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Research on Chemical Intermediates

, Volume 20, Issue 9, pp 939–951 | Cite as

Reduction of triplet tetraphenyl-prophyrin dication by aryl amines and hydroquinones: Kinetics and primary radical yields

  • Biczók LÁszló 
  • Henry Linschitz 
  • Robert I. Walter 
Article

Abstract

The photophysics and one-electron reduction of triplet tetraphenylporphyrin dication by homologous series of substituted triphenylamines and hydroquinones in acetone solution have been studied by nanosecond flash photolysis. Triplet yield is 0.3 and direct internal conversion from the singlet is a major decay pathway. Quenching rates (109 - 106 M-1; s-1) for reductants covering a range of ΔG0 0.4 V lead to reorganization energies λ 0.6 ±0.1 eV. Radical yields (0.38 for the amines) are remarkably constant for recombination free energies between 1.02 and 1.45 V. A rate-limiting step in the back reaction is suggested, involving spin-orbit relaxation of the primary radical pair.

Keywords

Porphyrin Hydroquinone Aryl Amine Reorganization Energy Triphenylamines 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer 1994

Authors and Affiliations

  • Biczók LÁszló 
    • 1
  • Henry Linschitz 
    • 1
  • Robert I. Walter 
    • 2
  1. 1.Department of ChemistryBrandeis UniversityWalthamUSA
  2. 2.Department of ChemistryUniversity of Illinois at ChicagoChicagoUSA

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