Donor-Acceptor (Electronic) Coupling in the Precursor Complex to Organic Electron Transfer: Intermolecular and Intramolecular Self-Exchange between Phenothiazine Redox Centers

Journal of the American Chemical Society

Volumn 126, Issue 5, 2004, Pages 1388-1401

  Sun, Duoli ^a   Rosokha, Sergiy V ^a   Kochi, Jay K ^a  

^a University of Houston   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

CHARGE TRANSFER; CHEMICAL ACTIVATION; POSITIVE IONS; RATE CONSTANTS; REDOX REACTIONS;

ELECTRONIC COUPLING; INTERMOLECULAR ELECTRON TRANSFER (ET);

ELECTRON TRANSITIONS;

CATION; ORTHO XYLENE; PHENOTHIAZINE; RADICAL;

ARTICLE; CYCLIC POTENTIOMETRY; ELECTROCHEMISTRY; ELECTRON SPIN RESONANCE; ELECTRON TRANSPORT; OXIDATION REDUCTION REACTION; REACTION TIME; TEMPERATURE DEPENDENCE; THERMODYNAMICS; ULTRAVIOLET SPECTROSCOPY; X RAY CRYSTALLOGRAPHY;

EID: 1042288185     PISSN: 00027863     EISSN: None     Source Type: Journal    
DOI: 10.1021/ja038746v     Document Type: Article

References (140)

