FAST-ATOM-BOMBARDMENT TANDEM MASS-SPECTROMETRY OF (POLYPYRIDYL)RUTHENIUM(II) COMPLEXES

The mass spectra of some (polypyridyl)ruthenium(II) complexes of the type [Ru(x)L(bpy)2x](PF6)2x (L = 2,2':6,2" -terpyridine (x = 1), 3,3':5,3" -bis(dimethylene)-2,2':6,2" -terpyridine (x = 1), 5,6,9,10,11,12,15,16-octahydrocycloocta[1",2":5,6;4",3":5',6'] dipyrido[2,3-b:2',3'-b]di[1,10]phenanthroline (x = 1,2), and N,N'-dimethylene-2,2'-biimidazole (x = 1; bpy = 2,2'-bipyridine) have been investigated by using fast atom bombardment tandem mass spectrometry. The low-energy collision-induced dissociation (CID) spectra provide confirmation of the structures and details about fragmentations of the complexes. The observed decomposition pathways involve losses of intact ligands, PF6- counterions, simple bond cleavages, fluoride transfers from the PF6- counterion to the Ru(II) center with loss of PF5, and reductive eliminations of HF. The fluoride-transfer reaction can be used to determine the coordination of the chelating ligands in the parent complex.