Skip to main content
SpringerLink
Log in

Photosynthetic Model Systems That Address the Role of Superexchange in Electron Transfer Reactions

  • Conference paper
Perspectives in Photosynthesis

Part of the book series: The Jerusalem Symposia on Quantum Chemistry and Biochemistry ((JSQC,volume 22))

  • 94 Accesses

Abstract

Four fixed-distance porphyrin-quinone molecules, 1–syn, 1–anti, 2–syn, and 2–anti, were synthesized. These molecules possess a zinc 5–phenyl-10,15,20–tripentylporphyrin electron donor attached to a naphthoquinone via a rigid pentiptycene spacer. The central benzene ring of the spacer is unsubstituted in 1 and possesses p-dimethoxy substituents in 2. The naphthoquinone is oriented either syn or anti to the porphyrin across the spacer. These molecules provide information concerning the orientation dependence of electron transfer between the porphyrin and the quinone, and the dependence of this transfer on low-lying ionic states of the spacer. The rate constants for the oxidation of the porphyrin lowest excited singlet state by the naphthoquinone are 1–syn: 8.2 × 109 s-1; 1–anti: 1.7 × 1010 s-1; 2–syn: 8.5 × 109 s-1; 2–anti: 1.9 × 1010 s-1. The corresponding rate constants for the porphyrin cation — naphthoquinone anion recombination reaction are 1–syn: 1.4 × 1010 s-1; 1–anti: 2.5 × 1010 s-1; 2–syn: 5.0 × 1010 s-1; 2–anti: 8.2 × 1010 s-1. The rate constants for the syn isomers are uniformly a factor of about 2 slower than those of the anti isomers. The charge separation reaction rates for 1 and 2 are similar, while the ion pair recombination reactions are about 3–4 × faster in 2 than in 1. The conformational effect is attributed to better overlap of the spacer wave functions in the anti vs the syn conformation, while the increase in recombination rate for 2 over 1 is attributed to a superexchange interaction involving an electronic configuration of the spacer in which the dimethoxybenzene cation contributes.

This is a preview of subscription content, log in via an institution to check access.

Access this chapter

Log in via an institution
Chapter
USD 29.95
Price excludes VAT (USA)
  • Available as PDF
  • Read on any device
  • Instant download
  • Own it forever
eBook
USD 39.99
Price excludes VAT (USA)
  • Available as PDF
  • Read on any device
  • Instant download
  • Own it forever
Softcover Book
USD 54.99
Price excludes VAT (USA)
  • Compact, lightweight edition
  • Dispatched in 3 to 5 business days
  • Free shipping worldwide - see info

Tax calculation will be finalised at checkout

Purchases are for personal use only

Institutional subscriptions

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Deisenhofen J., Epp, O., Miki, K., Huber, R., and Michel, H. (1984) ‘X-ray structure analysis of a membrane protein complex. Electron density map at 3 Å resolution and a model of the chromophores of the photosynthetic reaction center from Rhodopseudomonas viridis’, J. Mol. Biol., 180, 385–398.

    Article  Google Scholar 

  2. Larsson, S. (1981) ‘Electron transfer in chemical and biological systems. Orbital rules for nonadiabatic transfer’, J. Am. Chem. Soc., 103, 4034–4040.

    Article  CAS  Google Scholar 

  3. Larsson, S. (1983) ‘Electron transfer in proteins’, J. Chem. Soc., Faraday Trans. 2, 79, 1375–1388.

    Google Scholar 

  4. Miller, J. R., Beitz, J. V., and Huddleston, R. K. (1984) ‘Effect of free energy on rates of electron transfer between molecules’, J. Am. Chem. Soc, 106. 5057–5068.

    Article  CAS  Google Scholar 

  5. Wasielewski, M. R. (1988) ‘Distance dependencies of electron transfer reactions’, in M. A. Fox and M. Chanon (eds.), Photoinduced Electron Transfer, Part A, Elsevier, Amsterdam, pp. 161–206.

    Google Scholar 

  6. Wasielewski, M. R., Niemczyk, M. P., Svec, W. A., and Pewitt, E. B. (1985) ‘Dependence of rate constants for photoinduced charge separation and dark charge recombination on the free energy of reaction in restricted distance porphyrin-quinone molecules’, J. Am. Chem. Soc, 107, 1080–1082.

    Article  CAS  Google Scholar 

  7. Wasielewski, M. R. and Niemczyk, M. P. (1986) ‘Distance-dependent rates of photoinduced charge separation and dark charge recombination in fixed-distance porphyrin-quinone molecules’ in M. Gouterman, P. M. Rentzepis and K. D. Straub (eds.), Porphyrins — Excited States and Dynamics, ACS Symposium Series No. 321, American Chemical Society, Washington, D.C., pp. 154–165.

