Effect of xenon on fullerene reactions
Effect of xenon on fullerene reactions
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DOI：
10.1021/ja075568n
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发表时间：
2007-10-31
影响因子：
15
通讯作者：
Saunders, Martin
中科院分区：
文献类型：
--
作者：
Frunzi, Michael;Cross, R. James;Saunders, Martin
让含有 He-3@C-60、129Xe@C-60 和不同量的 9,10-二甲基蒽 (DMA) 的溶液达到平衡，并在相同温度下获取 He-3 和 Xe-129 NMR 谱。每个光谱均显示未反应的 X@C-60 和单加合物的峰。峰高比表明，所包含的氙原子显着改变了平衡常数。这种变化与温度有关，这意味着氙原子会改变反应的 Delta H 和 Delta S。 DMA 在低温下与 He@C-60 更具反应性，在较高温度下与 Xe@C-60 更具反应性。 Xe 的单加合物和未反应的 X@C-60 之间的化学位移差异是 He 的两倍多，且方向相反。计算表明，Xe@C-60 中的电子密度高于笼外空 C-60 中的电子密度。
Solutions containing He-3@C-60, 129Xe@C-60, and varying amounts of 9,10-dimethylanthracene (DMA) were allowed to reach equilibrium, and the He-3 and Xe-129 NMR spectra were taken at the same temperature. Each spectrum showed peaks for the unreacted X@C-60 and for the monoadduct. The ratios of the peak heights show that the included xenon atom substantially changes the equilibrium constant. This change is temperature dependent, meaning that the xenon atom changes both Delta H and Delta S for the reaction. DMA is more reactive with He@C-60 at low temperatures and with Xe@C-60 at higher temperatures. The difference in chemical shift between the monoadduct and the unreacted X@C-60 is more than twice as large for Xe than for He and in the opposite direction. Calculations show that the electron density in Xe@C-60 is higher than that in empty C-60 on the outside of the cage.