Ramero Carlos, Guadarrama Patricia, Fomine Serguei
Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, Apartado Postal 70-360, CU, Coyoacán, 04510, México, México.
J Mol Model. 2005 Dec;12(1):85-92. doi: 10.1007/s00894-005-0009-7. Epub 2005 Oct 28.
A theoretical analysis of the nature of the interactions in dibenzo[24]crown-8 (DB24C8)-n-dibutylammonium (DBM)--pseudorotaxane complex at the MP2 and DFT levels shows that the main contribution to the binding energy is the electrostatic interaction with moderate (20-25%) correlation stabilization. The total binding energy in the DB24C8-DBM complex represents a sum of the binding energies of two NH-O and one CH-O hydrogen bonds and the latter constitutes about 25% of the total interaction energy, giving the total binding energy of -41.2 kcal mol(-1) at the BHandHLYP/6-311 + + G** level. Deprotonation of the DB24C8-DBM complex reduces the binding energy by some 50 kcal mol(-1), giving metastable complexes DB24C8-DBA-1 or DB24C8-DBA-2, which will dissociate to give free crown ether and n-dibutylamine because of the strong exchange repulsion that prevails in neutral complexes.
在MP2和DFT水平上对二苯并[24]冠-8（DB24C8）-正二丁基铵（DBM）-准轮烷配合物中相互作用本质的理论分析表明，对结合能的主要贡献是静电相互作用，伴有适度（20 - 25%）的相关稳定化。DB24C8 - DBM配合物中的总结合能是两个NH - O和一个CH - O氢键结合能的总和，后者约占总相互作用能的25%，在BHandHLYP/6 - 311 + + G**水平下给出的总结合能为 - 41.2 kcal mol⁻¹。DB24C8 - DBM配合物的去质子化使结合能降低约50 kcal mol⁻¹，产生亚稳配合物DB24C8 - DBA - 1或DB24C8 - DBA - 2，由于中性配合物中占主导的强交换排斥作用，它们会解离生成游离的冠醚和正二丁胺。
