Abstract
The time constants for electron transfer from the singlet excited state of the small cavity conformer of the tetrabridged coplanar zinc porphyrin quinone (ZnPQ) average 2.4 times as fast in solvents containing XCCl3 group as in solvents of similar dielectric properties. Solvent molecules containing this bulky group cannot fit in the small cavity of conformer ZnPQa. We assign the effect to the increase of the electron wave function in the porphyrin-quinone space by increased exclusion from the electron dense solvent as compared to more usual solvents. We name this property the tamper effect.
Similar content being viewed by others
References
Axup AW, Albin M, Mayo SL, Crutchley RJ and Gray H (1988) Distance dependence of photoinduced long-range electron transfer in zinc/ruthenium-modified myoglobins. J Am Chem Soc 110: 435–439
Calef D and Wolynes P (1983) Classical solvent dynamics and electron transfer. I. Continuum Theory. J Phys Chem 87: 3387–3400
Closs GL and Miller J (1988) Intramolecular long-distance electron transfer in organic molecules. Science 240: 440–447
Connolly JS and Bolton JR (1988) Intramolecular Electron Transfer: History and Some Implications for Artificial Photosynthesis. In: Fox MA and Chanon M (eds) Photoinduced Electron Transfer, Part D, Chap 6.2, pp 303–393. Amsterdam: Elsevier
Delaney J, Mauzerall D and Lindsey J (1989) Electron tunneling in a cofacial zinc porphyrin quinone cage molecule: Novel temperature and solvent dependence. J Am Chem Soc (submitted)
DeVault D (1984) Quantum Mechanical Tunneling in Biological Systems, p 270. Cambridge: Cambridge University Press
Eaton GR and Eaton SS (1988) EPR studies of long-range intramolecular electron-electron exchange interaction. Acc Chem Res 21: 107–113
Hush N (1987) Photoinduced electron transfer through long rigid non-conjugated bridges: Theory and experiment for model systems. In: Balzani V (ed) Supramolecular Photochemistry, NATO ASI Series pp 53–72. Dordrecht Reidel
Isied S, Vassilian A and Wishart J (1988) The distance dependence of intramolecular electron-transfer rates: Importance of the nuclear factor. J Am Chem Soc 110: 635–637
Joran A, Leland B, Geller GG, Hopfield JJ and Dervan PB (1984) Models for photochemical electron-transfer at fixed distances-prophyrin bicyclo (2.2.2) octane-quinone and porphyrin-bibicyclo (2.2.2) octane-quinone. J Am Chem Soc 106: 6090–6092
Kakitani T and Mataga N (1985) Photoinduced electron transfer in polar solutions 2. New aspects of the role of the solvent mode in electron transfer processes in charge-recombination reactions and comparison with charge-separation reactions. J Phys Chem 89: 4752–4757
Karas JL, Lieber CM and Gray HB (1988) Free energy dependence of the rate of long-range electron transfer in proteins. Reorganization energy in Ruthenium-modified myoglobin. J Am Chem Soc 110: 599–602
Khairutdinov RF and Brickenstein KH (1986) Long range electron tunneling in biological and model systems. Photochem Photobiol 43: 339–356
Koziar JC and Cowan DO (1978) Photochemical heavy-atom effects. Acc Chem Res 11: 334–341
Lindsey J and Mauzerall D (1982) Synthesis of a cofacial porphyrin-quinone via entropically favoured macropolycyclization. J Am Chem Soc 104: 4498–4500
Lindsey J, Delaney J, Mauzerall D and Linschitz H (1988) Photophysics of a cofacial porphyrin-quinone cage molecule and related compounds: Fluorescence properties, flash transient and electron-transfer reactions. J Am Chem Soc 110: 3610–3621
Mauzerall D (1976) Electron-transfer reactions and photoexcited porphyrins. In: Chlorophyll-Proteins Reaction Centers and Photosynthetic Membranes, Brookhaven Symp Biol 28: 64–73
Mauzerall D (1985) Evidence that the variable fluorescence in Chlorella is recombination luminescence. Biochim Biophys Acta 809: 11–16
Mauzerall D, Weiser J and Staab H (1989) Electron transfer in photoexcited porphyrin quinone cyclophanes. Tetrahedron Lett (in press)
Mayo SL, EllisJr W, Crutchley R and Gray H (1986) Long range electron transfer in heme proteins. Science 233: 948–952
McLendon G (1988) Long distances electron transfer in proteins and model systems. Acc Chem Res 21: 160–167
Mikkelson KV and Ratner MA (1987) Electron tunneling in solid state electron-transfer reactions. Chem Rev 87: 113–153
Seely GR (1978) The energetics of electron transfer reactions of chlorophyll and other compounds. Photochem Photobiol 27: 638–654
Solovev KN, Tsvirko MP, Gradyushko AT and Kozhick D (1972) Internal effect of a heavy atom in porphyrin molecules. I. Halo derivatives of tetraphenylporphine. Optics and Spectr. 33: 480–483
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Delaney, J., Mauzerall, D. The tamper effect: environmental influence on electron tunneling. Photosynth Res 22, 195–199 (1989). https://doi.org/10.1007/BF00048298
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00048298