Universidade de Franca, Franca, SP, Brazil |
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| Abstract: | Gas‐phase dissociation pathways of deprotonated 1,4‐naphthoquinone (NQ) derivatives have been investigated by electrospray ionization tandem mass spectrometry (ESI‐MS/MS). The major decomposition routes have been elucidated on the basis of quantum chemical calculations at the B3LYP/6‐31 + G(d,p) level. Deprotonation sites have been indicated by analysis of natural charges and gas‐phase acidity. NQ anions underwent an interesting reaction under collision‐induced dissociation conditions, which resulted in the radical elimination of the lateral chain, in contrast with the even‐electron rule. Possible pathways have been suggested, and their mechanisms have been elucidated on the basis of Gibbs energy and enthalpy values for the anions previously described at each pathway. Copyright © 2009 John Wiley & Sons, Ltd. |
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| Keywords: | fragmentation theoretical calculations quinone gas‐phase acidity |
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