Solvent Radical Anions in Irradiated Aliphatic Ketones and Esters as Observed Using Time-Resolved Magnetic Field Effects in the Recombination Fluorescence
-
Vsevolod Borovkov
,
Andrey Taratayko
Abstract
It has been found that addition of alcohols (~0.1 M) to some liquid ketones and esters results in well-pronounced oscillations in the decay of the delayed fluorescence intensity from irradiated solutions. The analysis of the time-resolved magnetic field effects (TR MFEs) in the recombination fluorescence has shown that these oscillations are a manifestation of singlet-triplet transitions in spin-correlated radical ion pairs (RIPs) created by irradiation. Comparison with literature data indicates that the transitions are due to hyperfine couplings (HFCs) in the solvent radical anion (RA), stabilized due to the presence of alcohol molecules. In acetone, this stabilization effect has been observed for methanol, ethanol, 2- propanol, and, to a smaller extent, for tert-butanol. Similar effects have also been observed in diethyl ketone, ethyl acetate, and methyl propionate but not in methyl tert-butyl ketone and ethyl trimethylacetate. The results obtained indicate that the interaction between the radical anions (RAs) of carbonyl compounds and alcohol molecules is of importance in pulse radiolysis studies of organic liquids and their mixtures.
Dedicated to: Kev Salikhov on the occasion of his 80th birthday.
Acknowledgements
This work was supported by the Russian Foundation for Basic Researches (Grant 14-03-00570).
Appendix A
When the fluorescence time is short, the intensity of recombination fluorescence in nonpolar solutions is proportional to the recombination rate of the RIPs, F(t), multiplied by the singlet state population of RIPs ensemble [15], [16]:
where ρss(t) is the time dependence of the singlet state population of the initially singlet-correlated RIPs. θ is a semiempirical parameter to take into account the fact that in a multiparticle radiation spur only a fraction of recombining RIPs is spin-correlated, whereas some of them are composed of radical ions originating from different primary ionization events. The second term in the brackets takes account of such spin-uncorrelated RIPs.
In this approximation, the TR MFE curve,
depends only on the singlet state populations of the spin-correlated RIPs, ρss(t), in non-zero and zero external magnetic fields as indicated by superscripts B and 0, respectively. The ρss(t) dependence can be evaluated taking the paramagnetic relaxation into account as previously suggested [15]:
where 1/T1,2=1/T(a)+1/T(c)1,2 are the sums of the longitudinal or phase relaxation rates of the RIP partners, and T0 is the parameter to describe phase relaxation of the RIP in a zero magnetic field in the same manner. Subscripts “a” and “c” point to the parameters of RA and RC, respectively.
The analytical solutions to G0,B(t) are known only for some particular cases: the case of groups of equivalent magnetic nuclei and the case of a large number of nonequivalent magnetic nuclei. For a large of magnetic nuclei having different HFC constants that is the case of radical ions of para-terphenyl, in the framework of the semi-classical approximation, the functions G(t) are (in magnetic field units for σ and a) [29],
where σ2 is the second momentum of the radical ion EPR spectrum, γ is the electron gyromagnetic ratio.
