JESSE C. MARCUM, J. MATHIAS WEBER, JILA, NIST, and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309.
Iridium complex anions (IrBr62-, IrBr5- and IrBr4-) were studied using photodissociation spectroscopy in the photon energy range between 1.1 and 5.6 eV. These spectra probe the electronic structure of iridium bromide complexes as a function of the coordination number and metal oxidation state. The observed spectra for isolated IrBr62- contain similar features to its spectrum in aqueous solution. An analysis of the fragment channels reveals a tendency for formation of IrBr5- fragment ions in the visible while formation of IrBr4- fragment ions is favored in the ultraviolet. Spectra for IrBr5- and IrBr4- parent ions indicate that their preferred fragment channel is the loss of one or more neutral bromine atoms.