PHOTOCHEMISTRY OF AZIDOPENTACARBONYLTUNGSTATE(0)

Three photoreactions are observed when the lowest energy excited state (436 nm) of the W(CO)5N3- anion is irradiated. For the PPN salt, coordinated nitrene formation leads to the production of W(CO)5NCO- in the presence of added CO (φ=0.06). For the AsPh4 salt, a complex series of secondary thermal reactions leads to a noncarbonyl product (φ=0.07). The stereochemistry of the CO substitution is investigated with labeling experiments. The photoactive excited state is assigned to an admixture of both azide to metal charge transfer and ligand field character on the basis of electronic, magnetic circular dichroism, vibrational, and emission spectra. The photochemistry is interpreted in terms of the charge transfer and ligand field character of this state, and a model of the excited-state potential surface is proposed. © 1979, American Chemical Society. All rights reserved.