title: Differentiation of diastereoisomers of protected 1,2-diaminoalkylphosphonic acids by EI mass spectrometry and density functional theory.
abstract: Electron ionization mass spectrometry and density functional theory (DFT) calculations have been used to study the fragmentation of diastereoisomers of protected 1,2-diaminoalkylphosphonic acids. The loss of a diethoxyphosphoryl group and the elimination of diethyl phosphonate were found to be competitive fragmentation processes, which can be used to differentiate both stereoisomers. Selective deuterated analogs and product- and precursor-ion mass spectra allowed the elucidation of the fragmentation mechanisms. The structures of the transition states and product ions were optimized using the density functional theory (DFT), and free energy calculations confirmed the observed differences in the formation and relative intensities of specific fragment ions.
authors: Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Laboratory for Analysis of Organic Compounds and Polymers, Łódź, Poland. ewdrabik@wp.pl
authors: Ewelina
authors: E
authors: Drabik
authors: Grzegorz
authors: G
authors: Krasiński
authors: Marek
authors: M
authors: Cypryk
authors: Roman
authors: R
authors: Błaszczyk
authors: Tadeusz
authors: T
authors: Gajda
authors: Marek
authors: M
authors: Sochacki
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