For n magneto-equivalent protons with the HFC constant a [22],
References
1. G. L. Bolton, M. G. Robinson, G. R. Freeman. Can. J. Chem. 54 (1976) 1177.10.1139/v76-167Search in Google Scholar
2. F. Torche, A. K. El Omar, P. Babilotte, S. Sorgues, U. Schmidhammer, J. L. Marignier, M. Mostafavi, J. Belloni. J. Phys. Chem. A 117 (2013) 10801.10.1021/jp406856uSearch in Google Scholar
3. M. A. J. Rodgers. J. Chem. Soc. Faraday Trans. I 68 (1972)1278.10.1039/f19726801278Search in Google Scholar
4. A. J. Robinson, M. A. J. Rodgers. J. Chem. Soc. Faraday Trans. I 69 (1973) 2036.10.1039/f19736902036Search in Google Scholar
5. R. Lomoth, S. Naumov, O. Brede. J. Phys. Chem. A 103 (1999) 2641.10.1021/jp9829804Search in Google Scholar
6. G. Ramanan. J. Phys. Chem. 80 (1976) 1553.10.1021/j100555a007Search in Google Scholar
7. K. D. Jordan, P. D. Burrow. Acc. Chem. Res. 11 (1978) 341.10.1021/ar50129a004Search in Google Scholar
8. J. Simons. J. Phys. Chem. A 112 (2008) 6401.10.1021/jp711490bSearch in Google Scholar
9. I. Fourre, B. Silvi, P. Chaquin, A. Sevin. J. Comput. Chem. 20 (1999) 897.10.1002/(SICI)1096-987X(19990715)20:9<897::AID-JCC1>3.0.CO;2-4Search in Google Scholar
10. R. Nakanishi, A. Muraoka, T. Nagata. Chem. Phys. Letters 427 (2006) 56.10.1016/j.cplett.2006.06.061Search in Google Scholar
11. E. V. Saenko, D. N. Laikov, I. A. Baranova, V. I. Feldman. J. Chem. Phys. 135 (2011) 101103.10.1063/1.3638690Search in Google Scholar
12. A. G. Davies, A. G. Neville. J. Chem. Soc. Perkin Trans. 2, (1992) 163.10.1039/p29920000163Search in Google Scholar
13. P. B. Ayscough, J. P. Oversby. J. Chem. Soc. Faraday Trans. 1, 68 (1972) 1153.10.1039/f19726801153Search in Google Scholar
14. R. Köppe, P. H. Kasai. Chem. Phys. 189 (1994) 401.10.1016/0301-0104(94)00142-1Search in Google Scholar
15. V. A. Bagryansky, V. I. Borovkov, Yu. N. Molin. Russ. Chem. Rev. 76 (2007) 493.10.1070/RC2007v076n06ABEH003715Search in Google Scholar
16. V. Borovkov, D. Stass, V. Bagryansky, Y. Molin. In: Applications of EPR in Radiation Research. A. Lund, M. Shiotani (Eds.), Springer International Publishing (2014), Ch. 17, 629.10.1007/978-3-319-09216-4_17Search in Google Scholar
17. P. A. Potashov, V. I. Borovkov, L. N. Shchegoleva, N. P. Gritsan, V. A. Bagryansky, Y. N. Molin. J. Phys. Chem. A. 116 (2012) 3110.10.1021/jp2113208Search in Google Scholar
18. V. I. Borovkov, I. V. Beregovaya, L. N. Shchegoleva, S. V. Blinkova, D. A. Ovchinnikov, L. Y. Gurskaya, V. D. Shteingarts, V. A. Bagryansky, Y. N. Molin. J. Phys. Chem. A 119 (2015) 8443.10.1021/acs.jpca.5b02617Search in Google Scholar
19. K. S. Taletskiy, V. I. Borovkov, L. N. Schegoleva, I. V. Beregovaya, A. I. Taratayko, Y. N. Molin. J. Phys. Chem. B 119 (2015) 14472.10.1021/acs.jpcb.5b06086Search in Google Scholar
20. S. V. Anishchik, V. M. Grigoryantz, I. V. Shebolaev, Y. D. Chernousov, O. A. Anisimov, Y. N. Molin. Instrum. Exp. Tech. 32 (1989) 813.Search in Google Scholar
21. A. J. Gordon, R. A. Ford. The Chemist’s Companion, John Wiley & Sons, New York (1973), P. 560.Search in Google Scholar
22. V. A. Bagryansky, O. M. Usov, V. I. Borovkov, T. V. Kobzeva, Y. N. Molin. Chem. Phys. 255 (2000) 237.10.1016/S0301-0104(00)00078-1Search in Google Scholar
23. P. J. Boon, L. Harris, M. T. Olm, J. L. Wyatt, M. C. R. Symons. Chem. Phys. Letters 106 (1984) 408.10.1016/0009-2614(84)85328-2Search in Google Scholar
24. V. I. Feldman, F. Sukhov, A. Orlov, I. Tyulpina. Phys. Chem. Chem. Phys. 5 (2003) 1769.10.1039/b300111cSearch in Google Scholar
25. J. L. Courtneidge, A. G. Davies, D. C. McGuchan, Recl. Trav. Chim. Pays-Bas 107 (1988) 190.10.1002/recl.19881070317Search in Google Scholar
26. M. D. Seviila, K. M. Morehouse, S. Swarts. J. Phys. Chem. 85 (1981) 923.10.1021/j150607a038Search in Google Scholar
27. J. Haofang, W. Jilan, P. Xianming, Z. Xujia. Radiat. Phys. Chem. 47 (1996) 555.10.1016/0969-806X(95)00064-5Search in Google Scholar
