Aromatic ring destruction in complexes of dipositive metal cations

Singly charged metal cations do not normally activate the π-ring in monoaromatic ligands. Here pyridine complexes of six dipositive metal cations (Ca, Mg, Mn, Fe, Co, and Cu) are probed using collisional dissociation. Except for Cu, species with one–three ligands (depending on the metal) exhibit two significant aromaticity-destroying ligand cleavage processes. One proceeds with charge reduction yielding singly charged bare or ligated metal cyanide cations and C4H5+, and the other retains the double charge eliminating one or two small neutrals such as NH2 or CH3. The previously reported cluster-to-metal charge transfer producing charged ligand clusters is shown to not occur.