Li Ying, Wang Ming, Ding Yong-Qi, Zhao Chong-Yang, Ma Jia-Bi
Key Laboratory of Cluster Science of Ministry of Education, Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 102488, P. R. China.
Phys Chem Chem Phys. 2021 Jun 9;23(22):12592-12599. doi: 10.1039/d1cp01418h.
Cleavage of all C-H bonds in two methane molecules by gas-phase cluster ions at room temperature is a challenging task. Herein, mass spectrometry and quantum chemical calculations have been used to identify one single metal boride cluster anions NbB4- that can activate eight C-H bonds in two methane molecules and release one H2 molecule each time under thermal collision conditions. In these consecutive reactions, the loaded Nb atoms and the support B4 units play different roles but act synergistically to activate CH4, which is responsible for the interesting reactivity of NbB4-. Moreover, there are some mechanistic differences in these two reactions, including the mechanisms for the first C-H bond activation steps, dihydrogen desorption sites, and major electron donors. This study shows that non-noble metal boride species are reactive enough to facilitate thermal C-H bond cleavages, and boron-based materials may be one kind of potential support material facilitating surface hydrogen transport.
在室温下，通过气相团簇离子裂解两个甲烷分子中的所有碳氢键是一项具有挑战性的任务。在此，利用质谱和量子化学计算确定了一种单一的金属硼化物团簇阴离子NbB4-，它可以在热碰撞条件下激活两个甲烷分子中的八个碳氢键，并每次释放一个氢气分子。在这些连续反应中，负载的铌原子和载体B4单元发挥不同作用，但协同作用以激活甲烷，这就是NbB4-具有有趣反应活性的原因。此外，这两个反应存在一些机理差异，包括第一个碳氢键活化步骤的机理、氢气脱附位点和主要电子供体。这项研究表明，非贵金属硼化物物种具有足够的反应活性来促进热碳氢键裂解，并且硼基材料可能是一类促进表面氢传输的潜在载体材料。
