The INDO/1 semi-empirical method is used to analyze the hydroxylation of alkanes by models for the putative active species in cytochromes P–450. In the insertion of oxygen into the CH bond by a M—O complex there are four atoms of particular interest, the metal and oxygen atoms of the oxidant plus the C and H atom of the CH bond to be activated. With four atoms being studied (3N-6), 6 degrees of freedom need to be described and a nearly intractable computational problem results. Thus, two reaction coordinates (CHI and OAT) were developed in an attempt to describe alkane hydroxylation in a chemically meaningful way. CHI (CH insertion) is a measure of the extent to which the CH bond has been activated and transferred to the O atom. OAT (oxygen atom transfer) is a measure of the extent to which the CO bond in the alcohol product has formed. The models chosen for the present study are manganyl (MnO) and ferryl (FeO) porphyrin complexes. Experimental evidence for manganese prophyrin complexes shows that as the axial ligand is made a stronger donor the insertion of the O atom into the CH bond becomes less concerted. The INDO/1 method was used to calculate the points on the PES determined by the changes in OAT and CHI. The results point to the axial ligand modifying the pathway by changing the relative electro-/nucleophilicity of the oxygen atom.

Bibliography

1 C. L. Hill, Activation and Functionalization of Alkanes (Wiley, New York, 1989).
Google Scholar
2(a) P. R. Ortiz de Montellano, Cytochrome P-450 (Plenum, New York, 1986);
10.1007/978-1-4757-9939-2
Google Scholar
(b) K. Ruckpaul and H. Rein, Cytochrome P-450 (Verlag, Berlin, 1984).
Google Scholar
3 F. P. Guengrich and T. L. MacDonald, Acc. Chem. Res. 17, 9 (1984).
10.1021/ar00097a002
Web of Science® Google Scholar
4 J. H. Dawson, Science 240, 433 (1988).
10.1126/science.3358128
CAS PubMed Web of Science® Google Scholar
5 G. H. Loew, J. R. Collins, B. Luke, A. Waleh, and A. T. Pudzianowski, Enzyme 36, 54 (1986).
10.1159/000469278
CAS PubMed Web of Science® Google Scholar
6 J. T. Groves, T. E. Nemo, and R. S. Myers, J. Am. Chem. Soc. 101, 1032 (1979).
10.1021/ja00498a040
CAS Web of Science® Google Scholar
7 T. L. Poulos, B. C. Finzel, and A. J. Howard, Biochemistry 26, 5314 (1986).
10.1021/bi00366a049
Web of Science® Google Scholar
8 R. H. Holm, Chem. Rev. 87, 1401 (1987).
10.1021/cr00082a005
CAS Web of Science® Google Scholar
9 M. J. Nappa and C. A. Tolman, Inorg. Chem. 24, 4711 (1985).
10.1021/ic00220a056
CAS Web of Science® Google Scholar
10 C. L. Hill and B. C. Schardt, J. Am. Chem. Soc. 102, 6374 (1980).
10.1021/ja00540a049
CAS Web of Science® Google Scholar
11 C. L. Hill, J. A. Smegal, and T. J. Henley, J. Org. Chem. 48, 3277 (1983).
10.1021/jo00167a023
CAS Web of Science® Google Scholar
12 M. J. Nappa and R. J. McKinney, Inorg. Chem. 27, 3740 (1988).
10.1021/ic00294a014
CAS Web of Science® Google Scholar
13(a) O(³P) + R — CH₃ : A. T. Pudzianowski and G. H. Loew, J. Phys. Chem. 87, 1081 (1983);
10.1021/j100229a029
CAS Web of Science® Google Scholar
(b) O(³P) + CH₄ : S. P. Walch and T. H. Dunning, J. Chem. Phys. 72, 3221 (1980);
10.1063/1.439558
CAS Web of Science® Google Scholar
(c) O(³P) + CH₄: M. S. Gordon Abstracts of Papers, 199th National Meeting of the American Chemical Society, Boston, April, 1990, Paper: PHYS 282.
