Electrospray ionization mass spectrometry for mechanism analysis of metal ion complexation and photoionization of Malachite Green derivatives incorporating a crown ether moiety

Electrospray-ionization mass spectrometry using a photoirradiation interfac e has been successfully applied to the investigation of metal-ion complexat ion and photoionization of crowned Malachite Green leuconitrile derivatives in solution. The mass spectrometry clearly showed that the Malachite Green derivatives in their electrically neutral forms can complex metal ions wit h their crown ether moiety. Ionization of the Malachite Green derivatives t o their corresponding cationic forms, accompanied by metal-ion repelling fr om their crown ether moiety, was detected upon W-light irradiation. A remar kably different photoionization behavior in various solvents, which is diff icult to detect by other analytical techniques, was also found by the mass spectrometry.