Artículos de revistas
Spectroscopic And Theoretical Studies Of Some P-substituted α-ethylsulfonylacetophenones
Registro en:
Journal Of Molecular Structure: Theochem. , v. 677, n. 1-3, p. 199 - 209, 2004.
1661280
10.1016/j.theochem.2004.01.032
2-s2.0-2042447802
Autor
Olivato P.R.
Reis A.K.C.A.
Ruiz Filho R.
Zukerman-Schpector J.
Rittner R.
Dal Colle M.
Institución
Resumen
The preferred conformations of p-substituted α- ethylsulfonylacetophenones, Y-PhC(O)CH2SO2Et (Y=OMe 1, Me 2, H 3, F 4, Cl 5, Br 6, CN 7 and NO2 8) are determined by νCO IR analysis, HF/6-31G** computations (1, 3, 5, 7 and 8) and X-ray diffraction for 5 and 7. The match between IR frequencies and intensities of the carbonyl doublet components in carbon tetrachloride (first overtone) and the results of the calculations indicates that the lower frequency component corresponds to the more stable gauche (g) conformer, while the higher frequency component is related to the quasi-cis (q-c) one. The gauche conformer (g) (ca. 85%) prevails over the quasi-cis conformer (q-c) population, and the q-c/g population ratio increases on going from electron-attracting to electron-donating substituents, both in the gas phase and in solution. These trends are discussed in terms of O(SO2)δ-⋯C(CO)δ+ charge transfer (CT), O(CO)δ-⋯S(SO2)δ+ (Coulombic interaction), H[CH2(Et)]δ+⋯O(CO)δ-, H δ+(2′)(o-Ph)⋯O(CO)δ- and Hδ+(6′) (o-Ph)⋯O(SO2)δ- hydrogen bonds and electrostatic interactions, along with the πCO/σ C-S* and πCO*/σC-S orbital interactions, which stabilise the g rotamer. The stabilisation of the q-c rotamer through O(CO)δ-⋯S (SO2)δ+ (CT), Hδ+(2′) (o-Ph)⋯O(CO)δ- and H [CH2(Et)]δ+⋯O(CO)δ- hydrogen bond interactions is counterbalanced by O (CO)δ-⋯O(SO2)δ- electrostatic repulsion, which destabilises significantly this rotamer. The X-ray diffraction analyses show that 5 and 7, in the solid, adopt the cis (c′) conformation, which is stabilised through intermolecular hydrogen bonds involving the acidic α-methylene Hδ+(3A), H(3B) and m-phenyl Hδ+(5′)[m-Ph] hydrogen atoms and the Oδ-(6), Oδ-(7) sulfonyl and O δ-(1) carbonyl oxygen atoms. © 2004 Elsevier B.V. All rights reserved. 677 1-3 199 209 Lumbroso, H., Bertin, D.M., Olivato, P.R., Bonfada, E., Mondino, M.G., Hase, Y., (1989) J. Mol. Struct., 213, p. 115 Olivato, P.R., Mondino, M.G., (1991) Phosphorus Sulfur Silicon Relat. Elem., 59, p. 219 Olivato, P.R., Bonfada, E., Rittner, R., (1992) Magn. Reson. Chem., 30, p. 81 Distefano, G., Dal Colle, M., Bertolasi, V., Olivato, P.R., Bonfada, E., Mondino, M.G., (1991) J. Chem. Soc. Perkin Trans., 2, p. 1195 Dal Colle, M., Bertolasi, V., De Palo, M., Distefano, G., Jones, D., Modelli, A., Olivato, P.R., (1995) J. Chem. Phys., 99, p. 15011 Olivato, P.R., Guerrero, S.A., R.Rittner (1997) Phosphorus Sulfur Silicon Relat. Elem., 130, p. 155 Olivato, P.R., Bueno, E., Guerrero, S.A., Zukerman-Schpector, J., (1998) Proceedings of the 18th International Symposium on the Organic Chemistry of Sulfur, , Italy: Florence. Abstract Book Olivato, P.R., Reis, A.K.C.A., Zukerman-Schpector, J., Rittner, R., (2004) J. Mol. Struct. (Theochem), 671, p. 97 Galactic Industries Corporation, 1991-1998Guerrero, S.A., (1985), PhD. Thesis. Instituto de Química, Universidade de São PauloAltomare, A., Cascarano, G., Giacovazzo, C., Guagliardi, A., (1993) J. Appl. Cryst., 26, p. 343 Sheldrick, G.M., (1997) SHELXL97 Programs for Crystal Structure Analysis (Release 97-2), , Germany: University of Göttingen Nardelli, M., (1995) J. Appl. Cryst., 28, p. 659 Farrugia, L.J., (1999) J. Appl. Cryst., 32, p. 837 Farrugia, L.J., (1997) J. Appl. Cryst., 30, p. 565 Frisch, M.J., Trucks, G.W., Schlegel, H.B., Scuseria, G.E., Robb, M.A., Cheeseman, J.R., Zakrzewski, V.G., Pople, J.A., (1998) GAUSSIAN 98, Revision A.6, , Gaussian, Pittsburg, PA (1970) Techniques of Organic Chemistry Third Ed. Organic Solvents, 2. , J.A. Riddick, & W.B. Bunger. New York: Wiley Bellamy, L.J., (1975) Advances in Infrared Group Frequencies, , London: Chapman and Hall Gaset, A., Lafaille, A., Verdier, A., Lattes, A., (1968) Bull. Soc. Chim. Fr., p. 4108 March, J., (1985) Advanced Organic Chemistry 3rd Ed., , New York: Wiley