Google Scholar
14 O(³P) + various organics: A. T. Pudzianowski and G. H. Loew, Intern. J. Quantum Chem. 23, 1257 (1983).
10.1002/qua.560230415
CAS Web of Science® Google Scholar
15 J. T. Groves and D. V. Subramanian, J. Am. Chem. Soc. 106, 2177 (1984).
10.1021/ja00319a044
CAS Web of Science® Google Scholar
16 K. U. Ingold, Aldrichemica Acta 22, 69 (1989).
CAS Google Scholar
17 J. A. Pople and D. L. Beveridge, Approximate Molecular Orbital Theory (McGraw Hill, New York, 1970).
Google Scholar
18 A. D. Bacon and M. C. Zerner, Theor. Chim. Acta 53, 21 (1979).
10.1007/BF00547605
CAS Web of Science® Google Scholar
19 W. P. Anderson, T. R. Cundari, R. S. Drago, and M. C. Zerner, Inorg. Chem. 29, 1 (1990).
10.1021/ic00326a001
CAS Web of Science® Google Scholar
20 W. P. Anderson, T. R. Cundari, and M. C. Zerner, Intern. J. Quantum Chem.—accepted for publication.
Google Scholar
21(a) T. R. Cundari and R. S. Drago, Inorg. Chem. 29, 487 (1990);
10.1021/ic00328a030
CAS Web of Science® Google Scholar
(b) T. R. Cundari and R. S. Drago, Intern. J. Quantum Chem. 36, 77 (1989);
10.1002/qua.560360609
Web of Science® Google Scholar
(c) T. R. Cundari and R. S. Drago, Inorg. Chem. 29, 2303 (1990);
10.1021/ic00337a023
CAS Web of Science® Google Scholar
(d) T. R. Cundari and R. S. Drago, Intern. J. Quantum Chem., Proceedings of the 1989 Sanibel Symposium 23, 489 (1989);
CAS Google Scholar
(e) T. R. Cundari, R. S. Drago, and M. C. Zerner, Inorg. Chem. 27, 4239 (1988).
10.1021/ic00296a030
CAS Web of Science® Google Scholar
22 W. D. Edwards and M. C. Zerner, Theor. Chim. Acta 72, 347 (1987).
10.1007/BF01192227
CAS Web of Science® Google Scholar
23 J. T. Groves and T. E. Nemo, J. Am. Chem. Soc. 105, 6243 (1983).
10.1021/ja00358a009
CAS Web of Science® Google Scholar
24(a) W. M. Atkins and S. G. Sligar, J. Am. Chem. Soc. 111, 2715 (1989);
10.1021/ja00189a057
CAS Web of Science® Google Scholar
(b) A theoretical analysis of this problem using molecular mechanics has been reported. G. H. Loew and J. R. Collins, J. Biol. Chem. 263, 3164 (1988);
PubMed Web of Science® Google Scholar
The application of ab-initio and semi-empirical methods to describe the chemistry of transition metal complexes is given in M. C. Zerner and D. Salahub Computational Chemistry: The Challenge of d and f electrons (ACS, Washington, 1989).
Google Scholar
25 Many of the problems encountered in the use of ab-initio calculations for transition-metal systems are discussed in Quantum Chemistry: The Challenge of Transition Metals and Coordination Chemistry A. Veillard, Ed. (Reidel, Dordrecht, 1986).
Google Scholar
26 P. M. Champion, J. Am. Chem. Soc. 111, 3433 (1989).
10.1021/ja00191a053
CAS Web of Science® Google Scholar
27(a) G. A. Hamilton, Adv. Enzymol. 32, 55 (1969),
10.1002/9780470122778.ch3
CAS PubMed Web of Science® Google Scholar
(b) V. Ullrich Angew. Chem., Int. Ed. 11, 701 (1972);
10.1002/anie.197207011
Google Scholar
(c) D. T. Sawyer, H. C. Tung, and H. Sugimoto, J. Am. Chem. Soc. 110, 2465 (1988);
10.1021/ja00211a024
Web of Science® Google Scholar
(d) D. Dolphin, A. W. Addison, M. Cairns, R. K. Dinello, N. P. Farrell, B. R. James, D. R. Paulson, and C. Welborn, Intern. J. Quantum Chem. 16, 311 (1979).
10.1002/qua.560160213
CAS Web of Science® Google Scholar
28 G. A. Olah, G. K. S. Prakash, and J. Sommer, Superacids (Wiley, New York, 1985) p. 311.
Google Scholar
29 A. Dedieu, M. M. Rohmer, and A. Veillard, Adv. Quantum Chem. 16, 43 (1982).
10.1016/S0065-3276(08)60351-2
CAS Web of Science® Google Scholar
30 M. B. Hall and J. E. Newton, Inorg. Chem. 23, 4627 (1984).
10.1021/ic00194a043
Web of Science® Google Scholar
31 W. D. Edwards, B. Weiner, and M. C. Zerner, J. Phys. Chem. 92, 6188 (1989).
10.1021/j100333a006
Web of Science® Google Scholar
32 M. Schappacher and R. Weiss, Inorg. Chem. 26, 1189 (1987).
10.1021/ic00255a001
CAS Web of Science® Google Scholar
33 Interatomic Distances L. E. Sutton, Ed. (Chemical Society, London, 1958).
Google Scholar
34 K. Hatano, K. Anza, and Y. Iitaka, Bull. Chem. Soc. Jpn. 56, 422 (1983).
10.1246/bcsj.56.422
CAS Web of Science® Google Scholar