    Chapter  Google Scholar 

  8. Joran, A. R., Leland, B. A., Geller, G. G., Hopfield, J. J., and Dervan, P. B. (1984) ‘Models for photochemical electron transfer at fixed distances. Porphyrinbicyclo(2.2.2.)octane-quinone and porphyrin-bibicyclo(2.2.2.)octane-quinone’, J. Am. Chem. Soc, 106, 6090–6092.

    Article  CAS  Google Scholar 

  9. Schmidt, J. A., Siemiarczuk, A., Weedon, A. C., and Bolton, J. R. (1985) ‘Intramolecular photochemical electron transfer 3. Solvent dependence of fluorescence quenching and electron transfer rates in a porphyrin-amide-quinone molecule’, J. Am. Chem. Soc, 107. 6112–6114.

    Article  CAS  Google Scholar 

  10. Marcus, R. A. (1988) ‘Superexchange versus an intermediate BChl- mechanism in reaction centers of photosynthetic bacteria’, Chem. Phys. Lett., 133. 471–477.

    Article  Google Scholar 

  11. Won, Y. and Friesner, R. A. (1988) ‘On the viability of the superexchange mechanism in the primary charge separation of bacterial photosynthesis’, Biochim. Biophys. Acta, 935. 9–18.

    Article  CAS  Google Scholar 

  12. Bixon, M., Jortner, J., Plato, M., and Michel-Beyerle, M. E. (1988) ‘Mechanism of the primary charge separation in bacterial photosynthetic reaction centers’, in The Bacterial Reaction Center, Structure and Dynamics, J. Breton and A. Vermeglio, (eds.) Plenum, New York, pp. 399–419.

    Google Scholar 

  13. McConnell, H. M. (1961) ‘Intramolecular charge transfer in aromatic free radicals’, J. Chem. Phys., 35, 508–515.

    Article  CAS  Google Scholar 

  14. Paddon-Row, M. N. (1982) ‘Some aspects of orbital interactions through bonds: Physical and chemical consequences’, Acc. Chem. Res., 15, 245–251.

    Article  CAS  Google Scholar 

  15. Ohta, K., Closs, G. L., Morokuma, K., and Green, N. J. (1986) ‘Stereoelectronic effects in intramolecular long-distance electron transfer in radical anions as predicted by ab initio MO calculations’, J. Am. Chem. Soc., 108, 1319–1320.

    Article  CAS  Google Scholar 

  16. Beratan, D. N. and Hopfield, J. J. (1984) ‘Calculation of electron tunneling matrix elements in rigid systems. Mixed-valence dithiaspirocyclobutane molecules’, J. Am. Chem. Soc, 106, 1584–1594.

    Article  CAS  Google Scholar 

  17. Larsson, S. and Volosov, A. J. (1986) ‘Distance dependence in photo-induced intramolecular electron transfer’, J. Chem. Phys., 85, 2548–2554.

    Article  CAS  Google Scholar 

  18. Redi, M and Hopfield, J. J. (1988) ‘Theory of thermal and photoassisted electron tunneling’, J. Chem. Phys., 72, 6651–6660.

    Article  Google Scholar 

  19. Marcus, R. A. (1988) ‘An internal consistency test and its implications for the initial steps in bacterial photosynthesis’, Chem. Phys. Lett., 146. 13–22.

    Article  CAS  Google Scholar 

  20. Joachim, C. (1987) ‘Ligand-length dependence of the intramolecular electron transfer through-bond coupling parameter’, Chem. Phys., 116, 339–349.

    Article  CAS  Google Scholar 

  21. Heitele, H. and Michel-Beyerle, M. E. (1985) ‘Electron transfer through aromatic spacers in bridged electron donor-acceptor molecules’, J. Am. Chem. Soc, 107. 8286–8288.

    Article  CAS  Google Scholar 

  22. Heitele, H. and Michel-Beyerle, M. E. (1985) ‘Electron transfer through aromatic spacers in bridged electron donor-acceptor molecules’, in M. E. Michel-Beyerle, (ed.), ‘Antennas and Reaction Centers of Photosynthetic Bacteria’, Springer, Berlin, pp. 250–255.

    Google Scholar 

  23. Hart, H., Bashir-Hashemi, A., Luo, J., and Meador, M. A. (1986) ‘Iptycenes. Extended triptycenes’, Tetrahedron, 42, 1641–1654.

    Article  CAS  Google Scholar 

  24. Wasielewski, M. R., Johnson, D. G., Svec, W. A., Kersey, K. M., and Minsek, D. W. (1988) ‘Achieving high quantum yield charge separation in porphyrin-containing donor-acceptor molecules at 10 K’, J. Am. Chem. Soc, 110, 7219–7221.

