Mass Spectrometric Method for the Rapid Characterization of Transition Metal Carbonyl Cluster Reaction Mixtures

Energy-dependent electrospray ionization mass spectrometry (EDESI-MS) has been applied to the characterization of reaction products that contain a mixture of metal carbonyl cluster anions. The technique allows rapid identification of the components and provides molecular weight (parent ion), ion composition (isotope pattern), and structural information (fragmentation pattern). The spectra are presented as a two-dimensional map of cone voltage versus mass-to-charge ratio which resolves each component of the reaction product. The EDESI-MS technique is illustrated using the reaction products obtained from the reaction of [Ru6C(CO)17] and [PPN][M(CO)4] where M = Co or Ir. The anions identified from these reactions are [Ru5CoC(CO)16]-, [Ru3Co(CO)13]-, [RuCo3(CO)12]-, [HRu4Co2C(CO)15]-, [Ru5IrC(CO)16]-, [Ru3Ir(CO)13]-, and [RuIr3(CO)12]-. All the compounds have been fully characterized as their [PPN]+ salts by EDESI-MS together with other methods including single-crystal X-ray diffraction for [PPN][Ru5CoC(CO)16].