Low field photo-CIDNP in the intramolecular electron transfer in naproxen-pyrrolidine dyads

[EN] Photoinduced processes with partial (exciplex) and full charge transfer in donor-acceptor systems are of interest because they are frequently used for modeling drug-protein binding. Low field photo-CIDNP (chemically induced dynamic nuclear polarization) for these processes in dyads, including the drug, (S)-and (R)-naproxen and (S)-N-methyl pyrrolidine in solutions with strong and weak permittivity have been measured. The dramatic influence of solvent permittivity on the field dependence of the N-methyl pyrrolidine H-1 CIDNP effects has been found. The field dependences of both (R, S)-and (S, S)-dyads in a polar medium are the curves with a single extremum in the area of the S-T+ terms intersection. Moreover, the CIDNP field dependences of the same protons measured in a low polar medium present curves with several extrema. The shapes of the experimental CIDNP field dependence with two extrema have been described using the Green function approach for the calculation of the CIDNP effects in the system without electron exchange interactions. The article discusses the possible causes of the differences between the CIDNP field dependence detected in a low-permittivity solvent with the strong Coulomb interactions and in a polar solvent.This study was supported by the grant 14-03-00-192 of the Russian Foundation of Basic Research. The authors are also deeply grateful to Professor Hans-Martin Vieth for the given opportunity to conduct experiments on his unique equipment.Magin, I.; Polyakov, N.; Kruppa, AI.; Purtov, P.; Leshina, TV.; Kiryutin, AS.; Miranda Alonso, MÁ.... (2016). Low field photo-CIDNP in the intramolecular electron transfer in naproxen-pyrrolidine dyads. Physical Chemistry Chemical Physics. 18(2):901-907. https://doi.org/10.1039/C5CP04233J901907182Reece, S. Y., & Nocera, D. G. (2009). Proton-Coupled Electron Transfer in Biology: Results from Synergistic Studies in Natural and Model Systems. Annual Review of Biochemistry, 78(1), 673-699. doi:10.1146/annurev.biochem.78.080207.092132Richert, S., Rosspeintner, A., Landgraf, S., Grampp, G., Vauthey, E., & Kattnig, D. R. (2013). Time-Resolved Magnetic Field Effects Distinguish Loose Ion Pairs from Exciplexes. Journal of the American Chemical Society, 135(40), 15144-15152. doi:10.1021/ja407052tAich, S., & Basu, S. (1998). Magnetic Field Effect: A Tool for Identification of Spin State in a Photoinduced Electron-Transfer Reaction. The Journal of Physical Chemistry A, 102(4), 722-729. doi:10.1021/jp972264mVayá, I., Pérez-Ruiz, R., Lhiaubet-Vallet, V., Jiménez, M. C., & Miranda, M. A. (2010). Drug–protein interactions assessed by fluorescence measurements in the real complexes and in model dyads. Chemical Physics Letters, 486(4-6), 147-153. doi:10.1016/j.cplett.2009.12.091Werner, U., & Staerk, H. (1995). Magnetic Field Effect in the Recombination Reaction of Radical Ion Pairs: Dependence on Solvent Dielectric Constant. The Journal of Physical Chemistry, 99(1), 248-254. doi:10.1021/j100001a038Kattnig, D. R., Rosspeintner, A., & Grampp, G. (2008). Fully Reversible Interconversion between Locally Excited Fluorophore, Exciplex, and Radical Ion Pair Demonstrated by a New Magnetic Field Effect. Angewandte Chemie International Edition, 47(5), 960-962. doi:10.1002/anie.200703488Kattnig, D. R., Rosspeintner, A., & Grampp, G. (2011). Magnetic