1. (a) Marcus, R. A. Angew. Chem., Int. Ed. Engl. 1993, 32, 1111.
2. (b) Marcus, R. A. Discuss. Faraday Soc. 1960, 29, 21.
3. (c) Marcus, R. A. J. Phys. Chem. 1963, 67, 853.
4. (d) Marcus, R. A. J. Chem. Phys. 1965, 43, 679.
5. (e) Marcus, R. A.; Sutin, N. Biochim. Biophys. Acta 1985, 811, 265.
6. Sutin, N. Prog. Inorg. Chem. 1983, 30, 441.
7. (a) Newton, M. D. In Electron Transfer in Chemistry; Balzani, V., Ed.: Wiley-VCH: New York, 2001; Vol. 1, p 3.
8. (b) Astruc, D. Electron Transfer and Radical Processes in Transition-Metal Chemistry; Wiley-VCH: New York, 1995.
9. (c) Cannon, R. D. Electron-Transfer Reactions: Butterworth: London, 1980.
10. Eberson, L. Electron-Transfer Reactions in Organic Chemistry; Springer-Verlag: New York, 1987.
11. Eberson, L.; Shaik, S. S. J. Am. Chem. Soc. 1990, 112, 4484.
12. Nelsen, S.; Pladziewicz, J. Acc. Chem. Res. 2002, 35, 247.
13. (a) Such an upper limit of the electronic coupling element is rather arbitrary since it depends on the reorganization energy. See: Nelsen, S. In Electron Transfer in Chemistry, Balzani, V., Ed.; Wiley-VCH: New York, 2001; Vol. 1. p 342.
14. 3a and underscores another example of the never-ending rivalry between MO and VB treatments. See: Hoffmann, R.; Shaik, S. ; Hiberty, P. C. Acc. Chem. Res. 2003, 36, 750.
15. (a) Brunschwig, B. S.; Sutin, N. In Electron Transfer in Chemistry, Balzani, V., Ed.; Wiley-VCH: New York, 2001; Vol. 1, p 583.
16. (b) Brunschwig, B. S.; Sutin, N. Coord. Chem. Rev. 1999, 187, 233.
17. (c) Sutin, N. Adv. Chem. Phys. 1999, 106, 7.
18. (d) Creutz, C.; Newton, M. D.; Sutin, N. J. Photochem. Photobiol., A 1994, 82, 47.
19. See Eberson in ref 4. p 44.
20. .+ attendant upon one-electron oxidation. The latter also points to the mechanistic advantage accrued in a more general context by the use of "infinitely" variable organic structures for electron-transfer studies.
21. (a) Chen, P.; Duesing, R.; Graff, D. K.; Meyer, T. J. J. Phys. Chem. 1991, 95, 5850.
22. (b) Ohno, T.; Yoshimura, A.; Mataga, N. J. Phys. Chem. 1990, 94, 4871.
23. (c) Pelizzetti, E.; Giordano, R. J. Chem. Soc., Dalton Trans. 1979, 1516.
24. (d) Sorensen, S. P.; Bruning, W. H. J. Am. Chem. Soc. 1973, 95, 2445.
25. (e) Nath, S.; Singh, A. K.; Palit, D. K.; Sapre, A. V.; Mittal, J. P. J. Phys. Chem. A 2001, 105, 7151.
26. (f) Daub, J.; Engl, R.; Kurzawa, J.; Miller, S. E.; Schneider, S.; Stockmann, A.; Wasielewski, M. R. J. Phys. Chem. A 2001, 105, 5655.
27. (g) Shimada, E.; Nagano, M.; Iwahashi, M.: Mori, Y.; Sakaguchi, Y.; Hayashi, H. J. Phys. Chem. A 2001, 105, 2997.
28. (h) Reid, G. D.; Whittaker, D. J.; Day, M. A.; Creely, C. M.; Tuite, E. M.; Kelly, J.; Beddard, G. S. J. Am. Chem. Soc. 2001, 123, 6953.
29. (i) Larson, S. L.; Elliott, C. M.; Kelley, D. F. Inorg. Chem. 1996, 35, 2070.
30. (j) Larson, S. L.; Cooley, L. F.; Elliott, C. M.; Kelley, D. F. J. Am. Chem. Soc. 1992, 114, 9504.
31. (k) Borowitz, P.; Herbich, J.; Kapturkiewicz, A.; Opallo, M.; Nowacki, J. Chem. Phys. 1999, 249, 49.
32. (l) Kramer, C. S.; Zeutler, K.; Müller, T. J. J. Tetrahedron Lett. 2001, 49, 8619.
33. (a) Kawai, K.; Takada, T.; Tojo, S.; Majima, T. J. Am. Chem. Soc. 2003, 125, 6842.
34. (b) Shen, Z.; Strauss, J.; Daub, J. Chem. Commun. 2002, 460.
35. (c) Koenig, B.; Pelka, M.; Zieg, H.; Ritter, T.; Bouas-Laurent, H.; Bonneau, R.; Desvergne, J.-P. J. Am. Chem. Soc. 1999, 121, 1681.
36. (a) Fungo, F.: Samson, A.; Bard, A. J. Chem. Mater. 2003, 15, 1264.
37. (b) Ehmann, A.; Gompper, R.; Hartmann, H.: Mueller, T. J. J.; Polborn, K.; Schuetz, R. Angew. Chem., Int. Ed. Engl. 1994, 33, 572.
38. (c) Margerum, L. D.; Murray, R. W.; Meyer, T. J. J. Phys. Chem. A 1986, 90, 728.
39. Kowert, B. A.; Marcoux, B. A.; Bard, A. J. J. Am. Chem. Soc. 1972, 94, 5538.
40. (a) Bell, F. A.; Ledwith, A.; Sherrington, D. C. J. Chem. Soc. C 1969, 2719.
41. (b) Connelly, N. G.; Geiger, W. E. Chem. Rev. 1996, 96, 877.
