Dimeric Rare-Earth BINOLate Complexes: Activation of 1,4-Benzoquinone through Lewis Acid Promoted Potential Shifts

Authors

  • Jerome R. Robinson,

    1. Department of Chemistry, University of Pennsylvania, 231 S. 34th St. Philadelphia, PA 19104 (USA), Fax: (+215) 573-2112, Tel: (+215) 898-8633, Tel: (+215) 573-2875
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  • Corwin H. Booth,

    1. 1 Cyclotron Rd. MS70 A-1150, Chemical Sciences Division, Lawrence Berkeley National Laboratory Berkeley, CA 94720 (USA), Fax: (+510) 486-5596, Tel: (+510) 486-6079
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  • Patrick J. Carroll,

    1. Department of Chemistry, University of Pennsylvania, 231 S. 34th St. Philadelphia, PA 19104 (USA), Fax: (+215) 573-2112, Tel: (+215) 898-8633, Tel: (+215) 573-2875
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  • Patrick J. Walsh,

    Corresponding author
    1. Department of Chemistry, University of Pennsylvania, 231 S. 34th St. Philadelphia, PA 19104 (USA), Fax: (+215) 573-2112, Tel: (+215) 898-8633, Tel: (+215) 573-2875
    • Department of Chemistry, University of Pennsylvania, 231 S. 34th St. Philadelphia, PA 19104 (USA), Fax: (+215) 573-2112, Tel: (+215) 898-8633, Tel: (+215) 573-2875
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  • Eric J. Schelter

    Corresponding author
    1. Department of Chemistry, University of Pennsylvania, 231 S. 34th St. Philadelphia, PA 19104 (USA), Fax: (+215) 573-2112, Tel: (+215) 898-8633, Tel: (+215) 573-2875
    • Department of Chemistry, University of Pennsylvania, 231 S. 34th St. Philadelphia, PA 19104 (USA), Fax: (+215) 573-2112, Tel: (+215) 898-8633, Tel: (+215) 573-2875
    Search for more papers by this author

Abstract

Reaction of p-benzoquinone (BQ) with a series of rare-earth metal/alkali metal/1,1′-BINOLate (REMB) complexes (RE: La, Ce, Pr, Nd; M: Li) results in the largest recorded shift in reduction potential observed for BQ upon complexation. In the case of cerium, the formation of a 2:1 Ce/BQ complex shifts the two-electron reduction of BQ by greater than or equal to 1.6 V to a more favorable potential. Reactivity investigations were extended to other REIII (RE=La, Pr, Nd) complexes where the resulting highly electron-deficient quinone ligands afforded isolation of the first lanthanide quinhydrone-type charge-transfer complexes. The large reduction-potential shift associated with the formation of 2:1 Ce/BQ complexes illustrate the potential of Ce complexes to function both as a Lewis acid and an electron source in redox chemistry and organic-substrate activation.

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