field effects on exciplex-forming systems: the effect on the locally excited fluorophore and its dependence on free energy. Phys. Chem. Chem. Phys., 13(8), 3446-3460. doi:10.1039/c0cp01517bVayá, I., Lhiaubet-Vallet, V., Jiménez, M. C., & Miranda, M. A. (2014). Photoactive assemblies of organic compounds and biomolecules: drug–protein supramolecular systems. Chem. Soc. Rev., 43(12), 4102-4122. doi:10.1039/c3cs60413fPolyakov, N. E., Taraban, M. B., & Leshina, T. V. (2004). Photo-CIDNP Study of the Interaction of Tyrosine with Nifedipine. An Attempt to Model the Binding Between Calcium Receptor and Calcium Antagonist Nifedipine¶. Photochemistry and Photobiology, 80(3), 565. doi:10.1562/0031-8655(2004)0802.0.co;2Cao, H., Fujiwara, Y., Haino, T., Fukazawa, Y., Tung, C.-H., & Tanimoto, Y. (1996). Magnetic Field Effects on Intramolecular Exciplex Fluorescence of Chain-Linked Phenanthrene andN,N-Dimethylaniline: Influence of Chain Length, Solvent, and Temperature. Bulletin of the Chemical Society of Japan, 69(10), 2801-2813. doi:10.1246/bcsj.69.2801Magin, I. M., Polyakov, N. E., Khramtsova, E. A., Kruppa, A. I., Tsentalovich, Y. P., Leshina, T. V., … Marin, M. L. (2011). Spin effects in intramolecular electron transfer in naproxen-N-methylpyrrolidine dyad. Chemical Physics Letters, 516(1-3), 51-55. doi:10.1016/j.cplett.2011.09.057Khramtsova, E. A., Plyusnin, V. F., Magin, I. M., Kruppa, A. I., Polyakov, N. E., Leshina, T. V., … Miranda, M. A. (2013). Time-Resolved Fluorescence Study of Exciplex Formation in Diastereomeric Naproxen–Pyrrolidine Dyads. The Journal of Physical Chemistry B, 117(50), 16206-16211. doi:10.1021/jp4083147Magin, I. M., Purtov, P. A., Kruppa, A. I., & Leshina, T. V. (2005). Peculiarities of Magnetic and Spin Effects in a Biradical/Stable Radical Complex (Three-Spin System). Theory and Comparison with Experiment. The Journal of Physical Chemistry A, 109(33), 7396-7401. doi:10.1021/jp051115ySubramanian, V., Bellubbi, B. S., & Sobhanadri, J. (1993). Dielectric studies of some binary liquid mixtures using microwave cavity techniques. Pramana, 41(1), 9-20. doi:10.1007/bf02847313Acemioğlu, B., Arık, M., Efeoğlu, H., & Onganer, Y. (2001). Solvent effect on the ground and excited state dipole moments of fluorescein. Journal of Molecular Structure: THEOCHEM, 548(1-3), 165-171. doi:10.1016/s0166-1280(01)00513-9Grosse, S., Gubaydullin, F., Scheelken, H., Vieth, H.-M., & Yurkovskaya, A. V. (1999). Field cycling by fast NMR probe transfer: Design and application in field-dependent CIDNP experiments. Applied Magnetic Resonance, 17(2-3), 211-225. doi:10.1007/bf03162162Magin, I. M., Polyakov, N. E., Khramtsova, E. A., Kruppa, A. I., Stepanov, A. A., Purtov, P. A., … Marin, M. L. (2011). Spin Chemistry Investigation of Peculiarities of Photoinduced Electron Transfer in Donor–Acceptor Linked System. Applied Magnetic Resonance, 41(2-4), 205-220. doi:10.1007/s00723-011-0288-3C. K. Mann and K. K.Barnes, Electrochemical Reactions in Nonaqueous Systems, M. Dekker, New York, 1970N. S. Landolt-Bornstein , Numerical Data and Functional Relationship in Science and Technology: Magnetic Properties of Free Radicals, Springer-Verlag, Berlin, 1988Grigoryants, V. M., Anisimov, O. A., & Molin, Y. N. (1982). Study of the radical-cations of triethylamine and benzene derivatives by the optical detection of the EPR spectra of radical-ion Pairs. Journal