    Article  CAS  Google Scholar 

  25. Howell, J. O., Goncalves, J. M., Amatore, C, Klasinc, L., Wightman, R. M., and Kochi, J. A. (1984) ‘Electron transfer from aromatic hydrocarbons and their π complexes with metals. Comparison of the standard oxidation potentials and vertical ionization potentials’, J. Am. Chem. Soc, 106, 3968–3976.

    Article  CAS  Google Scholar 

  26. Mortensen, J. and Heinze, J. (1984) ‘The electrochemical reduction of benzene. First direct determination of the reduction potential’, Angew. Chem. Int. Ed. Engl., 23, 84–85.

    Article  Google Scholar 

  27. Henton, D. R., McCreery, R. L., and Swenton, J. S. (1980) ‘Anodic oxidation of 1,4-dimethoxy aromatic compounds. A facile route to functionalized quinone bisketals’, J. Org. Chem., 45, 369–378.

    Article  CAS  Google Scholar 

  28. Fajer, J., Borg, D. C., Forman, A., Dolphin, D., and Felton, R. H. (1970) ‘π-Cation radicals and dications of metalloporphyrins’, J. Am. Chem. Soc., 92, 3451–3460.

    Article  PubMed  CAS  Google Scholar 

  29. Distances were determined from Corey-Pauling-Koltun molecular models.

    Google Scholar 

  30. Oliver, A. M., Craig, D. C, Paddon-Row, M. N., Kroon, J., and Verhoeven, J. W. (1988) ‘Strong effects of the bridge configuration on photoinduced charge separation in rigidly-linked donor-acceptor systems’, Chem. Phys. Lett., 150. 366–373.

    Article  CAS  Google Scholar 

  31. Closs, G. L., Calcaterra, L. T., Green, N. J., Penfield, K. W., and Miller, J. R. (1986) ‘Distance, stereoelectronic effects, and the Marcus inverted region in intramolecular electron transfer in organic radical anions’, J. Phys. Chem., 90, 3673–3683.

    Article  CAS  Google Scholar 

  32. Plato, M., Mobius, K., Michel-Beyerle, M. E., Bixon, M., and Jortner, J. (1988) ‘Intermodular electronic interactions in the primary charge separation in bacterial photosynthesis’, J. Am. Chem. Soc., 110, 7279–7285.

    Article  CAS  Google Scholar 

  33. Seybold, P. G. and Gouterman, M. (1969) ‘Porphyrins XIII: Fluorescence spectra and quantum yields’, J. Mol. Spectrosc, 31, 1–13.

    Article  CAS  Google Scholar 

  34. Wasielewski, M. R., Smith, R. L., and Kostka, A. G. (1980) ‘Electrochemical production of chlorophyll a and pheophytin a excited states’, J. Am. Chem. Soc., 102, 6923–6928.

    Article  CAS  Google Scholar 

Download references

Author information

Authors and Affiliations

  1. Chemistry Division, Argonne National Laboratory, Argonne, IL, 60439, USA

    Michael R. Wasielewski, Mark P. Niemczyk, Douglas G. Johnson, Walter A. Svec & David W. Minsek

Authors
  1. Michael R. Wasielewski
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Mark P. Niemczyk
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Douglas G. Johnson
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Walter A. Svec
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. David W. Minsek
    View author publications

    You can also search for this author in PubMed Google Scholar

Editor information

Editors and Affiliations

  1. Department of Chemistry, University of Tel-Aviv, Israel

    J. Jortner

  2. Institut de Biologie Physico-Chimique (Fondation Edmond de Rothschild), Paris, France

    B. Pullman

Rights and permissions

Reprints and permissions

Copyright information

© 1990 Kluwer Academic Publishers

About this paper

Cite this paper

Wasielewski, M.R., Niemczyk, M.P., Johnson, D.G., Svec, W.A., Minsek, D.W. (1990). Photosynthetic Model Systems That Address the Role of Superexchange in Electron Transfer Reactions. In: Jortner, J., Pullman, B. (eds) Perspectives in Photosynthesis. The Jerusalem Symposia on Quantum Chemistry and Biochemistry, vol 22. Springer, Dordrecht. https://doi.org/10.1007/978-94-009-0489-7_27

Download citation

  • DOI: https://doi.org/10.1007/978-94-009-0489-7_27

  • Publisher Name: Springer, Dordrecht

  • Print ISBN: 978-94-010-6706-5

  • Online ISBN: 978-94-009-0489-7

  • eBook Packages: Springer Book Archive

Publish with us

Policies and ethics

Search

Navigation