Mechanistic crossover induced by steric hindrance: A theoretical study of electron transfer and substitution mechanisms of cyanoformaldehyde anion radical and alkyl halides

Journal of the American Chemical Society

Volumn 120, Issue 9, 1998, Pages 2131-2145

  Sastry, G Narahari ^a,b   Shaik, Sason ^c  

^a UNIVERSITY OF FRIBOURG   (Switzerland)

^b PONDICHERRY UNIVERSITY   (India)

^c HEBREW UNIVERSITY OF JERUSALEM   (Israel)

Author keywords

[No Author keywords available]

Indexed keywords

ANION; CYANOFORMALDEHYDE; FORMALDEHYDE; HALIDE; RADICAL; UNCLASSIFIED DRUG;

ALKYLATION; ARTICLE; CHEMICAL BINDING; ELECTRON TRANSPORT; ENERGY; REACTION ANALYSIS; STEREOSPECIFICITY;

EID: 0032507277     PISSN: 00027863     EISSN: None     Source Type: Journal    
DOI: 10.1021/ja972746b     Document Type: Article

References (93)

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5. For general references, see: (a) Eberson, L. Electron-Transfer Reactions in Organic Chemistry; Springer-Verlag: Heidelberg, 1987. (b) Savéant, J.-M. Adv. Phys. Org. Chem. 1990, 26, 1. (c) Lund, H.; Daasberg, K.; Lund, T.; Pedersen, S. U. Acc. Chem. Res. 1995, 28, 8, 313 (d) Spieser, B. Angew. Chem., Int. Ed. Engl. 1996, 35, 2471. (e) Zipse, H. Angew. Chem., Int. Ed. Engl. 1997, 36, 1697.
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12. For experimental strategies and mechanistic criteria in anion radical chemistry, see: (a) Daasberg, K.; Pedersen, S. U.; Lund, H. Acta Chem. Scand. 1991, 45, 424. (b) Lund, T.; Lund, H. Acta Chem. Scand. 1986, B40, 470; 1987, B41, 93; 1988, B42, 269. (c) Daasberg, K.; Christensen, T. B. H. Acta Chem. Scand. 1995, 49, 128. (d) Lexa, D.; Savéant, J.-M.; Su, K.-B.; Wang, D.-L. J. Am. Chem. Soc. 1988, 110, 7617. (e) Saveant, J.-M. J. Am. Chem. Soc. 1988, 110, 7617. (f) Daasberg, K.; Hansen, J. H.; Lund, H. Acta Chem. Scand. 1990, 44, 711. (g) Daasberg, K.; Lund, H. Acta Chem. Scand. 1996, 50, 299.
13. For experimental strategies and mechanistic criteria in anion radical chemistry, see: (a) Daasberg, K.; Pedersen, S. U.; Lund, H. Acta Chem. Scand. 1991, 45, 424. (b) Lund, T.; Lund, H. Acta Chem. Scand. 1986, B40, 470; 1987, B41, 93; 1988, B42, 269. (c) Daasberg, K.; Christensen, T. B. H. Acta Chem. Scand. 1995, 49, 128. (d) Lexa, D.; Savéant, J.-M.; Su, K.-B.; Wang, D.-L. J. Am. Chem. Soc. 1988, 110, 7617. (e) Saveant, J.-M. J. Am. Chem. Soc. 1988, 110, 7617. (f) Daasberg, K.; Hansen, J. H.; Lund, H. Acta Chem. Scand. 1990, 44, 711. (g) Daasberg, K.; Lund, H. Acta Chem. Scand. 1996, 50, 299.
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15. For experimental strategies and mechanistic criteria in anion radical chemistry, see: (a) Daasberg, K.; Pedersen, S. U.; Lund, H. Acta Chem. Scand. 1991, 45, 424. (b) Lund, T.; Lund, H. Acta Chem. Scand. 1986, B40, 470; 1987, B41, 93; 1988, B42, 269. (c) Daasberg, K.; Christensen, T. B. H. Acta Chem. Scand. 1995, 49, 128. (d) Lexa, D.; Savéant, J.-M.; Su, K.-B.; Wang, D.-L. J. Am. Chem. Soc. 1988, 110, 7617. (e) Saveant, J.-M. J. Am. Chem. Soc. 1988, 110, 7617. (f) Daasberg, K.; Hansen, J. H.; Lund, H. Acta Chem. Scand. 1990, 44, 711. (g) Daasberg, K.; Lund, H. Acta Chem. Scand. 1996, 50, 299.
