Artículos de revistas
A Conformational Analysis Of Some α-aryloxy P-substituted-acetophenones: Solvent Effects On The Vco Infrared Bands
Registro en:
Canadian Journal Of Analytical Sciences And Spectroscopy. , v. 48, n. 3, p. 181 - 188, 2003.
12056685
2-s2.0-0041330339
Autor
Guerrero S.A.
Olivato P.R.
Rittnerb R.
Institución
Resumen
The vco analysis of the α-(p-substituted-phenoxy)p′-substituted-acetophenones [X-Ph-C(O)-CH2-OPh-Y; X=NO2, Y=OMe (1); X= NO 2″, H (2); X=NO2, Y= NO2 (3); X=H, Y=OMe (4); X= H, Y=H (5); X= H, NO2 (6); X=OMe, Y= OMe (7); X=OMe, H (8); X=OMe, NO2 (9)] indicates the existence of cis (I)gauche (II) rotational isomerism. For compounds 12, an additional gauche rotamer (II′) is detected in carbon tetrachloride solution. The almost constant positive carbonyl wavenumber shifts for the cis rotamers of 3-9 are interpreted as due to electronic effects (F, -Iσ and M), whose summing up gives rise to a similar carbonyl bond order. This suggests that the cis rotamer has a similar energy in the whole series. The decrease in the cis/gauche population ratio on going from electron attracting to electron donating substituents within the series 4-6 and 7-9, along with a larger population of the gauche rotamer for 1-3, is discussed in terms of π*CO(LUMO)/n O(OPh-Y) orbital interaction, which stabilises the gauche rotamer for 1-9. Further support for this interpretation is given by the progressive negative carbonyl wavenumber shifts for the gauche rotamers within the series 4-6 and 7-9 on going from electron attracting to electron donating substituents at the phenoxy group, along with the largest negative carbonyl wavenumber gauche shifts for the nitrophenacyl derivatives 1-2. 48 3 181 188 Olivato, P.R., Guerrero, S.A., Martins, E.A.L., (1989) Phosphorus Sulfur, 44, p. 9 Olivato, P.R., Guerrero, S.A., (1992) Phosphorus Sulfur, 66, p. 207 Olivato, P.R., Guerrero, S.A., Hui, M.L.T., Mattos, J., Harms, S., Schmidt, M.S.V., Rittner, R., (1999) Spectrosc. Lett., 32, p. 1041 Heidelberger, J., (1945) J. Biol. Chem., 21, p. 459 Murray, R.W., Jeyaraman, R., Mohan, L., (1986) Tetrahedron Lett., 27, p. 2335 Yates, P., Farnum, D.G., Stout, G.H., (1956) J. Am. Chem. Soc., 80, p. 196 Baker, W., Polland, A., Robinson, R., (1929) J. Chem. Soc., p. 1468 Arnall, F., (1924) J. Chem. Soc., 125, p. 811 Baker, B.R., Hurlbut, J.A., (1967) J. Med. Chem., 10, p. 1129 Davies, W., Middleton, S., (1958) J. Chem. Soc., pp. 822-825 Palm, W.-U., Dreeskamp, H., Bouaas-Laurent, H., Castellan, A., (1992) Ber. Bunsenges Phys. Chem., 96, p. 50 Palmer, M.H., McVie, G.J., (1968) J. Chem. Soc. (B), p. 856 Galactic Ind. Corp., 1991-1998Olivato, P.R., Guerrero, S.A., Rittner, R., (1997) Phosphorus Sulfur, 130, p. 155 Bellamy, L.J., (1975) Advances in Infrared Group Frequencies, p. 143. , Chapman and Hall, London Gaset, A., Lafaille, L., Verdier, A., Lattes, A., (1968) Bull. Soc. Chim. Fr., 4108 Katritsky, A.R., Topsom, R.D., (1989) Chem. Rev., 77, p. 639 Distefano, G., Dal Colle, M., unpublished resultsHansch, C., Leo, A., Hoekman, D., (1995) Exploring QSAR. Hydrophobic Electronic and Steric Constants, , American Chemical Society, Washington Bernardi, F., Distefano, G., Mangini, A., Pignataro, J., Spunta, G., (1975) J. Electron Spectrosc. Relat. Phenom., 7, p. 475 Dewar, M.J., Dougherty, R.C., (1975) The PMO Theory of Organic Chemistry, , Plenum Press, New York