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Differential mass spectrometry (DifMS) and computational chemistry.Part I. DifMS and semiempirical MO analysis of 3- and 4- nitrobenzophenone dimethyl acetals

Domenii publicaţii > Chimie + Tipuri publicaţii > Articol în revistã ştiinţificã

Autori: N.Dinca,E.Sisu,M.Mracec,I.Opean, O.Sander

Editorial: Rev. Roum. Chim., 49(3-4), p.331-338, 2004.

Rezumat:

Comparative analysis of the electronic impact mass spectra (EI-MS) of the 3- and 4-nitrobenzophenone acetals leads to the observation that the fragmentation of these compounds is similar.The paper presents a method for the correlation of the experimentally obtained differential mass spectrum Pms with the heat of formation calculated by the semiempirical methods AM1 and PM3 for the ions generated in the mass spectrometer.These methodology allows for the localization of the position of the nitro group in the aromatic ring without using standards or spectral libraries, but only the spectra of the two compounds wich are position isomers. Also the whole methodology for the calculation of the differential mass spectra Pms is presented: collecting, correction and differentiation manner for the mass spectra of the two substances.One can conclude that the stability of the MS fragmentation cations estimated from the calculated heat of formation is in agreement with the data offered by the differential mass spectra.

Cuvinte cheie: computational chemistry, acetals, mass spectrometry