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17. For experimental strategies and mechanistic criteria in anion radical chemistry, see: (a) Daasberg, K.; Pedersen, S. U.; Lund, H. Acta Chem. Scand. 1991, 45, 424. (b) Lund, T.; Lund, H. Acta Chem. Scand. 1986, B40, 470; 1987, B41, 93; 1988, B42, 269. (c) Daasberg, K.; Christensen, T. B. H. Acta Chem. Scand. 1995, 49, 128. (d) Lexa, D.; Savéant, J.-M.; Su, K.-B.; Wang, D.-L. J. Am. Chem. Soc. 1988, 110, 7617. (e) Saveant, J.-M. J. Am. Chem. Soc. 1988, 110, 7617. (f) Daasberg, K.; Hansen, J. H.; Lund, H. Acta Chem. Scand. 1990, 44, 711. (g) Daasberg, K.; Lund, H. Acta Chem. Scand. 1996, 50, 299.
18. For experimental strategies and mechanistic criteria in anion radical chemistry, see: (a) Daasberg, K.; Pedersen, S. U.; Lund, H. Acta Chem. Scand. 1991, 45, 424. (b) Lund, T.; Lund, H. Acta Chem. Scand. 1986, B40, 470; 1987, B41, 93; 1988, B42, 269. (c) Daasberg, K.; Christensen, T. B. H. Acta Chem. Scand. 1995, 49, 128. (d) Lexa, D.; Savéant, J.-M.; Su, K.-B.; Wang, D.-L. J. Am. Chem. Soc. 1988, 110, 7617. (e) Saveant, J.-M. J. Am. Chem. Soc. 1988, 110, 7617. (f) Daasberg, K.; Hansen, J. H.; Lund, H. Acta Chem. Scand. 1990, 44, 711. (g) Daasberg, K.; Lund, H. Acta Chem. Scand. 1996, 50, 299.
19. For experimental strategies and mechanistic criteria in anion radical chemistry, see: (a) Daasberg, K.; Pedersen, S. U.; Lund, H. Acta Chem. Scand. 1991, 45, 424. (b) Lund, T.; Lund, H. Acta Chem. Scand. 1986, B40, 470; 1987, B41, 93; 1988, B42, 269. (c) Daasberg, K.; Christensen, T. B. H. Acta Chem. Scand. 1995, 49, 128. (d) Lexa, D.; Savéant, J.-M.; Su, K.-B.; Wang, D.-L. J. Am. Chem. Soc. 1988, 110, 7617. (e) Saveant, J.-M. J. Am. Chem. Soc. 1988, 110, 7617. (f) Daasberg, K.; Hansen, J. H.; Lund, H. Acta Chem. Scand. 1990, 44, 711. (g) Daasberg, K.; Lund, H. Acta Chem. Scand. 1996, 50, 299.
20. For experimental strategies and mechanistic criteria in anion radical chemistry, see: (a) Daasberg, K.; Pedersen, S. U.; Lund, H. Acta Chem. Scand. 1991, 45, 424. (b) Lund, T.; Lund, H. Acta Chem. Scand. 1986, B40, 470; 1987, B41, 93; 1988, B42, 269. (c) Daasberg, K.; Christensen, T. B. H. Acta Chem. Scand. 1995, 49, 128. (d) Lexa, D.; Savéant, J.-M.; Su, K.-B.; Wang, D.-L. J. Am. Chem. Soc. 1988, 110, 7617. (e) Saveant, J.-M. J. Am. Chem. Soc. 1988, 110, 7617. (f) Daasberg, K.; Hansen, J. H.; Lund, H. Acta Chem. Scand. 1990, 44, 711. (g) Daasberg, K.; Lund, H. Acta Chem. Scand. 1996, 50, 299.
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59. For ET in systems with an even number of electrons, the ET-TS's appear to resemble nonbonded outer-sphere situations. See: (a) Shaik, S. S. Acta Chem. Scand. 1990, 44, 205. Apeloig, Y.; Aharoni, O. M.; Danovich, D.; Ioffe, A.; Shaik, S. Isr. J. Chem. 1993, 33, 387.
