Substituent Effects and Supramolecular Interactions of Titanocene(III) Chloride: Implications for Catalysis in Single Electron Steps

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  • Andreas Gansaeuer, Univ Bonn, University of Bonn, Kekule Inst Organ Chem & Biochem, Unknown
  • Christian Kube, Univ Bonn, University of Bonn, Kekule Inst Organ Chem & Biochem, Denmark
  • Kim Daasbjerg
  • Rebecca Sure, Univ Bonn, University of Bonn, Mulliken Ctr Theoret Chem, Inst Phys & Theoret Chem, Unknown
  • Stefan Grimme, Univ Bonn, University of Bonn, Mulliken Ctr Theoret Chem, Inst Phys & Theoret Chem, Germany
  • Godfred D. Fianu, Lehigh Univ, Lehigh University, Dept Chem, Unknown
  • Dhandapani V. Sadasivam, Lehigh Univ, Lehigh University, Dept Chem, Unknown
  • Robert A. Flowers, Lehigh Univ, Lehigh University, Dept Chem, United States
The electrochemical properties of titanocene(III) complexes and their stability in THF in the presence and absence of chloride additives were studied by cyclic voltammetry (CV) and computational methods. The anodic peak potentials of the titanocenes can be decreased by as much as 0.47 V through the addition of an electron-withdrawing substituent (CO2Me or CN) to the cyclopentadienyl ring when compared with Cp2TiCl. For the first time, it is demonstrated that under the conditions of catalytic applications low-valent titanocenes can decompose by loss of the substituted ligand. The recently discovered effect of stabilizing titanocene(III) catalysts by chloride additives was analyzed by CV, kinetic, and computational studies. An unprecedented supramolecular interaction between [(C5H4R)(2)TiCl2](-) and hydrochloride cations through reversible hydrogen bonding is proposed as a mechanism for the action of the additives. This study provides the critical information required for the rational design of titanocene-catalyzed reactions in single electron steps.
Original languageEnglish
JournalJournal of the American Chemical Society
Volume136
Issue4
Pages (from-to)1663-1671
Number of pages9
ISSN0002-7863
DOIs
Publication statusPublished - 2014

    Research areas

  • TRANSFER RADICAL POLYMERIZATION, TRANSITION-METAL-COMPLEXES, HALIDE-PROMOTED REDUCTIONS, ATOM-TRANSFER, 4-EXO CYCLIZATIONS, ADDITION-REACTIONS, STRAIGHTFORWARD SYNTHESIS, EPOXYPOLYENE CYCLIZATION, HOMOLYTIC SUBSTITUTION, HOMOGENEOUS CATALYSIS

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