A combined study based on experiment and molecular dynamics: perylene tetracarboxylate intercalated in a layered double hydroxide matrix.
A combined study based on experiment and molecular dynamics: perylene tetracarboxylate intercalated in a layered double hydroxide matrix.
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DOI：
10.1039/b907366c
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发表时间：
2009-10
期刊：
影响因子：
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通讯作者：
Dongpeng Yan;Jun Lu;Min Wei;Jing Ma;D. Evans;X. Duan
中科院分区：
文献类型：
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作者：
Dongpeng Yan;Jun Lu;Min Wei;Jing Ma;D. Evans;X. Duan
本文描述了对 3,4,9,10-苝四羧酸酯 (PTCB) 插层镁铝层状双氢氧化物 (PTCB/Mg-Al-LDH) 的光物理性质、热解和取向的实验和理论模拟相结合的研究。紫外可见吸收和荧光光谱显示 LDH 通道内存在 PTCB 聚集体，表明 H 型（蓝移吸收带）和 J 型二聚体（红移吸收带）。采用原位高温X射线衍射（HT-XRD）、热重和差热分析（TG-DTA）以及元素分析研究了PTCB/Mg-Al-LDH的热分解性能，发现插层PTCB的分解温度低于其原始形式（460 vs 565℃），这表明： PTCB 之间强的 pi-pi 相互作用被带正电荷的 LDH 主层削弱。采用分子动力学（MD）计算来模拟插层PTCB在Mg-Al-LDH画廊中的分子排列和聚集行为。模拟结果表明，随着层间含水量的增加，插入的PTCB阴离子表现出相对于层从倾斜取向到垂直取向的趋势，此外，H型和J型二聚体最有可能分别在低水合条件和高水合条件下填充。此外，还讨论了层间水分子的分布。
This paper describes a combined experimental and theoretical simulation investigation on the photophysical properties, thermolysis, and orientation of 3,4,9,10-perylene tetracarboxylate (PTCB) intercalated Mg-Al-layered double hydroxide (PTCB/Mg-Al-LDH). UV-vis absorption and fluorescence spectroscopy show the existence of PTCB aggregates within the gallery of LDH, indicative of H-type (blue-shifted absorption band) and J-type dimers (red-shifted absorption band). In situ high-temperature X-ray diffraction (HT-XRD), thermogravimetry and differential thermal analysis (TG-DTA) and elemental analysis were used to study the thermal decomposition properties of PTCB/Mg-Al-LDH, and it was found that the decomposition temperature of the intercalated PTCB is lower than its pristine form (460 vs 565 degrees C), indicating that the strong pi-pi interaction among PTCB was weakened by the positively charged LDH host layers. Molecular dynamics (MD) calculations were employed to simulate the molecular arrangement and aggregation behavior of intercalated PTCB in the gallery of Mg-Al-LDH. The simulation results show that the intercalated PTCB anions exhibit a tendency from tilted to vertical orientation with respect to the layers as the interlayer water content increases, furthermore, the H and J-type dimer species are most likely populated under low and high hydration conditions, respectively. Moreover, the distribution of interlayer water molecules are also discussed.