28. I. Yagi, T. Maeyama, A. Fujii, N. Mikami. J. Phys. Chem. A 111 (2007) 7646.10.1021/jp072167lSearch in Google Scholar PubMed
29. K. Schulten, P. G. Wolynes. J. Chem. Phys. 68 (1978) 3292.10.1063/1.436135Search in Google Scholar
©2017 Walter de Gruyter GmbH, Berlin/Boston
Articles in the same Issue
- Frontmatter
- Preface
- Editorial Review
- From Free Radicals and Spin-Chemistry Over Spin-Dynamics and Hyperpolarization to Biology and Materials Science
- On Relations Between Singlet and Triplet Recombination Yields for Singlet and Triplet Precursors
- The Quantum Dynamical Basis of a Classical Kinetic Scheme Describing Coherent and Incoherent Regimes of Radical Pair Recombination
- Reaction Operators for Radical Pairs. The Exactly Solvable Model
- Estimation of the Fraction of Spin-Correlated Radical Ion Pairs in Irradiated Alkanes using Magnetosensitive Recombination Luminescence from Exciplexes Generated upon Recombination of a Probe Pair
- Theoretical Description of Pulsed RYDMR: Refocusing Zero-Quantum and Single Quantum Coherences
- A Transient EPR Study of Electron Transfer in Tetrathiafulvalene-Aluminum(III) Porphyrin-Anthraquinone Supramolecular Triads
- Solvent Radical Anions in Irradiated Aliphatic Ketones and Esters as Observed Using Time-Resolved Magnetic Field Effects in the Recombination Fluorescence
- Effect of Dehydrated Trehalose Matrix on the Kinetics of Forward Electron Transfer Reactions in Photosystem I
- Photo-CIDNP in the Reaction Center of the Diatom Cyclotella meneghiniana Observed by 13C MAS NMR
- Light-Stimulated Generation of Free Radicals by Quinones-Chelators
- Influence of C2-Methylation of Imidazolium Based Ionic Liquids on Photoinduced Spin Dynamics of the Dissolved ZnTPP Studied by Time-Resolved EPR
- ESR Study of Electron States in Ge/Si Heterostructures with Nanodisc Shaped Quantum Dots
- Novel Anthrathiophene-Based Small Molecules as Donor Material for Organic Photovoltaics: Synthesis and Light-Induced EPR Study
- Structural Determination of a DNA Oligomer for a Molecular Spin Qubit Lloyd Model of Quantum Computers
Articles in the same Issue
- Frontmatter
- Preface
- Editorial Review
- From Free Radicals and Spin-Chemistry Over Spin-Dynamics and Hyperpolarization to Biology and Materials Science
- On Relations Between Singlet and Triplet Recombination Yields for Singlet and Triplet Precursors
- The Quantum Dynamical Basis of a Classical Kinetic Scheme Describing Coherent and Incoherent Regimes of Radical Pair Recombination
- Reaction Operators for Radical Pairs. The Exactly Solvable Model
- Estimation of the Fraction of Spin-Correlated Radical Ion Pairs in Irradiated Alkanes using Magnetosensitive Recombination Luminescence from Exciplexes Generated upon Recombination of a Probe Pair
- Theoretical Description of Pulsed RYDMR: Refocusing Zero-Quantum and Single Quantum Coherences
- A Transient EPR Study of Electron Transfer in Tetrathiafulvalene-Aluminum(III) Porphyrin-Anthraquinone Supramolecular Triads
- Solvent Radical Anions in Irradiated Aliphatic Ketones and Esters as Observed Using Time-Resolved Magnetic Field Effects in the Recombination Fluorescence
- Effect of Dehydrated Trehalose Matrix on the Kinetics of Forward Electron Transfer Reactions in Photosystem I
- Photo-CIDNP in the Reaction Center of the Diatom Cyclotella meneghiniana Observed by 13C MAS NMR
- Light-Stimulated Generation of Free Radicals by Quinones-Chelators
- Influence of C2-Methylation of Imidazolium Based Ionic Liquids on Photoinduced Spin Dynamics of the Dissolved ZnTPP Studied by Time-Resolved EPR
- ESR Study of Electron States in Ge/Si Heterostructures with Nanodisc Shaped Quantum Dots
- Novel Anthrathiophene-Based Small Molecules as Donor Material for Organic Photovoltaics: Synthesis and Light-Induced EPR Study
- Structural Determination of a DNA Oligomer for a Molecular Spin Qubit Lloyd Model of Quantum Computers
