Wydział Chemii

Halina Szatyłowicz

Tadeusz M. Krygowski

Aneta Jezierska

Jarosław J. Panek

2009

Journal of Physical Chemistry A

113

5800-5805

10.1021/jp8109258

Naukowa

Angielski

Artykuł

We were able to test the Bent-Walsh rule by examining geometric parameters in the vicinity of the ipso-carbon atom of H-bonded complexes of para-substituted phenol/phenolate and aniline/anilide derivatives for the three cases (i) a versus α, (ü) α versus d_co or d _cn, and (iü) a versus d_co or d_cn, where a is the ring valence angle at the ipso-carbon atom (C1 substituted by OH or O^- or NH₂ or NH^-) and a is the arithmetic mean of the two C_ipso-C_ortho bond lengths. The data for nonequilibrium H-bonded complexes of unsubstituted phenol/phenolate and aniline/anilide with the respective bases F^- and CIST and acids HF and HCN showed the same dependence of a on d_cx (X = O, N) as the data for equilibrium complexes of para-Y-substituted phenol/phenolate and aniline/anilide derivatives (Y = NO, NO₂, CHO, COMe, CONH ₂, Cl, F, H, Me, OMe, OH) with the same bases and acids. The slope of these dependencies was negative, as expected. In the remaining cases (a versus α and α versus d_co or d_cn), the slopes for simulated complexes followed the Bent-Walsh rule. Finally, for the equilibrium complexes in which the substituent effect was included, the slopes of the trend lines for the substituted systems were opposite. This is because in the a versus α relationships, electonegativity and the resonance effect act in the same direction, whereas for the other two cases, these effects are opposite, and the resonance effect dominates.

http://dx.doi.org/10.1021/jp8109258

https://www.acs.org/content/acs/en.html