Mechanochemistry in [6]Cycloparaphenylene: A Combined Raman Spectroscopy and Density Functional Theory Study.
Mechanochemistry in [6]Cycloparaphenylene: A Combined Raman Spectroscopy and Density Functional Theory Study.
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[6]环对亚苯基中的机械化学：拉曼光谱和密度泛函理论相结合的研究。
DOI：
10.1002/cphc.201800319
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
M. Kertész
中科院分区：
文献类型：
--
作者：
Lili Qiu;M. Peña‐Álvarez;V. Baonza;M. Taravillo;J. Casado;M. Kertész
将高达 10 GPa 的高压下的拉曼光谱和高达 30 GPa 的密度泛函计算相结合，以深入了解原型纳米环共轭分子 [6] 环对亚苯基 ([6]CPP) 的行为。当压力增加时，纳米环会发生变形，首先是可逆的椭圆化，然后在更高的压力下形成聚集体。这种不可逆的聚集是由新的分子间σ键的形成引起的。计算很好地再现了作为压力函数的拉曼频移的频率和导数。频率行为与纳米环的芳香/醌类特征的变化有关。中等高压下的建模揭示了 [6]CPP 分子变形为椭圆形和花生形。令人惊讶的是，观察到的拉曼模式转变的压力导数在所有拉曼模式共有的压力值周围发生突然变化，表明计算模型解释了整个分子上延伸的潜在几何变化。模拟预测，在更高压力引起的更大变形下，将会引发低聚反应。我们的模拟表明，无论溶剂如何，这些转变都会发生，但是发生这些转变的压力受到封装在 [6]CPP 内部的溶剂分子的影响。
Raman spectroscopy under high pressures up to 10 GPa and density functional computations up to 30 GPa are combined to obtain insights into the behavior of a prototypical nanohoop conjugated molecule, [6]cycloparaphenylene ([6]CPP). Upon increasing pressure, the nanohoop undergoes deformations, first reversible ovalization and then at even higher pressures aggregates are formed. This irreversible aggregation is caused by the formation of new intermolecular σ-bonds. Frequencies and derivatives of the Raman frequency shifts as a function of pressure are well reproduced by the computations. The frequency behavior is tied to changes in aromatic/quinonoid character of the nanohoop. The modeling at moderate high pressures reveals the deformation of the [6]CPP molecules into oval-like and peanut-like shapes. Surprisingly the pressure derivatives of the observed Raman mode shifts undergo a sudden change around a pressure value that is common to all Raman modes, indicating an underlying geometrical change extended over the whole molecule that is interpreted by the computational modeling. Simulations predict that under even larger deformations caused by higher pressures, oligomerization reactions would be triggered. Our simulations demonstrate that these transformations would occur regardless of the solvent, however pressures at which they happen are influenced by solvent molecules encapsulated in the interior of the [6]CPP.
影响因子：
15
作者：
Ong, Mitchell T.;Leiding, Jeff;Martinez, Todd J.
通讯作者：
Martinez, Todd J.