Macrocyclic ligands examined by fast atom bombardment mass spectrometry: direct observation of metal cation selectivity in complexation

Abstract

Complex formation between metal cations and macrocyclic ligands has been observed by fast atom bombardment (F.A.B) mass spectrometry of their aqueous glycerol and other solutions, the abundances of gas-phase ions at m/z values corresponding to metal cation–ligand complexes reflecting closely the calculated concentrations of these complexes in solution at normal temperatures; the results suggest that metal cation–ligand complex formation in solution for wide ranges of metal cations and many different types of macrocyclic ligands can be assessed rapidly and semi-quantitatively by the F.A.B. technique.