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].