60. For ET in systems with an even number of electrons, the ET-TS's appear to resemble nonbonded outer-sphere situations. See: (a) Shaik, S. S. Acta Chem. Scand. 1990, 44, 205. Apeloig, Y.; Aharoni, O. M.; Danovich, D.; Ioffe, A.; Shaik, S. Isr. J. Chem. 1993, 33, 387.
61. •+ systems, see: (a) Reference 20. (b) Shaik, S.; Reddy, A. C.; Ioffe, A.; Dinnocenzo, J. P.; Danovich, D.; Cho, J. K. J. Am. Chem. Soc. 1995, 117, 3205. Note how the charge and spin density analysis leads to the conclusion that the ET-TS possesses a SUB character and vice versa, SUB-TS possesses some ET character.
62. •+ systems, see: (a) Reference 20. (b) Shaik, S.; Reddy, A. C.; Ioffe, A.; Dinnocenzo, J. P.; Danovich, D.; Cho, J. K. J. Am. Chem. Soc. 1995, 117, 3205. Note how the charge and spin density analysis leads to the conclusion that the ET-TS possesses a SUB character and vice versa, SUB-TS possesses some ET character.
63. ET crossing will be established first and leads to an ET-TS. See ref 11.
64. R curve represents the bond as a Lewis bond, which involves the covalent and ionic structure mixed.
65. Shaik, S. S. Prog. Phys. Org. Chem. 1985, 15, 195. Pross, A. Adv. Phys. Org. Chem. 1985, 21, 99.
66. Shaik, S. S. Prog. Phys. Org. Chem. 1985, 15, 195. Pross, A. Adv. Phys. Org. Chem. 1985, 21, 99.
67. For example: (a) ref 2a page 125 and Chapter XI. (b) Bakac, A.; Espenson, J. H., J. Am. Chem. Soc. 1986, 108, 713; 719. (c) Bank, S.; Noyd, D. A. J. Am. Chem. Soc. 1973, 95, 8203. (d) Perrin, C. L. J. Phys. Chem., 1984, 88, 3611 (e) Lund, T.; Lund, H., Tetrahedron Lett. 1986, 27, 95. (f) Fukuzumi, S.; Kochi, J. K., J. Am. Chem. Soc. 1981, 103, 7240, 7599. (g) Bethell, D.; Clar, P. N.; Hare, G. J. J. Chem. Soc., Perkin Trans. 2 1983, 1889. (h) Chanon, M. Bull. Chim. Soc. Fr. 1982, Part II, 197. (i) Tolbert, L. M.; Bedleck, J.; Terapare, M.; Kowalik, J. J. Am. Chem. Soc. 1997, 119, 2291.
68. For example: (a) ref 2a page 125 and Chapter XI. (b) Bakac, A.; Espenson, J. H., J. Am. Chem. Soc. 1986, 108, 713; 719. (c) Bank, S.; Noyd, D. A. J. Am. Chem. Soc. 1973, 95, 8203. (d) Perrin, C. L. J. Phys. Chem., 1984, 88, 3611 (e) Lund, T.; Lund, H., Tetrahedron Lett. 1986, 27, 95. (f) Fukuzumi, S.; Kochi, J. K., J. Am. Chem. Soc. 1981, 103, 7240, 7599. (g) Bethell, D.; Clar, P. N.; Hare, G. J. J. Chem. Soc., Perkin Trans. 2 1983, 1889. (h) Chanon, M. Bull. Chim. Soc. Fr. 1982, Part II, 197. (i) Tolbert, L. M.; Bedleck, J.; Terapare, M.; Kowalik, J. J. Am. Chem. Soc. 1997, 119, 2291.
69. For example: (a) ref 2a page 125 and Chapter XI. (b) Bakac, A.; Espenson, J. H., J. Am. Chem. Soc. 1986, 108, 713; 719. (c) Bank, S.; Noyd, D. A. J. Am. Chem. Soc. 1973, 95, 8203. (d) Perrin, C. L. J. Phys. Chem., 1984, 88, 3611 (e) Lund, T.; Lund, H., Tetrahedron Lett. 1986, 27, 95. (f) Fukuzumi, S.; Kochi, J. K., J. Am. Chem. Soc. 1981, 103, 7240, 7599. (g) Bethell, D.; Clar, P. N.; Hare, G. J. J. Chem. Soc., Perkin Trans. 2 1983, 1889. (h) Chanon, M. Bull. Chim. Soc. Fr. 1982, Part II, 197. (i) Tolbert, L. M.; Bedleck, J.; Terapare, M.; Kowalik, J. J. Am. Chem. Soc. 1997, 119, 2291.
