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Downloaded by MICHIGAN STATE UNIV on February 18, 2015 | http://pubs.acs.org Publication Date: May 5, 1993 | doi: 10.1021/ba-1993-0238.ch008
Photoredox Chemistry of d Bimetallic Systems Colleen M. Partigianoni, Claudia Turró, Carolyn Hsu, I-Jy Chang, and Daniel G. Nocera* Department of Chemistry, Michigan State University, East Lansing, MI 48824 Excited states of quadruply bonded metal—metal complexes exhibit a rich oxidation—reduction chemistry with organic substrates. Irradiation of the Mo (II,II) diarylphosphate, Mo [O P(OC6H5)2]4, in the presence of dihalocarbons yields olefin and the one-electron oxidized mixed-valence complex, Mo [O P(OC6H5)2]4+. Photodehalogenation proceeds from the (δδ*) excited state; the primary photoevent involves the one-electron reduction of substrate. Discrete two-electron reduction of alkyl halides is observed when the photoreagent is W Cl (dppm) (dppm is diphenylphosphinomethane). The ability of the photo generated intermediates and products to assume a bioctahedral geometry is an important factor in determining the two-electron photochemistry of this complex. The photoreactivity of W Cl (dppm) provides an excited-state complement to the oxidative -additionchemistry of Vaska's complex. 2
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B l N U C L E A R METAL COMPLEXES continue to assume a prominent role in the light-initiated activation of organic substrates. The capacity of a bimetallic core to coordinate organic molecules at multiple metal sites, which feature complementary redox function upon light excitation, pro vides the opportunity to photochemically promote the multielectron activation of a variety of substrates. The most popular and successful approaches to the photochemical activation of organic substrates by binuclear complexes have been predicated on the chemistry of d - d and 7
•Corresponding author 0065-2393/93/0238-0147S06.00/0 © 1993 American Chemical Society
American Chemical Society Library 115516th
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In PhotosensitiveWashington, Metal—OrganicO.C. Systems; Kutal, C., et al.; 200» Advances in Chemistry; American Chemical Society: Washington, DC, 1993.
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PHOTOSENSITIVE M E T A L - O R G A N I C SYSTEMS
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