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首页> 外文会议>Advances in Computational Methods in Sciences and Engineering 2005 vol.4A; Lecture Series on Computer and Computational Sciences; vol.4A >Effect of the Entropy Compensation on the Stability of Host-Guest Complexes Applied in Selective Chemical Sensors
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Effect of the Entropy Compensation on the Stability of Host-Guest Complexes Applied in Selective Chemical Sensors

机译：熵补偿对选择性化学传感器中客体-客体配合物稳定性的影响

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摘要

The π-π interaction-based inclusion complexation of calix[6]arene hexasulfonate as host with neutral aromatic guest molecules was studied in aqueous media using both experimental and theoretical methods. Experimental measurements (PL and DSC) showed an increased complex stability when the electron density on the guest's aromatic rings increased, although the enthalpy change lowered. The evaluation of the thermodynamic parameters of the complex formation (enthalpy, entropy and Gibbs free energy) highlighted the excessive role of the entropy term in this particular case. To obtain atomistic view on the complex formation, DFT/B3LYP/6-31++G method and molecular dynamics simulation were performed. The stability of the complex and the complex formation were evaluated considering the Hammett parameters of the substituents of the guest. The entropy term of the complex formation was studied by simulation of the molecular rearrangement of solvent water molecules around the calixarene host when the phenol derivatives with their differently polarized aromatic rings enter into the calixarene cavity. The results show a structure of higher order of the water molecules when the aromatic ring of the entering guest molecule is electron-deficient. These results can contribute to the development of selective and sensitive chemical sensors for aromatic organic analytes.
机译：在水介质中使用实验和理论方法研究了杯芳烃[6]芳烃六磺酸盐与主体与中性芳族客体分子的基于π-π相互作用的包合配合物。实验测量（PL和DSC）显示，当宾客芳环上的电子密度增加时，尽管焓变降低，但复杂稳定性增加。对复合物形成的热力学参数（焓，熵和吉布斯自由能）的评估突出了熵项在这种特殊情况下的过度作用。为了获得复合物形成的原子观，进行了DFT / B3LYP / 6-31 ++ G方法和分子动力学模拟。考虑到客体取代基的哈米特参数，评估了配合物的稳定性和配合物的形成。通过模拟杯水芳烃主体周围溶剂水分子的分子重排，当酚衍生物及其不同极化的芳香环进入杯水芳烃腔时，研究了络合物形成的熵项。结果表明，当进入的客体分子的芳环缺乏电子时，水分子的结构更高。这些结果可有助于开发用于芳香族有机分析物的选择性和灵敏化学传感器。

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