Ahmed Usman, Daub Christopher D, Sundholm Dage, Johansson Mikael P
Department of Chemistry, Faculty of Science, University of Helsinki, P. O. Box 55 (A. I. Virtasen aukio 1), FI-00014, Helsinki, Finland.
CSC-IT Center for Science Ltd, P.O. Box 405, FI-02101 Espoo, Finland.
Phys Chem Chem Phys. 2024 Sep 25;26(37):24470-24476. doi: 10.1039/d4cp02361g.
Molecular self-assembly provides the means for creating large supramolecular structures, extending beyond the capability of standard chemical synthesis. To harness the power of self-assembly, it is necessary to understand its driving forces. A potent method is to exploit self-complementary hydrogen bonding, where a molecule interacts with its own copy by suitable positions of hydrogen-bond donor (D) and acceptor (A) groups. With four hydrogen bonds, there are two possible self complementary patterns: the DDAA/AADD and the DADA/ADAD motifs. Of these, the DDAA pattern is usually more stable. The traditional explanation assumes that the secondary interactions between equal groups, that is, between donors (D⋯D) or acceptors (A⋯A), are repulsive. DDAA arrays would then have two, and DADA arrays six repulsive interactions. Here, using high-end quantum chemical analysis, we show that contrary to the traditional explanation, the secondary A⋯A interactions are, in fact, attractive. We revise the model of secondary interactions accordingly.
分子自组装为创建超越标准化学合成能力的大型超分子结构提供了手段。为了利用自组装的力量，有必要了解其驱动力。一种有效的方法是利用自互补氢键，即分子通过氢键供体（D）和受体（A）基团的合适位置与自身的拷贝相互作用。有四个氢键时，有两种可能的自互补模式：DDAA/AADD和DADA/ADAD基序。其中，DDAA模式通常更稳定。传统解释认为，相同基团之间的次级相互作用，即供体（D⋯D）或受体（A⋯A）之间的相互作用是排斥性的。那么DDAA阵列将有两个排斥相互作用，而DADA阵列将有六个排斥相互作用。在这里，我们使用高端量子化学分析表明，与传统解释相反，次级A⋯A相互作用实际上是吸引性的。我们据此修订了次级相互作用模型。
