Mass Spectrometry

Biological systems have difficulties to differentiate between Fe3+ and Ga3+ ions due to their nearly identical ionic radii, same charge, preferred coordination number and chemical behavior. However, Ga3+ lacks the redox activity of iron (3+/2+ redox chemistry) and is marked as “Trojan Horse” in biological systems. Aroylhydrazones can act as neutral, monoanionic or dianionic ONO tridentate ligands. In this lecture the coordination abilities of aromatic hydrazones derived from nicotinic acid hydrazide and differently substituted 2-hydroxybenzaldehydes towards Fe3+ and Ga3+ will be discussed. Stability constants and the stoichiometry of the corresponding M3+: hydrazone complexes in MeOH/H2O media were determined spectrophotometrically. Mass spectrometry was used for structural characterization of the complexes in solution. The MS/MS spectra and fragmentation pathways of ligands and the complexes will be presented.