The sensing response of 15-crown-5-ether functionalized polythiophene to Li+, Na+, and K+ has been investigated at the atomistic level using molecular dynamics simulations. The stability associated with all the identified binding sites has been corroborated by quantum mechanical calculations. Although the cavity of the macrocycle is not the most visited binding site, such receptor is responsible of the selective sensing response of this polythiophene derivative. PF6– counterions reduce the mobility of the alkaline cations, which do not occupy the crown ether cavity of consecutive repeating units due to electrostatic repulsions. Furthermore, the relative entropy for the “free state → bound state” has been estimated using a procedure based on the covariance matrix atom-positional fluctuations. Evaluation of the entropic contributions allow us to complete the thermodynamics scenario of binding process, which was recently initiated by calculating the enthalpies at quantum mechanical level [ Chem. Eur. J. 2009, 15, 4676]. Results indicate an entropycally driven binding preference.
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机译：使用分子动力学模拟，在原子水平上研究了15-冠-5醚官能化的聚噻吩对Li +，Na +和K +的感测响应。通过量子力学计算已经证实了与所有鉴定的结合位点相关的稳定性。尽管大环的腔不是最常访问的结合位点，但是这种受体负责该聚噻吩衍生物的选择性感测响应。 PF6-抗衡离子会降低碱性阳离子的迁移率，由于静电排斥，碱性阳离子不会占据连续重复单元的冠醚腔。此外，已经使用基于协方差矩阵原子位置波动的过程来估计“自由状态→束缚状态”的相对熵。熵贡献的评估使我们能够完成结合过程的热力学场景，该过程是最近通过在量子力学水平计算焓来启动的。欧元。 J. 2009，15，4676]。结果表明由熵驱动的结合偏好。
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