Artículos de revistas
Lone-pair orientation effect of an alpha-oxygen atom on (1)J(CC) NMR spin-spin coupling constants in o-substituted phenols. Experimental and DFT study
Registro en:
Journal Of Chemical Theory And Computation. Amer Chemical Soc, v. 3, n. 4, n. 1284, n. 1294, 2007.
1549-9618
WOS:000247893400006
10.1021/ct7000396
Autor
Taurian, OE
Contreras, RH
De Kowalewski, DG
Perez, JE
Tormena, CF
Institución
Resumen
The well-known N lone-pair orientation effect on (1)J(CC) spin-spin coupling constants (SSCCs) in oximes and their derivatives was used to study how negative hyperconjugative interactions of type LP1(O) -> sigma* CC depend on ortho interactions involving the OH group. This study demanded the following analyses: (i) a qualitative estimation of how (1)J(CC) SSCCs are affected by hyperconjugative interactions, ( ii) a study of similar stereochemical effects to those in oximes, but in (1)J(C1C2) and (1)J(C1C6) in a series of 2-substituted phenols, and ( iii) a quantitative estimation, with the natural bond order approach, of some key electron delocalization interactions. A few unexpected results are quoted. LP1(O) -> sigma* cc interactions are affected by proximity interactions as follows: ( a) they are enhanced by hydrogen bonds transferring charge into the (O-H)* antibonding orbital; (b) they are enhanced by proximity interactions of type LP1(O)center dot center dot center dot H-C; (c) they are inhibited by interactions of type LP(O-1)center dot center dot center dot H-O. Consequences of these observations are discussed. 3 4 1284 1294