70. For example: (a) ref 2a page 125 and Chapter XI. (b) Bakac, A.; Espenson, J. H., J. Am. Chem. Soc. 1986, 108, 713; 719. (c) Bank, S.; Noyd, D. A. J. Am. Chem. Soc. 1973, 95, 8203. (d) Perrin, C. L. J. Phys. Chem., 1984, 88, 3611 (e) Lund, T.; Lund, H., Tetrahedron Lett. 1986, 27, 95. (f) Fukuzumi, S.; Kochi, J. K., J. Am. Chem. Soc. 1981, 103, 7240, 7599. (g) Bethell, D.; Clar, P. N.; Hare, G. J. J. Chem. Soc., Perkin Trans. 2 1983, 1889. (h) Chanon, M. Bull. Chim. Soc. Fr. 1982, Part II, 197. (i) Tolbert, L. M.; Bedleck, J.; Terapare, M.; Kowalik, J. J. Am. Chem. Soc. 1997, 119, 2291.
71. For example: (a) ref 2a page 125 and Chapter XI. (b) Bakac, A.; Espenson, J. H., J. Am. Chem. Soc. 1986, 108, 713; 719. (c) Bank, S.; Noyd, D. A. J. Am. Chem. Soc. 1973, 95, 8203. (d) Perrin, C. L. J. Phys. Chem., 1984, 88, 3611 (e) Lund, T.; Lund, H., Tetrahedron Lett. 1986, 27, 95. (f) Fukuzumi, S.; Kochi, J. K., J. Am. Chem. Soc. 1981, 103, 7240, 7599. (g) Bethell, D.; Clar, P. N.; Hare, G. J. J. Chem. Soc., Perkin Trans. 2 1983, 1889. (h) Chanon, M. Bull. Chim. Soc. Fr. 1982, Part II, 197. (i) Tolbert, L. M.; Bedleck, J.; Terapare, M.; Kowalik, J. J. Am. Chem. Soc. 1997, 119, 2291.
72. For example: (a) ref 2a page 125 and Chapter XI. (b) Bakac, A.; Espenson, J. H., J. Am. Chem. Soc. 1986, 108, 713; 719. (c) Bank, S.; Noyd, D. A. J. Am. Chem. Soc. 1973, 95, 8203. (d) Perrin, C. L. J. Phys. Chem., 1984, 88, 3611 (e) Lund, T.; Lund, H., Tetrahedron Lett. 1986, 27, 95. (f) Fukuzumi, S.; Kochi, J. K., J. Am. Chem. Soc. 1981, 103, 7240, 7599. (g) Bethell, D.; Clar, P. N.; Hare, G. J. J. Chem. Soc., Perkin Trans. 2 1983, 1889. (h) Chanon, M. Bull. Chim. Soc. Fr. 1982, Part II, 197. (i) Tolbert, L. M.; Bedleck, J.; Terapare, M.; Kowalik, J. J. Am. Chem. Soc. 1997, 119, 2291.
73. For example: (a) ref 2a page 125 and Chapter XI. (b) Bakac, A.; Espenson, J. H., J. Am. Chem. Soc. 1986, 108, 713; 719. (c) Bank, S.; Noyd, D. A. J. Am. Chem. Soc. 1973, 95, 8203. (d) Perrin, C. L. J. Phys. Chem., 1984, 88, 3611 (e) Lund, T.; Lund, H., Tetrahedron Lett. 1986, 27, 95. (f) Fukuzumi, S.; Kochi, J. K., J. Am. Chem. Soc. 1981, 103, 7240, 7599. (g) Bethell, D.; Clar, P. N.; Hare, G. J. J. Chem. Soc., Perkin Trans. 2 1983, 1889. (h) Chanon, M. Bull. Chim. Soc. Fr. 1982, Part II, 197. (i) Tolbert, L. M.; Bedleck, J.; Terapare, M.; Kowalik, J. J. Am. Chem. Soc. 1997, 119, 2291.
