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Spectroscopy and Photochemistry of Metal-Oxo Complexes


Winkler, Jay Richmond (1984) Spectroscopy and Photochemistry of Metal-Oxo Complexes. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/DE5E-2Y69.


Electronic spectroscopic, photophysical, and photochemical investigations of two types of metal-oxo complexes are described. The electronic absorption spectra of various molybdenyl ions (MoO3+ were measured in crystals and solutions. These spectra clearly support 2B1(x2-y2) ← 2B2(xy) and 2E(xz, yz) ← 2B2(xy) assignments for the two weak bands near 25,000 and 14,000 cm-1, respectively, in these molecules. A Franck-Condon analysis of the 2B12B2 band in the 5 K single crystal absorption spectrum of (Ph4As)MoOCl4 indicated a 0.07(1) Å elongation of the metal-chloride bond in the excited state. Crystalline (Ph4As)MoOCl4 luminesces from the lower energy component of a split 2E(xz, yz) state with a lifetime of 160 ns at 300 K, increasing to 1.4 µs at 5 K. No luminescence was detected from any molybdenyl ion in solution.

The electronic absorption and emission spectra of trans-ReO2L4z (L = CN-, z = 3-; L = 1/2(ethylenediamine), z = +; L = pyridine, z = +; L = 4-picoline, z = +; L = 4-t-butylpyridine, z = +) were also measured in crystals and solutions. The lowest energy absorption bands are assigned to components of a split 3Eg[(eg)1(b2g)1] state (ground state 1Ag1g[(b2g)2]). 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 Å elongations of each Re-O bond in the 3Eg excited states. The lifetime of the 3Eg state varies from 10 to 300 µs in crystals and is ca. 10 µs for trans-ReO2L4z species in aprotic solvents. Protons efficiently quench the luminescence of these molecules. Experiments directed toward photoinduced oxygen atom transfer chemistry are also described.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:Chemistry
Degree Grantor:California Institute of Technology
Division:Chemistry and Chemical Engineering
Major Option:Chemistry
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Goddard, William A., III
Thesis Committee:
  • Goddard, William A., III (chair)
  • Gray, Harry B.
  • Anson, Fred C.
  • Collins, Terrence J.
Defense Date:16 August 1983
Funding AgencyGrant Number
Record Number:CaltechETD:etd-02272006-082939
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:781
Deposited By: Imported from ETD-db
Deposited On:03 Mar 2006
Last Modified:21 Dec 2019 04:41

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