42. .+ in the ET and self-association processes.
43. (a) Shine, H. J.; Mach, E. E. J. Org. Chem. 1965, 30, 2130.
44. (b) Wagner, E.; Filipek, S.; Kalinowski M. K. Monatsh. Chem. 1988, 119, 929.
45. Lu, J.-M.; Chen, Y.; Wen, X.; Wu, L.-M.; Jia, X.; Liu, Y. C.; Liu, Z.-L. J. Phys. Chem. A 1999, 103, 6998.
46. Note that in this study, dichloromethane was the solvent of choice because of the expanded temperature range accessible for the kinetic studies as well as the enhanced solubility and stability of the various phenothiazine cation radical salts examined in this study.
47. .+, respectively, by Bard et al.14
48. For previous examples of intermolecular π-association of various cation radicals, see: (a) Lewis, L. C.; Singer, L. S. Chem. Phys. 1965, 43, 2712.
49. (b) Howarth, O. W.; Fraenkel, G. K. J. Am. Chem. Soc. 1966, 88, 4514.
50. (c) Howarth, O. W.; Fraenkel, G. K. J. Chem. Phys. 1970, 52, 6258.
51. (d) Badger, B.; Brocklehurst, B. Nature 1968, 219, 263.
52. (e) Badger, B.; Brocklehurst, B.; Dudley, R. Chem. Phys. Lett. 1967, 1, 122.
53. (f) Badger, B.; Brocklehurst, B. Trans. Faraday Soc. 1969, 65, 2582.
54. (g) Badger, B.; Brocklehurst, B. Trans. Faraday Soc. 1969, 65, 2588.
55. (h) Badger, B.; Brocklehurst, B. Trans. Faraday Soc. 1970, 66, 2939.
56. (i) Meot-Ner, M.; Hamlet, P.; Hunter, E. P.; Field, F. H. J. Am. Chem. Soc. 1978, 100, 5466.
57. (j) Meot-Ner, M. J. Phys. Chem. 1980, 84, 2724.
58. (k) Meot-Ner, M.; El-Shall, M. S. J. Am. Chem. Soc. 1986, 108, 4386.
59. (l) All attempts to prepare the corresponding anionic dimers in solution have been unsuccessful heretofore.
60. 2+ complexes23).
61. For the spectral and structural characterization of such cation radical "π-mers", see: (a) Le Magueres, P.; Lindeman, S.; Kochi, J. K. J. Chem. Soc., Perkin Trans 2, 2001, 1180.
62. (b) Kochi, J. K.; Rathore, R.; Le Magueres, P. J. Org. Chem. 2000, 65, 6826 and references therein.
63. (c) Charge resonance as employed here derives from Badger, Brocklehurst et al.21d-g to describe the NIR absorption bands associated with the transient cationic pimers of various aromatic donors.
64. 2+ at low temperature, see Figure S6.
65. Benesi, H. A.; Hildebrand, J. H. J. Am. Chem. Soc. 1949, 71, 2703.
66. Lü, J.-M.; Rosokha, S. V.; Kochi, J. K. J. Am. Chem. Soc. 2003, 125, 12161.
67. (a) McDowell, J. J. H. Acta Crystallogr., Sect. B 1976, 32, 5.
68. (b) Uchida, T.; Ito, M.; Kozawa, K. Bull. Chem. Soc. Jpn. 1983, 56, 577.
69. For other comparative studies of 2:1 and 1:1 pimeric structures, see: (a) Le Magueres, P.; Lindeman, S. V.: Kochi, J. K. Org. Lett. 2000, 2, 3567.
70. (b) We conclude from the bond distance changes and the opening of the dihedral angle α that the effective charge on the central phenothiazine in the triplex is roughly +1.0 and the asymmetric distribution is +0.7 and +0.3 on the terminal phenothiazines (see Table 2, entries 3-5).
71. (a) Note that the strong similarity of the solid-state spectrum in Figure S5 and the NIR band of the precursor complex in solution (Figure 1) supports such a suggestion.
72. (b) The 3.3 Å separation is similar to those published previously for different complexes between cation and anion radicals and their neutral precursor (e.g., in the 1:1 pimer of octamethylanthracene, which is isoelectronic with phenothiazine).26b The planar moieties within such associates lie atop one another (or somewhat shifted) with the interplanar separation of 3.3 ± 0.3 Å which does not essentially depend on the stoichiometric composition of the particular complex (1:1, 1:2, 2:1, etc).41
73. (c) In the [1:1] charge-transfer complexes between phenothiazine and 7,7,8,8-tetracyanoquinedimethane28d or 1,3,5-trinitrobenzene,28e the donor and acceptor moieties also lie atop each other at the interplanar distance of about 3.4 Å.
74. (d) Toupet, L.; Carl, N. Acta Crystallogr., C 1995, 51, 249.
