CREST, JST, and Research Initiative of Computational Sciences (RICS), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, Japan.
J Phys Chem A. 2011 Oct 20;115(41):11256-62. doi: 10.1021/jp2045756. Epub 2011 Aug 3.
The CH/π contact structures of the fucose-phenol and fucose-indole complexes and the stabilization energies by formation of the complexes (E(form)) were studied by ab initio molecular orbital calculations. The three types of interactions (CH/π and OH/π interactions and OH/O hydrogen bonds) were compared and evaluated in a single molecular system and at the same level of theory. The E(form) calculated for the most stable CH/π contact structure of the fucose-phenol complex at the CCSD(T) level (-4.9 kcal/mol) is close to that for the most stable CH/π contact structure of the fucose-benzene complex (-4.5 kcal/mol). On the other hand the most stable CH/π contact structure of the fucose-indole complex has substantially larger E(form) (-6.5 kcal/mol). The dispersion interaction is the major source of the attraction in the CH/π contact structures of the fucose-phenol and fucose-indole complexes as in the case of the fucose-benzene complex. The electrostatic interactions in the CH/π contact structures are small (less than 1.5 kcal/mol). The nature of the interactions between the nonpolar surface of the carbohydrate and aromatic rings is completely different from that of the conventional hydrogen bonds where the electrostatic interaction is the major source of the attraction. The distributed multipole analysis and DFT-SATP analysis show that the dispersion interactions in the CH/π contact structure of fucose-indole complex are substantially larger than those in the CH/π contact structures of fucose-benzene and fucose-phenol complexes. The large dispersion interactions are responsible for the large E(form) for the fucose-indole complex.
通过从头算分子轨道计算研究了岩藻糖-苯酚和岩藻糖-吲哚复合物的 CH/π 接触结构以及形成复合物的稳定能 (E(form))。在单个分子体系中和在相同理论水平上比较和评估了三种相互作用 (CH/π 和 OH/π 相互作用以及 OH/O 氢键)。在 CCSD(T) 水平下计算的最稳定的岩藻糖-苯酚复合物的 CH/π 接触结构的 E(form)(-4.9 kcal/mol)接近于最稳定的岩藻糖-苯复合物的 CH/π 接触结构的 E(form)(-4.5 kcal/mol)。另一方面，岩藻糖-吲哚复合物的最稳定的 CH/π 接触结构具有显著更大的 E(form)(-6.5 kcal/mol)。在岩藻糖-苯酚和岩藻糖-吲哚复合物的 CH/π 接触结构中，色散相互作用是吸引力的主要来源，就像在岩藻糖-苯复合物的情况下一样。在 CH/π 接触结构中的静电相互作用很小 (小于 1.5 kcal/mol)。碳水化合物的非极性表面与芳环之间相互作用的性质与传统氢键完全不同，其中静电相互作用是吸引力的主要来源。分布式多极分析和 DFT-SATP 分析表明，岩藻糖-吲哚复合物的 CH/π 接触结构中的色散相互作用显著大于岩藻糖-苯和岩藻糖-苯酚复合物的 CH/π 接触结构中的色散相互作用。大的色散相互作用是岩藻糖-吲哚复合物具有大的 E(form)的原因。
