Identification and Structural Assessment of Alkaline-Earth Metal Complexes with Flavonols by FAB Mass Spectrometry

摘要

Complexation of a series of flavonols with Mg~(2+),Ca~(2+),and Ba~(2+) ions was studied by FAB mass spectrometry.The mass spectra of flavonol solutions containing magnesium ions revealed formation of 1:2 complexes MgL_2,undetectable by spectrophotometric and spectrofluorimetric methods.Experiments with a crown-substituted flavonol revealed formation of not unly previously known chelate complexes MgL and Mg_2L,but also of the 1:2 complex MgL_9 and crown complex MgHL.The barium ions form with the crown-substituted flavonol two types of "sandwich" complexes:Ba(HL)_2 and Ba_2(HL)_2.With the Ca~(2+) ions,such complexes are not formed,and only the fragmentation product of the complex Ca(HL)_2 was detected.