Electrospray ionization of neutral metal dithiocarbamate complexes using in-source oxidation

Area of Science:

• Analytical Chemistry
• Mass Spectrometry
• Coordination Chemistry

Background:

• Dithiocarbamate complexes of various transition metals are of interest due to their diverse applications.
• Characterization of these complexes using mass spectrometry can provide valuable structural and chemical information.
• Electrospray ionization (ESI) is a powerful technique for analyzing non-volatile and thermally labile compounds.

Purpose of the Study:

• To characterize eight substituted tris(dithiocarbamato)iron(III) complexes and related complexes of Mn(III), Cu(II), Ni(II), and Co(III) using ESI mass spectrometry.
• To investigate the utility of in-source oxidation and collision-induced dissociation (CID) for analyzing these metal complexes.
• To compare in-source oxidation results with previous studies using external oxidizing agents.

Main Methods:

• Electrospray ionization (ESI) mass spectrometry was employed for the analysis.
• In-source oxidation, utilizing the electrochemical potential of the ESI source, was performed.
• In-source collision-induced dissociation (CID) was used to fragment ions and gain structural insights.

Main Results:

• ESI mass spectra showed molecular ions of oxidized complexes and fragment ions resulting from ligand loss.
• Fragmentation of dithiocarbamate ligands was observed for some iron(III) complexes.
• Ions corresponding to thiuram disulfide, formed from excess dithiocarbamate oxidation, were detected.
• In-source CID of various metal complexes yielded protonated ions attributed to proton transfer mechanisms.

Conclusions:

• In-source oxidation and CID are effective methods for characterizing metal dithiocarbamate complexes without external reagents.
• The study provides detailed mass spectral data for several metal dithiocarbamate complexes.
• The findings contribute to the understanding of the behavior of these complexes under ESI-MS conditions.