75. (e) Fritchie, C. J., Jr. J. Chem. Soc. A 1969, 1328.
76. (a) Creutz, C. Prog. Inorg. Chem. 1983, 30, 1.
77. (b) Evans, C. E. B.; Naklicki, M. L.; Rezvani, A. R.; White, C. A.; Kondratiev, V. V.; Crutchley, R. J. J. Am. Chem. Soc. 1998, 120, 13096.
78. (a) Lindeman, S. V.; Rosokha; S. V.; Sun, D.-L.; Kochi, J. K. J. Am. Chem. Soc. 2002, 124, 843.
79. (b) Rosokha S. V.; Sun, D.-L.; Kochi, J. K. J. Phys. Chem. A 2002, 106, 2283.
80. See also Table 6, column 7.
81. (a) Heinzer, J. Quantum Chemistry Program Exchange 209, as modified by Petillo, P. A. and Ismagilov, R. F. We thank Prof. S. F. Nelsen for providing us with a copy of this program.
82. -1) at which the diagnostic alternating line width effects would be observed in the dynamic simulation of the ESR spectra, as we previously showed in a related mixed-valence system.36 We thank a reviewer for pointing out the desirability for such an experimental verification.
83. (a) Gerson, F.; Kaupp, G.; Ohya-Nishiguchi, H. Angew. Chem., Int. Ed. Engl. 1977, 16, 657.
84. (b) Wartin, A. R.; Valenzuela, J.; Staab, H. A.; Neugebauer, F. A. Eur. J. Org. Chem. 1998, 139, 9.
85. (c) Lau, W.; Kochi, J. K. J. Org. Chem. 1986, 51, 1801.
86. 2+ as a triplet (ground-state) dication diradical (or as a nearly degenerate singlet/triplet ground state).34b
87. (b) Okada, K.; Imakura, T.; Oda, M.; Murai, H. J. Am. Chem. Soc. 1996, 118, 3047.
88. .+/P redox centers.
89. (b) For a discussion of this crystallographic point as it applies to a related aromatic redox center, see Le Magueres, P. et al. in ref 22a and Lindeman et al. in ref 30a.
90. Sun, D.-L.; Rosokha, S. V.; Lindeman, S. V.: Kochi, J. K. J. Am. Chem. Soc. 2003, 125, 15950.
91. Ganesan, V.; Rosokha, S. V.; Kochi, J. K. J. Am. Chem. Soc. 2003, 125, 2559.
92. For the detailed description of intermolecular ET kinetics, see the following discussion.
93. (a) Mulliken, R. S. J. Am. Chem. Soc. 1952, 74, 811.
94. (b) Mulliken, R. S. J. Phys. Chem. 1952, 56, 801.
95. (c) Mulliken, R. S.; Person, W. B. Molecular Complexes; Wiley: New York, 1969.
96. (a) Hush, N. S. Z. Electrochem. 1957, 61, 734.
97. (b) Hush, N. S. Trans. Faraday Soc. 1961, 57, 557.
98. (c) Hush, N. S. Prog. Inorg. Chem. 1967, 8, 391.
99. (d) Hush, N. S. Electrochim. Acta 1968, 13, 1005.
100. D in [2:1] complexes is close to that in the corresponding [1:1] associationS.41c.d
101. .+ is close to that based on X-ray studies
102. (c) Hanson, A. W. Acta Crystallogr. 1968, B24, 773.
103. (d) Fritchie, C. J.; Arthur, P., Jr. Acta Crystallogr. 1966, 21, 139.
104. (e) See also: Nelsen, S. F.; Newton, M. D. J. Phys. Chem. 2000, 104, 10023.
105. The two-state model for ET is based on orthogonal initial and final diabatic states. The extent to which there is orbital overlap between cofacial redox centers violates this restriction, but only strictly speaking. What is not yet known is the degree to which even a modicum of orbital overlap completely violates the applicability of the two-state model, and it thus remains to be seen (by further studies such as this) as to how far this restriction can be further tested with other (orbital) combinations.
106. (a) Nelsen, S. F.; Adamus, J.; Wolff, J. J. J. Am. Chem. Soc. 1994, 116, 1589.
107. (b) Nelsen, S. F.; Trieber, D. A.: Wolff, J. J.; Powell, D. R.; Rogers-Crowley, S. J. Am. Chem. Soc. 1997, 119, 6873.
108. (c) Nelsen, S. F.; Ramm, M. T.; Wolff, J. J.; Powell, D. R. J. Am. Chem. Soc. 1997, 119, 6863.
109. (d) Nelsen, S. F.; Ismagilov, R. F.; Powell, D. R. J. Am. Chem. Soc. 1997, 119, 10213.
110. (a) Lambert, C.; Noll, G. J. Am. Chem. Soc. 1999, 121, 8434.
111. (b) Holzapfel, M.; Lambert, C.; Selinka, C.; Stalke, D. J. Chem. Soc., Perkin Trans. 2 2002, 1553.
112. 2+ as determined by Okada et al.34b from its ESR (triplet) spectrum.
113. AD < λ/2 in Table 6 support the assignment of these systems to Class II.
