Uetake Yuriko, Takemura Hiroyuki
Department of Chemical and Biological Sciences, Faculty of Science, Japan Women's University, Mejirodai 2-8-1, Bunkyo-ku, Tokyo 112-8681, Japan.
Molecules. 2024 Aug 23;29(17):3987. doi: 10.3390/molecules29173987.
Pi-stacked and box-shaped host molecules with xanthene as the basis and pyrene as the π-plane were synthesized to verify cation-π interactions between graphene and metal cations. Since crystal structure analysis was not available, DFT calculations were performed to determine the optimized structure, and the π-planes were found to have a slipped parallel structure, with average distances of 456.2-581.0 pm for the stacked compound and 463.4-471.4 pm for the box-shaped compound. Li and Ag were chosen as acceptors for complexation with metal ions, and their interactions with the π-plane were clarified by NMR titration. Clearly, the interaction with metal ions increased when pyrene π-planes were stacked rather than the pyrene itself. In the stacked compound, the association constants of Ag and Li were similar; however, in the box-shaped host molecule, only Ag had moderate coordination ability, but the interaction with Li was very weak, comparable to the interaction with pyrene. As a result, intercalation is more likely to occur in stacked host compound , which has some degree of freedom in the pyrene rings, than in the box-shaped compound.
合成了以呫吨为基础、芘为π平面的π堆积和盒状主体分子，以验证石墨烯与金属阳离子之间的阳离子-π相互作用。由于无法进行晶体结构分析，因此进行了密度泛函理论（DFT）计算以确定优化结构，发现π平面具有滑移平行结构，堆积化合物的平均距离为456.2 - 581.0皮米，盒状化合物的平均距离为463.4 - 471.4皮米。选择锂和银作为与金属离子络合的受体，并通过核磁共振滴定阐明它们与π平面的相互作用。显然，当芘π平面堆积而不是芘本身时，与金属离子的相互作用增强。在堆积化合物中，银和锂的缔合常数相似；然而，在盒状主体分子中，只有银具有适度的配位能力，但与锂的相互作用非常弱，与芘的相互作用相当。结果，与盒状化合物相比，堆积主体化合物中芘环具有一定自由度，更有可能发生插层。
