Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.
Phys Chem Chem Phys. 2011 Jun 7;13(21):10084-90. doi: 10.1039/c0cp02095h. Epub 2011 Apr 26.
The Sc(3)O(6)(-) cluster anions were produced by laser ablation and studied by reaction with n-butane in a fast flow reactor and by photoelectron spectroscopy. The reactivity experiments indicated that one Sc(3)O(6)(-) cluster can activate two n-butane molecules consecutively with rate constants on the order of 10(-10) cm(3) molecule(-1) s(-1) under near room-temperature conditions, suggesting that the even-electron system Sc(3)O(6)(-) has a highly reactive electronic structure. The photoelectron spectroscopy determined a high vertical detachment energy (VDE) of 5.63 ± 0.08 eV for the Sc(3)O(6)(-) cluster. Density functional computations indicated that the lowest energy isomer of Sc(3)O(6)(-) is an oxygen-centered biradical with a high VDE and is highly reactive toward n-butane, which is in good agreement with the experiments. The Sc(3)O(6)(-) cluster may serve as an ideal model system to provide insight into the real-life chemistry involved with the coupled O(-)˙···O(-)˙ dimers over the surfaces of metal oxide catalysts.
Sc(3)O(6)(-) 簇阴离子通过激光烧蚀产生，并通过在快速流动反应器中与正丁烷反应以及光电电子能谱进行研究。反应实验表明，在接近室温的条件下，一个 Sc(3)O(6)(-) 簇可以连续激活两个正丁烷分子，速率常数在 10(-10) cm(3) 分子(-1) s(-1) 左右，这表明具有偶数电子体系的 Sc(3)O(6)(-) 具有高度反应性的电子结构。光电电子能谱确定 Sc(3)O(6)(-) 簇的垂直离解能 (VDE) 为 5.63 ± 0.08 eV。密度泛函计算表明，Sc(3)O(6)(-) 的最低能量异构体是一个以氧为中心的双自由基，具有较高的 VDE，对正丁烷具有很高的反应活性，这与实验结果一致。Sc(3)O(6)(-) 簇可能是一个理想的模型体系，可以深入了解金属氧化物催化剂表面上耦合 O(-)···O(-)··· 二聚体的实际化学反应。
