Abstract
In order to better understand the dependence of charge recombination rate vs. temperaturek CR(T) within a linear donor-chromophore-acceptor (D-C-A) molecular triad, the structural dynamics of the cation radical D+-C is studied individually using variable-temperature electron paramagnetic resonance (EPR) spectroscopy and electronic structure calculations. Here, the donor D isp-methoxyaniline, the chromophore C is 4-(N-piperidinyl)-naphthalene-1,8-dicarboximide, and the acceptor A is naphthalene-1,8∶4,5-bis(dicarboximide). The EPR spectra of D+-C exhibit marked changes in their overall shape throughout the 190–295 K temperature range. These spectra have hyperfine splittings that are strikingly well simulated with a model that includes methoxy group rotation, which occurs at a rate of 2.6 · 104 s−1 at 210 K and speeds up to 1.25 · 107 s−1 at 295 K, corresponding to an energy barrier of 38 kJ/mol. This considerable barrier reflects the partial conjugation between MeO and the aromatic ring and is confirmed by the calculated energy of a series of D+ ·-C rotamers. The simulations also reveal that inversion of the anilino N center emerges atT > 250 K and can be represented by a planar and a pyramidal conformation with the equilibrium constantK = [pyramidal]/[planar] increasing from 0.029 at 250 K to 0.56 at 295 K. In the same temperature range, the charge recombination rate of D+ ·-C-A− · accelerates abruptly and can be separated into two components, according to the above planar/pyramidal equilibrium. Thek CR (T) of the pyramidal conformation has an activation energy of 41 kJ/mol, virtually the same as the barrier of MeO rotation. These results show that the intramolecular structural dynamics of the radical cation within D+·-C-A− · control the overall charge recombination reaction with this radical ion pair.
Similar content being viewed by others
References
Plato M., Möbius K., Michel-Beyerle M.E., Bixon M., Jortner J.: J. Am. Chem. Soc.110, 7279–7285 (1988)
Deisenhofer J., Norris J.R. (eds.): The Photosynthetic Reaction Center. San Diego: Academic Press 1993.
Closs G.L>, Miller J.R.: Science240, 440–447 (1988)
Wasielewski M.R.: Chem. Rev.92, 435–461 (1992)
Gust D., Moore T.A., Moore A.L.: Acc. Chem. Res.26, 198–205 (1993)
Davis W.B., Svec W.A., Ratner M.A., Wasielewski M.R.: Nature396, 60–63 (1998)
Schmidt-Mende L., Fechtenkotter A., Müllen K., Moons E., Friend R.H., MacKenzie J.D.: Science293, 1119–1122 (2001)
Hoppe H., Sariciftci N.S.: J. Mater. Res.19, 1924–1945 (2004)
Weiss E.A., Tauber M.J., Kelley R.F., Ahrens M.J., Ratner M.A., Wasielewski M.R.: J. Am. Chem. Soc.127, 11842–11850 (2005)
Weiss E.A., Tauber M.J., Ratner M.A., Wasielewski M.R.: J. Am. Chem. Soc.127, 6052–6061 (2005)
Greenfield S.R., Svec W.A., Gosztola D., Wasielewski M.R.: J. Am. Chem. Soc.118, 6767–6777 (1996)
Hasharoni K., Levanon H., Greenfield S.R., Gosztola D.J., Svec W.A., Wasielewski M.R.: J. Am. Chem. Soc.118, 10228–10235 (1996)
Lukas A.S., Bushard P.J., Weiss E.A., Wasielewski M.R.: J. Am. Chem. Soc.125, 3921–3930 (2003)
Shaakov S., Galili T., Stavitski E., Levanon H., Lukas A., Wasielewski M.R.: J. Am. Chem. Soc. 125, 6563–6572 (2003)
Weiss E.A., Ratner M.A., Wasielewski M.R.: J. Phys. Chem. A107, 3639–3647 (2003)
Weiss E.A., Chernick E.T., Wasielewski M.R.: J. Am. Chem. Soc.126, 2326–2327 (2004)
Mi Q., Chernick E.T., McCamant D.W., Weiss E.A., Ratner M.A., Wasielewski M.R.: J. Phys. Chem. A110, 7323–7333 (2006)
Chernick E.T., Mi Q., Kelley R.F., Weiss E.A., Jones B.A., Marks T.J., Ratner M.A., Wasielewski M.R.: J. Am. Chem. Soc.128, 4356–4364 (2006)
Dutton P.L., Seibert M., Leigh J.S.: Biochem. Biophys. Res. Commun.46, 406–413 (1972)
Smirnov S.N., Braun C.L.: Rev. Sci. Instrum69, 2875–2887 (1998)
Muus L.T., Atkins P.W., McLauchlan K.A., Pedersen J.B. (eds.): Chemically Induced Magnetic Polarization. Dordrecht: Reidel 1977.
