Spectroscopy and photochemistry of metal-oxo complexes

Citation

Winkler, Jay Richmond (1984) Spectroscopy and photochemistry of metal-oxo complexes. Dissertation (Ph.D.), California Institute of Technology. http://resolver.caltech.edu/CaltechETD:etd-02272006-082939

Abstract

NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document. Electronic spectroscopic, photophysical, and photochemical investigations of two types of metal-oxo complexes are described. The electronic absorption spectra of various molybdenyl ions [...] were measured in crystals and solutions. These spectra clearly support [...] and [...] assignments for the two weak bands near 25,000 and 14,000 cm(-1), respectively, in these molecules. A Franck-Condon analysis of the [...] band in the 5K single crystal absorption spectrum of [...] indicated a [...] elongation of the metal-chloride bond in the excited state. Crystalline [...] luminesces from the lower energy component of a split [...] state with a lifetime of 160 ns at 300K, increasing to [...] at 5K. No luminescence was detected from any molybdenyl ion in solution. The electronic absorption and emission spectra of [...] were also measured in crystals and solutions. The lowest energy absorption bands are assigned to components of a split [...] state (ground state [...]). Emission from at least two of these components was identified in the cyanide and pyridine complexes and only the ethylenediamine complex failed to luminesce. Franck-Condon analyses of the emission spectra indicated ca. 0.1 A elongations of each Re-O bond in the [...] excited states. The lifetime of the [...] state varies from 10 to [...] in crystals and is ca. [...] for [...] species in aprotic solvents. Protons efficiently quench the luminescence of these molecules. Experiments directed toward photoinduced oxygen atom transfer chemistry are also described.

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