The effect of substitution of phenyl and naphthyl rings to benzene was examined to elucidate the cation−π interactions involving alkali metal ions with 1,3,5-tri(phenyl)benzene (TPB) and 1,3,5-tri(naphthyl)benzene (TNB). Benzene, TPB, and four TNB isomers (with ααα, ααβ, αββ, and βββ types of fusion) and their complexes with Li⁺, Na⁺, K⁺, Rb⁺, and Cs⁺ were optimized using DFT approach with B3LYP and M06-2X functionals in conjunction with the def2-QZVP basis set. Higher relative stability of β,β,β-TNB over α,α,α-TNB can be attributed to peri repulsion, which is defined as the nonbonding repulsive interaction between substituents in the 1- and the 8-positions on the naphthalene core. Binding energies, distances between ring centroid and the metal ions, and the distance to metal ions from the center of other six-membered rings were compared for all complexes. Our computational study reveals that the binding affinity of alkali metal cations increases significantly with the 1,3,5-trisubstitution of phenyl and naphthyl rings to benzene. The detailed computational analyses of geometries, partial charges, binding energies, and ligand organization energies reveal the possibility of favorable C–H···M⁺ interactions when a α-naphthyl group exists in complexes of TNB structures. Like benzene-alkali metal ion complexes, the binding affinity of metal ions follows the order: Li⁺ > Na⁺ > K⁺ > Rb⁺ > Cs⁺ for any considered 1,3,5-trisubstituted benzene systems. In case of TNB, we found that the strength of interactions increases as the fusion point changes from α to β position of naphthalene.

中文翻译：

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碱金属离子与1,3,5-三（苯基）苯和1,3,5-三（萘基）苯的结合：DFT研究揭示了苯基和萘环取代对阳离子-π相互作用的影响

检查了苯基和萘基环对苯的取代作用，以阐明涉及碱金属离子与1,3,5-三（苯基）苯（TPB）和1,3,5-三（萘基）的阳离子-π相互作用苯（TNB）。使用B3LYP和M06的DFT方法优化了苯，TPB和四种TNB异构体（ααα，ααβ，αββ和βββ融合类型）及其与Li ⁺，Na ⁺，K ⁺，Rb ⁺和Cs ⁺的配合物-2X功能与def2-QZVP基本集一起使用。β，β，β-TNB超过α的较高的相对稳定性，α，α-TNB可以归因于关节周围排斥，定义为萘核1位和8位取代基之间的非键排斥相互作用。比较了所有配合物的结合能，环质心与金属离子之间的距离以及与其他六元环中心到金属离子的距离。我们的计算研究表明，碱金属阳离子的结合亲和力随着苯基和萘环与苯的1,3,5-三取代而显着增加。对几何形状，部分电荷，结合能和配体组织能的详细计算分析揭示了有利的C–H···M ⁺的可能性。TNB结构的复合物中存在α-萘基时发生相互作用。像苯-碱金属离子络合物一样，对于任何考虑的1,3,5-三取代苯体系，金属离子的结合亲和力都遵循以下顺序：Li ⁺ > Na ⁺ > K ⁺ > Rb ⁺ > Cs ⁺。在TNB的情况下，我们发现相互作用的强度随着萘的熔点从α位置变化到β位置而增加。