Closs G.L., Forbes M.D.E., Norris J.R.: J. Phys. Chem.91, 3592–3599 (1987)
Prisner T., Dobbert O., Dinse K.P., Van Willigen H.: J. Am. Chem. Soc.110, 1622–1623 (1988)
Kothe G., Weber S., Ohmes E., Thurnauer M.C., Norris J.R.: J. Am. Chem. Soc.116, 7729–7734 (1994)
Zech S.G., Bittl R., Gardiner A.T., Lubitz W.: Appl. Magn. Reson.13, 517–529 (1997)
Berliner L.J., Eaton G.R., Eaton S.S. (eds.): Distance Measurements in Biological Systems by EPR. Biological Magnetic Resonance, vol. 19. New York: Kluwer Academic Plenum 2000.
Wegener C., Savitsky A., Pfeiffer M., Möbius K., Steinhoff H.J.: Appl. Magn. Reson.21, 441–452 (2001)
Möbius K., Savitsky A., Wegener C., Rato M., Fuchs M., Schnegg A., Dubinskii A.A., Grishin Y.A., Grigor’ev I.A., Kuhn M., Duche D., Zimmermann H., Steinhoff H.J.: Magn. Reson. Chem.43, S4-S19 (2005)
Schneider D.J., Freed J.H.: Adv. Chem. Phys.73, 387–527 (1989)
Kothe G., Weber S., Ohmes E., Thurnauer M.C., Norris J.R.: J. Phys. Chem.98, 2706–2712 (1994)
Polimeno A., Zerbetto M., Franco L., Maggini M., Corvaja C.: J. Am. Chem. Soc.128, 4734–4741 (2006)
Shine H.J., Padilla A.G., Wu S.M.: J. Org. Chem.44, 4069–4075 (1979)
Kass H., Bittersmann-Weidlich E., Andreasson L.E., Bonigk B., Lubitz W.: Chem. Phys.194, 419–432 (1995)
Gaussian 98, Revision A.7. Frisch M.J., Trucks G.W., Schlegel H.B., Scuseria G.E., Robb M.A., Cheeseman J.R., Zakrzewski V.G., Montgomery J.A. Jr., Stratmann R.E., Burant J.C., Dapprich S., Millam J.M., Daniels A.D., Kudin K.N., Strain M.C., Farkas O., Tomasi J., Barone V., Cossi M., Cammi R., Mennucci B., Pomelli C., Adamo C., Clifford S., Ochterski J., Petersson G.A. Ayala P.Y., Cui Q., Morokuma K., Malick D.K., Rabuck A.D., Raghavachari K., Foresman J.B., Cioslowski J., Ortiz J.V., Baboul A.G., Stefanov B.B., Liu G., Liashenko A., Piskorz P., Komaromi I., Gomperts R., Martin R.L., Fox D.J., Keith T., Al-Laham M.A., Peng C.Y., Nanayakkara A., Gonzalez C., Challacombe M., Gill P.M.W., Johnson B., Chen W., Wong M.W., Andres J.L., Gonzalez C., Head-Gordon M., Replogle E.S., Pople J.A. Pittsburgh, Pa.: Gaussian, Inc. 1998.
Becke A.D.: J. Chem. Phys.98, 5648–5652 (1993)
Lee C.T., Yang W.T., Parr R.G.: Phys. Rev. B37, 785–789 (1988)
Barone V. in: Recent Advances in Density Functional Methods (Chong D.P., ed.), vol. 1, pp. 287–334. Singapore: World Scientific 1995.
Duling D.R.: J. Magn. Reson. B104, 105–110 (1994)
Carrington A., McLachlan A.D.: Introduction to Magnetic Resonance with Applications to Chemistry and Chemical Physics, pp. 205–208. New York: Harper and Row 1967.
Gosztola D., Niemczyk M.P., Svec W., Lukas A.S., Wasielewski M.R.: J. Phys. Chem. A104, 6545–6551 (2000)
Mes G.F., Vanramesdonk H.J., Verhoeven J.W.: J. Am. Chem. Soc.106, 1335–1340 (1984)
Gerson F., Huber W.: Electron Spin Resonance Spectroscopy of Organic Radicals, pp. 61–64. Weinheim: Wiley-VCH 2003.
Marcus R.A.: J. Chem. Phys.43, 679–701 (1965)
Marcus R.A.: J. Chem. Phys.24, 966–978 (1956)
Schatz G.C., Ratner M.A.: Quantum Mechanics in Chemistry, pp. 216–218. Mineola, N.Y.: Dover Publications 2002.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Mi, Q., Weiss, E.A., Ratner, M.A. et al. Influence of structural dynamics on charge recombination rates in photogenerated radical ion pairs: Evidence from EPR spectroscopy and computation. Appl. Magn. Reson. 31, 253–270 (2007). https://doi.org/10.1007/BF03166260
Received:
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF03166260