Formation of organometallic species from complexes of N-phenylaza-crown ether conjugates with lead cations in CID-MS/MS conditions

Abstract

Gas phase decomposition of the ions [M+PbNO3]+ (M stands for fluoro-substituted N-nitrophenylaza-crown ether conjugate), has been studied by the electrospray ionization-collision induced dissociation-tandem mass spectrometry (ESI-CID-MS/MS). The conjugates containing hydrogen atom at ortho position to the crown moiety, form abundant fragment ions which can be assigned as complexes of deprotonated conjugates and lead cation, thus the ions [M−H+Pb]+ (fragment ions formed as a result of HNO3 loss). Interaction between the nitro group (present at the second ortho position to the crown moiety) and the metal cation affects the formation of fragment ion [M−H+Pb]+ (but does not prevent its formation). Ions [M−H+Pb]+ are very rare example of the organometallic species (containing metal-carbon bond), in which metal cation is also complexed by crown ether moiety.