Cation-π interaction in cofacial molecular dyads: a DFT and TDDFT study
Cation-π interaction in cofacial molecular dyads: a DFT and TDDFT study
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DOI：
10.1039/c6ra10368e
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发表时间：
2016-01-01
期刊：
影响因子：
3.9
通讯作者：
Bania, Kusum K.
中科院分区：
文献类型：
--
作者：
Mahanta, Sanjeev Pran;Dutta, Biswajyoti;Bania, Kusum K.
在这项研究中，我们提出了一个共面分子二联体或镊子（4，5-联苯吖啶，BPA）与吖啶部分作为间隔和两个苯环作为翅膀。密度泛函理论（DFT）计算表明苯环通过阳离子-π相互作用在稳定阳离子（Li+、Na+或K+）中的关键作用。我们的计算表明，除了共价相互作用，阳离子π相互作用能有助于稳定的阳离子内的分子口袋。取代基对阳离子-π络合物的结构和相互作用能的影响也被举例说明。给电子基团有利于阳离子-π相互作用，而吸电子基团降低阳离子-π相互作用的强度。发现溶剂极性在稳定阳离子-π相互作用中起关键作用。具有低介电常数的溶剂主要有利于这种相互作用，而高极性溶剂导致排斥相互作用能。TDDFT（含时密度泛函理论）的计算进行，以了解阳离子π相互作用的吸收光谱上的这种分子二联体的效果。
In this study we proposed a cofacial molecular dyad or a tweezer (4,5-biphenyl acridine, BPA) with the acridine moiety serving as the spacer and two phenyl rings as the wings. Density functional theory (DFT) calculation was implemented to illustrate the pivotal role of the phenyl rings in stabilizing the cation (Li+, Na+ or K+) at the tweezers via cation-pi interaction. Our calculations reveal that apart from the covalent interaction, the cation-pi interaction energy contributes to the stabilization of cations inside the molecular pocket. The effect of substituents on the structure and interaction energy of the cation-pi complexes was also exemplified. An electron donating group favored the cation-pi interaction while an electron withdrawing group lowered the strength of cation-pi interaction. Solvent polarity was found to play a critical role in stabilizing the cation-pi interaction. Solvents with a low dielectric constant mostly favored such interaction while highly polar solvents resulted in repulsive interaction energy. TDDFT (time dependent density functional theory) calculations were performed to understand the effect of the cation-pi interaction on the absorption spectra of such molecular dyads.