of Structural Chemistry, 23(3), 327-333. doi:10.1007/bf00753466Bargon, J. (1977). CIDNP from geminate recombination of radical-ion pairs in polar solvents. Journal of the American Chemical Society, 99(25), 8350-8351. doi:10.1021/ja00467a054Purtov, P. A., & Doktorov, A. B. (1993). The Green function method in the theory of nuclear and electron spin polarization. I. General theory, zero approximation and applications. Chemical Physics, 178(1-3), 47-65. doi:10.1016/0301-0104(93)85050-iPurtov, P. A., Doktorov, A. B., & Popov, A. V. (1994). The green function method in the theory of nuclear and electron spin polarization. II. The first approximation and its application in the CIDEP theory. Chemical Physics, 182(2-3), 149-166. doi:10.1016/0301-0104(93)e0449-6K. M. Salikhov , Yu. N.Molin, R. Z.Sagdeev and A. L.Buchachenko, in Spin Polarization and Magnetic Field Effects in Radical, ed. Yu. N. Molin, Akademiai Kiado, Budapest, 1984Polyakov, N. E., Purtov, P. A., Leshina, T. V., Taraban, M. B., Sagdeev, R. Z., & Salikhov, K. M. (1986). Application of the semiclassical description of hyperfine interaction to studies of the dependence of the CIDNP effect on an external magnetic field. Chemical Physics Letters, 129(4), 357-361. doi:10.1016/0009-2614(86)80358-xShiotani, M., Sjoeqvist, L., Lund, A., Lunell, S., Eriksson, L., & Huang, M. B. (1990). An ESR and theoretical ab initio study of the structure and dynamics of the pyrrolidine radical cation and the neutral 1-pyrrolidinyl radical. The Journal of Physical Chemistry, 94(21), 8081-8090. doi:10.1021/j100384a020De Kanter, F. J. J., den Hollander, J. A., Huizer, A. H., & Kaptein, R. (1977). Biradical CIDNP and the dynamics of polymethylene chains. Molecular Physics, 34(3), 857-874. doi:10.1080/00268977700102161De Kanter, F. J. J., Kaptein, R., & Van Santen, R. A. (1977). Magnetic field dependent biradical CIDNP as a tool for the study of conformations of polymethylene chains. Chemical Physics Letters, 45(3), 575-579. doi:10.1016/0009-2614(77)80093-6Tsentalovich, Y. P., Yurkovskaya, A. V., Sagdeev, R. Z., Obynochny, A. A., Purtov, P. A., & Shargorodsky, A. A. (1989). Kinetics of nuclear polarization in the geminate recombination of biradicals. Chemical Physics, 139(2-3), 307-315. doi:10.1016/0301-0104(89)80143-0Popov, A. V., Purtov, P. A., & Yurkovskaya, A. V. (2000). Calculation of CIDNP field dependences in biradicals in the photolysis of large-ring cycloalkanones. Chemical Physics, 252(1-2), 83-95. doi:10.1016/s0301-0104(99)00293-1Magin, I. M., Shevel’kov, V. S., Obynochny, A. A., Kruppa, A. I., & Leshina, T. V. (2002). CIDNP study of the third spin effect on the singlet–triplet evolution in radical pairs. Chemical Physics Letters, 357(5-6), 351-357. doi:10.1016/s0009-2614(02)00544-4Schulten, K., & Wolynes, P. G. (1978). Semiclassical description of electron spin motion in radicals including the effect of electron hopping. The Journal of Chemical Physics, 68(7), 3292-3297. doi:10.1063/1.436135Kalneus, E. V., Stass, D. V., & Molin, Y. N. (2005). Typical applications of MARY spectroscopy: Radical ions of substituted benzenes. Applied Magnetic Resonance, 28(3-4), 213-229. doi:10.1007/bf03166757Kruppa, A. I., Leshina, T. V., Sagdeev, R. Z., Korolenko, E. C., & Shokhirev, N. V. (1987). Low-field CIDNP study of photoinduced electron transfer reactions. Chemical Physics, 114(1), 95-101. doi:10.1016/0301-0104(87)80022-