ANALYSIS OF MULTIPLY-CHARGED OXO-BRIDGED COMPLEXES BY ELECTROSPRAY-IONIZATION MASS-SPECTROMETRY

Twenty-one multiply charged oxobridged complexes with mu(2)-oxo and/or mu(2)-O,,O'-oxoacid bridges, have been characterized by electrospray ionization mass spectrometry (ESMS). No fragmentation was observed and in most cases the base peak could be assigned to the intact cationic complex (two to four charges). In a few cases the mass spectra indicat ed the lability in solution of these particular complexes. Other promi nent peaks could be assigned to adducts between the cationic complex a nd the counter ion. The spectra supply clear-cut evidence for the nucl earity of all the complexes and, in general, enabled an unambiguous de termination of the oxidation state of the metal centers and the compos ition of the bridges.