Abstract
PCILO and ab initio calculations have been performed to investigate the energies associated to rotation about the central bond in n-butane and methyl ethyl ether. Quantum mechanical energies have been fit to a classical intramolecular force field, containing torsional and nonbonded (Lennard-Jones 6–12 plus Coulomb) contributions, with a standard deviation comprised between 0.03 and 0.09 kcal mol−1. Two conditions have proved indispensable to reach such level of accuracy: (a) the use of a torsional potential with threefold periodicity, which corrects for the part of the rotation barrier not covered by van der Waals repulsions and may be interpreted as bond-bond repulsion; (b) the introduction in the force field for ethers of terms accounting for orbital interaction effects of different nature than the normal molecular mechanics nonbonded interactions; these terms are represented either by low order rotational potential functions or preferably by interactions of atoms simulating lone-pair orbitals and bonded to oxygen in such a way as to render it sp 3-hybridized. According to ab initio, the height of the threefold torsional potential about C-C and C-O bonds is comparable and is of the order of 3 kcal mol−1. According to PCILO, it is larger for C-C (ca. 1.5 kcal mol−1) than for C-O (ca. 0.5 kcal mol−1).
Similar content being viewed by others
References
Fantucci, P. C., Tosi, C.: XVI National Congress of the Italian Association of Chemical Physics, Abano Terme (Padova), 1981, Abstracts of papers, p. 33
Pullman, B., Courriére, Ph.: Proc. Jerusalem Symposia Quantum Chem. Biochem., Vol. V (Eds. E. D. Bergmann and B. Pullman), Jerusalem Academic Press, Jerusalem, 1972, p. 547
Tosi, C., Sänger, W.: Chem. Phys. Letters, in press
Levitt, M.: personal communication
Bradford, W. F., Fitzwater, S., Bartell, L. S.: J. Mol. Struct. 38, 185 (1977)
Szasz, G. J., Sheppard, N., Rank, D. H.: J. Chem. Phys. 16, 704 (1948)
Schrumpf, G.: Angew. Chem. 94, 152 (1982); Angew. Chem. Int. Ed. 21, 146 (1982)
Hoyland, J. R.: J. Chem. Phys. 49, 2563 (1968)
Kuchitsu, K.: Bull. Chem. Soc. Jpn. 32, 748 (1959)
Radom, L., Pople, J. A.: J. Am. Chem. Soc. 92, 4786 (1970)
Giunchi, G., Barino, L.: Gazz. Chim. Ital. 110, 395 (1980)
Pitzer, K. S.: J. Chem. Phys. 8, 711 (1940)
Ito, K.: J. Am. Chem. Soc. 75, 2430 (1953)
Piercy, J. E., Rao, M. S. G.: J. Chem. Phys. 46, 3951 (1967)
Hilgenfeld, R., Saenger, W.: Topics Curr. Chem. 101, 1 (1982)
Jorgensen, W. L., Ibrahim, M.: J. Am. Chem. Soc. 103, 3976 (1981)
Oyanagi, K., Kuchitsu, K.: Bull. Chem. Soc. Jpn. 51, 2237 (1978)
Kitigawa, T., Kusaki, K., Miyazawa, T.: Bull. Chem. Soc. Jpn. 46, 3685 (1973)
Kitigawa, T., Ohno, K., Sugeta, H., Miyazawa, T.: Bull. Chem. Soc. Jpn. 45, 969 (1972)
Durig, J. R., Compton, D. A. C.: J. Chem. Phys. 69, 4713 (1977)
Tosi, C., Lipari, G.: Theoret. Chim. Acta 60, 41 (1981)
Allinger, N. L., Chung, D. Y.: J. Am. Chem. Soc. 98, 6798 (1976)
Burkert, U.: Tetrahedron 33, 2237 (1977)
Tvaroska, I., Bleha, T.: Biopolymers 18, 2537 (1979)
Burkert, U.: Tetrahedron 35, 1945 (1979)
Burkert, U.: J. Comput. Chem. 1, 285 (1980)
Platt, E., Robson, B., Hillier, I. H.: J. Theor. Biol. 88, 333 (1981)
Chandler, J. P.: QCPE Program No. 66, 1973
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Tosi, C., Hilgenfeld, R. Quantum calculation of the intrinsic torsional barrier of C-C and C-O bonds. Theoret. Chim. Acta 62, 29–38 (1982). https://doi.org/10.1007/BF00551051
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00551051