Computational Studies on the Stability of [Amide]Br- Complexes
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- 作者：Michal
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- 刊名：Journal of Physical Chemistry A
- 出版年：1999
- 出版时间：May 13, 1999
- 年：1999
- 卷：103
- 期：19
- 页码：3778 - 3782
- 全文大小：88K
- 年卷期：v.103,no.19(May 13, 1999)
- ISSN：1520-5215
文摘
Theoretical studies on supramolecules have provided insight into their structure as well as their electronicdistribution. While a number of such studies are found in the literature for neutral or cationic receptors, muchless is known about anionic systems. Recently, we have published (Stibor, I.; Haffed, D. S. M.; Lhoták, P.;Hoda
ová, J.; Koa, J.; 
ajan, M. Gazz. Chim. Ital. 1997, 127, 673) a study of amide bond activation foranion complexation where association constants were measured. In this paper, we present the results ofcalculations on single amides substituted on both sides of the amidic bond by an aromatic group with differentsubstituents, as well as their complexes with anions using different methods of energy calculations. It isrevealed that (i) only DFT methods give realistic results, while neither semiempirical quantum chemistry normolecular mechanics CVFF force field give a realistic insight; (ii) the ligands (amides) themselves exhibit adifferent scale of nonplanarity which is caused by the repulsion between the ortho substituents of the aromaticmoieties and the oxygen atom of the amidic group; (iii) the stability of the complexes is mainly correlated tothree factors, the length of the hydrogen bond between the anion and amidic hydrogen, the interaction energyfor the calculated complex, and the charge on the bromine atom within the complex.
ová, J.; Koa, J.; ajan, M. Gazz. Chim. Ital. 1997, 127, 673) a study of amide bond activation foranion complexation where association constants were measured. In this paper, we present the results ofcalculations on single amides substituted on both sides of the amidic bond by an aromatic group with differentsubstituents, as well as their complexes with anions using different methods of energy calculations. It isrevealed that (i) only DFT methods give realistic results, while neither semiempirical quantum chemistry normolecular mechanics CVFF force field give a realistic insight; (ii) the ligands (amides) themselves exhibit adifferent scale of nonplanarity which is caused by the repulsion between the ortho substituents of the aromaticmoieties and the oxygen atom of the amidic group; (iii) the stability of the complexes is mainly correlated tothree factors, the length of the hydrogen bond between the anion and amidic hydrogen, the interaction energyfor the calculated complex, and the charge on the bromine atom within the complex.