114. (b) Robin, M. B.; Day, P. Adv. Inorg. Chem. Radiochem. 1967, 10, 247.
115. For such a syn conformation in the analogous o-xylylene-bridged cation radical with benzenoid redox centers, see Sun, D.-L. et al. in ref 36.
116. 2+ systematically change from tub/tub, tub/planar, and planar/ planar, respectively. See text for the mechanistic implications of such structural changes in the phenothiazine redox centers.
117. Compare with the ORTEP structure in Figure S10.
118. -9 s, we tentatively conclude that it falls into the Robin-Day Class II category based on the solvent dependence of the intervalence band as seen by the blue-shift with increasing solvent polarity as described in Table S1.
119. -1 is not uncommon (see: Elliot et al. in ref 54).
120. -1), and the reorganization energy would be less (not greater) than the maximum values listed in Tables 5 and 6.
121. Note that HTD evaluated from the electrochemical data is expected to represent an upper limit to the intrinsic electronic coupling element because of the neglect of the other energy terms.36,52
122. ab is generally weaker for the organic intervalence compounds with aromatic redox centers (due to small solvation difference between dication and cation) than for the usual mixed-valence coordination compounds.
123. .+ may necessitate some correction of the parameters obtained via eq 8.
124. For previous examples of the application of such a test, see: Elliot, C. M.; Derr, D. L.; Matyushov, D. V.; Newton, M. D. J. Am. Chem. Soc. 1998, 120, 11714, and Nelsen and co-workers in ref 43.
125. -1, the same value as previously used for the description of ET in phenylene-bridged organic mixed-valence cation radicals30 and in the kinetics evaluation of the intermolecular anion radical self-exchange.37
126. .+/PH) self-exchange underscores its utilitarian value for further use provided that due cognizance is presently taken of the rigorous definitions of the separation parameter and the pre-exponential factor for reliable computations of the Mulliken-Hush electronic coupling element.
127. Grampp, G.; Jaenicke, W. Ber. Bunsen-Ges. Phys. Chem. 1991, 95, 904.
128. ET‡(theor) = 2.5 kcal/ mol. Note, however, that such a close coincidence may be somewhat fortuitous, since the accurate comparison requires the more rigorous estimate of diffusion effects.
129. (b) Calvert, J. G.; Pitts, J. N., Jr. Photochemistry; Wiley: New York, 1966; p 627.
130. 2). Thus, it cannot be applied quantitatively to the pimer in which two phenothiazine moieties are positioned parallel at an interplanax separation less than their molecular size. As a result, the pimer is best considered as a dipole within the solvent sphere, and the redox process within such a pimer will require substantially less solvent reorganization.
131. -1 and λ = 17 kcal/mol.
132. (b) The planarization of both phenothiazine redox centers in the pimer indicates that part of the reorganization energy is already taken up in the pre-equilibrium step prior to the electron-transfer step. Compare with: Gwaltney, S. R.; Rosokha, S. V.; Head-Gordon, M.; Kochi, J. K. J. Am. Chem. Soc. 2003, 125, 3273.
133. Perrin, D. D.; Armarego, W. L. F.; Perrin, D. R. Purification of Laboratory Chemicals, 2nd ed.; Pergamon: New York, 1980.
134. Hart, H.; Harada, K.; Du, C.-J. F. J. Org. Chem. 1985, 50, 3104.
135. Závada, J.; Pánková, M.; Aenold, Z. Collect. Czech. Chem. Commun. 1976, 41, 1777.
136. Kim, E. K.; Kochi, J. K. J. Am. Chem. Soc. 1991, 113, 4962.
137. Clarke, D.; Gilbert, B. C.; Hanson, P.; Kirk, C. M. J. Chem. Soc., Perkin Trans. 2 1978, 10, 1103 and references therein.
138. Okada, K.; Imakura, T.; Oda, M.; Murai, H. J. Am. Chem. Soc. 1996, 118, 3047.
139. Rathore, R.; Kumar, A. S.; Lindeman, S. V.; Kochi, J. K. J. Org. Chem. 1998, 63, 5847.
140. Sheldrick, G. M. SHELXS-86, Program for Structure Solution; University of Göttingen: Göttingen, Germany, 1986.