An AM1 MO study of bond dissociation energies in substituted benzene and toluene derivatives relative to the principle of maximum hardness

Tetrahedron

Volumn 54, Issue 51, 1998, Pages 15445-15456

  Bean, Gerritt P ^a  

^a UNIVERSITY OF COLORADO   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

BENZENE DERIVATIVE; TOLUENE DERIVATIVE;

ARTICLE; DISSOCIATION; ELECTRON TRANSPORT; HARDNESS; HEAT; PRIORITY JOURNAL;

EID: 0032542109     PISSN: 00404020     EISSN: None     Source Type: Journal    
DOI: 10.1016/S0040-4020(98)00973-9     Document Type: Article

References (35)

1. 1 (a) Chattaraj, P. K.; Cedillo, A.; Parr, R. G.; Arnett, E. M. J. Org. Chem., 1995, 60, 4707.
2. (b) Arnett, E. M.; Ludwig, R. T., J. Am. Chem. Soc. 1995, 117, 6627.
3. 2 Pearson, R. G., J. Am. Chem. Soc. 1963, 85, 3533, ibid., 1986, 108, 6109.
4. 2 Pearson, R. G., J. Am. Chem. Soc. 1963, 85, 3533, ibid., 1986, 108, 6109.
5. 3 (a) Pearson, R. G., Acc. Chem. Res. 1993, 26, 250.
6. (b) Parr, R. G.; Zhou, Z., ibid. 1993, 26, 256.
7. 4 (a) Brauman, J. I. "Frontiers of Free Radical Chemistry", W. A. Pryor, Ed., Academic Press, New York, 1980.
8. (b) Bordwell, F. G.; Bausch, M. J., J. Am. Chem. Soc. 1986, 108, 1979.
9. (c) Wayner, D. D. M.; Parker, V. D., Acc. Chem. Res. 1993, 26, 287.
10. 5 Parr, R. G; Pearson, R. G., J. Am. Chem. Soc. 1983, 105, 7512.
11. 6 Dewar, M. J. S.; Zoebisch, E. G; Healy, E. F. Stewart, J. J. P., J. Am. Chem. Soc. 1985, 107, 3092.
12. 7 (a) Boyd, R. J.; Glover, J. N. M.; Pincock, J. A; J. Am. Chem. Soc. 1989, 111, 5152,
13. (b) Boyd, S. L.; Boyd, R. J.; Bessonette, P. W.; Kerdraon, D. L.; Aucoin, N., T., ibid. 1995, 117, 8816.
14. 8 Pauling, L. The Nature of the Chemical Bond, 3rd Ed.; Cornell Univ. Press; Ithaca, NY, 1960.
15. 9 As was explained by Hehre, et al., "Hartree-Fock theory with any basis set gives poor results for direct calculation of energy of homolytic dissociation process..", and electron correlation is necessary. Hehre, W. J.; Radom, L.; Schleyer, P. v.R.; Pople, J. A. Ab Initio Molecular Orbital Theory; Wiley; New York, 1986, p 273.
16. 10 The AM1 heats of formation of the substituted toluenes and the benzyl cations and anions along with their HOMO-LUMO energies were available from a previous study of their proton and hydride ion affinities; Bean, G. P. J. Org. Chem., 1993, 58, 7336. For the m-HO and CHO compounds, the conformer with the lower energy was used.
17. 11 Stewart, J. J. P. QCPE no. 455, MOPAC, revision 6.
18. f than they have in the phenyl ions.
19. 13 Berkowitz, J.; Ellison, G. B.; Gutmann, D., J. Phys. Chem. 1994, 98, 2744.
20. 14 (a) Ochterski, J. W.; Petersson, G. A.; Wiberg, K. B., J. Am. Chem. Soc. 1995, 117, 11299.
21. (b) Ochterski, J. W.; Petersson, G. A.; Montgomery, J. A., J. Chem. Phys. 1996, 104, 2598.
22. (c) Gaussian 94, Revision C.2, Frisch, M. J.; Trucks, G. W.; Schlegel, H. B.; Gill, P. M. W.; Johnson, B. G.; Robb, M. A.; Cheeseman, J. R.; Keith, T.; Petersson, G. A.; Montgomery, J. A.; Raghavachari, J. A. K.; Al-Laham, M. A.; Zakrzewski, V. G.; Ortiz, J. V.; Foresman, J. B.; Cioslowski, J.; Stefanov, B. B.; Nanayakkara, A.; Challacombe, M.; Peng, C. Y.; Ayala, P. Y.; Chen, W.; Wong, M. W.; Andres, J. L.; Replogle, E. S.; Gomperts, R.; Martin, R. L.; Fox, D. J.; Binkley, J. S.; Defrees, D. J.; Baker, J.; Stewart, J. P.; Head-Gordon, M.; Gonzalez, C.; Pople, J. A., Gaussian, Inc., Pittsburgh PA, 1995.
23. (d) The heats of formation were corrected to 298 K.
24. 15 Ellison, G. B.; Davico, G. E.; Bierbaum, V. M.; DePuy, C. H. Int. J. Mass Spectrom. Ion Processes 1996, 156, 109.
25. a ′s of a series of alcohols and the HOMO energies, as calculated by the AM1 MO method, of their conjugate bases. Vlasov, V. M.; Koppel, I. A.; Burk, P.; Koppel, I., J. Phys. Org. Chem. 1995, 8, 364.
26. homo values than found for the toluenes. It has been suggested that electron-withdrawing groups at the para position of the phenols increase the BDE by delocalizing the lone pair on the oxygen atom in the neutral phenol. Conversely, electron-donating groups stabilize the phenoxy radicals by increasing the spin delocalization and thus decreasing the BDE. See Brinck, T.; Haeberlein, M.; Jonsson, M. J. Am. Chem. Soc. 1997, 119, 4239; and references therein.
27. 2 are 103.6, 88.9, 83.7, 90.7, 108.4 and 57.7 kcal/mol, respectively; reference 14a. The ordering compares well to that observed here; 90.6, 79.2, 78.5, 92.9, 103.0, and 42.8 kcal/mol.
28. + bonds in the conjugate acids of several amines from their proton affinities and adiabatic ionization potentials. These are higher than the corresponding bonds in the neutral amines. Liu, W-Z.; Bordwell, F. G., J. Org. Chem. 1996, 61, 4778.
29. 20 The experimental BDE for benzene is 113.5 ± 0.5 kcal/mol. Davico, G. E.; Bierbaum, V. M.; DePuy, C. H.; Ellison, G. B.; Squires, R. R., J. Am. Chem. Soc. 1995, 117, 2590.
30. 21 This difference results from the difference in the heats of formation of the benzyl and phenyl radicals, 81.6 and 53.0, Table 2.
31. f ′s for the radicals, is 3.2 ± 3.6 kcal/mol.
32. 23 The LUMO and HOMO energies of the Y species were also obtained from AM1 MO calculations. They parallel the HOMO and LUMO energies from the CBS-4 calculations (3-21G* level).
33. -. Sims, B. A.; Milne, P. H.; Griller, D.; Wayner, D. D. M., J. Am. Chem. Soc. 1990, 112, 6635.
34. homo values for the toluenes are random but within a range of less than 2 kcal/mol. Wu., Y-D.; Wong, C-L.; Chan, K. W. K.; Ji, G-Z.; Jiang, X-K., J. Org. Chem. 1996, 61, 746.
35. (b) Also see reference 4c and Suryan, M. M.; Stein, E. E. J. Phys. Chem. 1991, 83, 777.