74. For example: (a) ref 2a page 125 and Chapter XI. (b) Bakac, A.; Espenson, J. H., J. Am. Chem. Soc. 1986, 108, 713; 719. (c) Bank, S.; Noyd, D. A. J. Am. Chem. Soc. 1973, 95, 8203. (d) Perrin, C. L. J. Phys. Chem., 1984, 88, 3611 (e) Lund, T.; Lund, H., Tetrahedron Lett. 1986, 27, 95. (f) Fukuzumi, S.; Kochi, J. K., J. Am. Chem. Soc. 1981, 103, 7240, 7599. (g) Bethell, D.; Clar, P. N.; Hare, G. J. J. Chem. Soc., Perkin Trans. 2 1983, 1889. (h) Chanon, M. Bull. Chim. Soc. Fr. 1982, Part II, 197. (i) Tolbert, L. M.; Bedleck, J.; Terapare, M.; Kowalik, J. J. Am. Chem. Soc. 1997, 119, 2291.
75. For example: (a) ref 2a page 125 and Chapter XI. (b) Bakac, A.; Espenson, J. H., J. Am. Chem. Soc. 1986, 108, 713; 719. (c) Bank, S.; Noyd, D. A. J. Am. Chem. Soc. 1973, 95, 8203. (d) Perrin, C. L. J. Phys. Chem., 1984, 88, 3611 (e) Lund, T.; Lund, H., Tetrahedron Lett. 1986, 27, 95. (f) Fukuzumi, S.; Kochi, J. K., J. Am. Chem. Soc. 1981, 103, 7240, 7599. (g) Bethell, D.; Clar, P. N.; Hare, G. J. J. Chem. Soc., Perkin Trans. 2 1983, 1889. (h) Chanon, M. Bull. Chim. Soc. Fr. 1982, Part II, 197. (i) Tolbert, L. M.; Bedleck, J.; Terapare, M.; Kowalik, J. J. Am. Chem. Soc. 1997, 119, 2291.
76. Rauhut, G.; Clark, T. J. Chem. Soc., Faraday Trans. 1994, 90, 1783.
77. Using a Wolfsberg-Helmholtz type approximation, B = KS (K = 8.8 eV.; S = overlap integral), the value for B is larger. See, e.g.; Plato, M.; Mobius, K.; Michel-Beyerle, M. E.; Bixon, M.; Jortner, J. J. Am. Chem. Soc. 1988, 110, 7279.
78. ET values, obtained in this study, we determined that f ≥ 0.33, while the f factor of the quadratic expressions is ∼0.25. The larger f of the VBCM equation is in line with the steric argument on the descent of the lines in Figure 5b. Further conclusions will await a detailed application.
79. N2 Mechanism; Wiley and Sons: New York, 1992, discussion of TS geometriy in Chapters 5 and 6.
80. N2 Mechanism; Wiley and Sons: New York, 1992, discussion of TS geometriy in Chapters 5 and 6.
81. N2 Mechanism; Wiley and Sons: New York, 1992, discussion of TS geometriy in Chapters 5 and 6.
82. N2 Mechanism; Wiley and Sons: New York, 1992, discussion of TS geometriy in Chapters 5 and 6.
83. N2 Mechanism; Wiley and Sons: New York, 1992, discussion of TS geometriy in Chapters 5 and 6.
84. N2 Mechanism; Wiley and Sons: New York, 1992, discussion of TS geometriy in Chapters 5 and 6.
85. N2 Mechanism; Wiley and Sons: New York, 1992, discussion of TS geometriy in Chapters 5 and 6.
86. N2 Mechanism; Wiley and Sons: New York, 1992, discussion of TS geometriy in Chapters 5 and 6.
87. N2 Mechanism; Wiley and Sons: New York, 1992, discussion of TS geometriy in Chapters 5 and 6.
88. N2 Mechanism; Wiley and Sons: New York, 1992, discussion of TS geometriy in Chapters 5 and 6.
89. N2 Mechanism; Wiley and Sons: New York, 1992, discussion of TS geometriy in Chapters 5 and 6.
90. N2 Mechanism; Wiley and Sons: New York, 1992, discussion of TS geometriy in Chapters 5 and 6.
91. N2 Mechanism; Wiley and Sons: New York, 1992, discussion of TS geometriy in Chapters 5 and 6.
92. N2 Mechanism; Wiley and Sons: New York, 1992, discussion of TS geometriy in Chapters 5 and 6.
93. ET crossing will generate an excited cyanoformaldehyde (nπ*).