Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/102408
Type: Artigo de periódico
Title: The Kinetic Method As A Structural Diagnostic Tool: Ionized α-diketones As Loosely One-electron Bonded Diacylium Ion Dimers
Author: Meurer E.C.
Gozzo F.C.
Augusti R.
Eberlin M.N.
Abstract: The kinetic method is used to corroborate the description of ground state ionized α-diketones as loosely electron-bonded acylium ion dimers: R 1-C=O+ - e- - +O=C-R2. The abundance ratio of both the acylium ion fragments R1CO + and R2CO+ (summed to those of their respective secondary fragments) formed upon low energy (5 eV) collision-induced dissociation of several ionized α-diketones is found to correlate linearly with the ionization energies (IEs) of the corresponding R 1CO• and R2CO• free radicals as predicted by density functional theory calculations at the B3LYP/6-311++G(d,p) level. However, when these abundances are taken from 70 eV electron ionization mass spectra, lower and sometimes inverted ratios (2,3-pentanedione and 2,3-hexanedione) are observed. Inverted ratios are also observed via charge-exchange mass spectrometry/mass spectrometry (MS/MS) experiments for ionized 2,3-pentanodione formed with relatively high internal energies. Ionized α-diketones are found to display an effective temperature of 1705 K, which indicates an intermediate loosely-bonded nature. B3LYP/6-311++G(d,p) optimized geometries and charge and spin densities also corroborate the description of ground state ionized α-diketones as loosely electron-bonded diacylium ion dimers.
Editor: 
Rights: fechado
Identifier DOI: 10.1255/ejms.563
Address: http://www.scopus.com/inward/record.url?eid=2-s2.0-0141784858&partnerID=40&md5=c3c5b24ae0bf5cd083f6f88210e3fe32
Date Issue: 2003
Appears in Collections:Unicamp - Artigos e Outros Documentos

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