Stereochemical effect in mass spectrometry of transition metal π-complexes

Abstract

Some aspects of monomolecular dissociation of ions of transition metal π-complexes are discussed. Fragmentation of these species is characterized by higher regio- and stereoselectivity in comparison with aromatics, cyclo-olefines and other organic ions. Such behaviour is caused by the preferable charge localization on the central metal atom. The main fragmentation pathways are determined by the direct interaction of electronegative, unsaturated substituents, and groups with a lone electron pair in π-ligands with the metal atom. Bond dissociation reactions in π-ligands are usually limited by α- and β-cleavages. Other processes are rarely observed owing to steric hindrances for interaction with the metal atom. Many reactions include the migration of the substituent or its part to the metallic centre and proceed by the «rebound» mechanism