title: Dimeric rare-earth BINOLate complexes: activation of 1,4-benzoquinone through Lewis acid promoted potential shifts.
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 RE(III) (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.
authors.affiliation: Department of Chemistry, University of Pennsylvania, 231 S. 34th St. Philadelphia, PA 19104, USA.
authors.forename: Jerome R
authors.initials: JR
authors.lastname: Robinson
authors.forename: Corwin H
authors.initials: CH
authors.lastname: Booth
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Carroll
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Walsh
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Schelter
mesh_terms: D016227:Benzoquinones / Q000737:chemistry*; D002563:Cerium / Q000737:chemistry*; D004563:Electrochemistry; D028581:Lanthanoid Series Elements / Q000737:chemistry*; D058116:Lewis Acids / Q000737:chemistry*; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D008674:Metals, Rare Earth / Q000737:chemistry*; D010084:Oxidation-Reduction
chemical_list: D016227:Benzoquinones; D028581:Lanthanoid Series Elements; D058116:Lewis Acids; D008024:Ligands; D008674:Metals, Rare Earth; D002563:Cerium