Although early transition metal (ETM) carbides can activate CH bonds in condensed‐phase systems, the electronic‐level mechanism is unclear. Atomic clusters are ideal model systems for understanding the mechanisms of bond activation. For the first time, CH activation of a simple alkane (ethane) by an ETM carbide cluster anion (MoC₃⁻) under thermal‐collision conditions has been identified by using high‐resolution mass spectrometry, photoelectron imaging spectroscopy, and high‐level quantum chemical calculations. Dehydrogenation and ethene elimination were observed in the reaction of MoC₃⁻ with C₂H₆. The CH activation follows a mechanism of oxidative addition that is much more favorable in the carbon‐stabilized low‐spin ground electronic state than in the high‐spin excited state. The reaction efficiency between the MoC₃⁻ anion and C₂H₆ is low (0.23±0.05) %. A comparison between the anionic and a highly efficient cationic reaction system (Pt⁺+C₂H₆) was made. It turned out that the potential‐energy surfaces for the entrance channels of the anionic and cationic reaction systems can be very different.

中文翻译：

---

C ？早期过渡金属碳化物簇阴离子MoC3-的H键活化

尽管早期过渡金属（ETM）碳化物可以在凝聚相系统中激活CH键，但电子能级机制尚不清楚。原子簇是理解键活化机理的理想模型系统。首次，C  H A简单烷烃（乙烷）由ETM碳化物簇阴离子的活化（MOC ₃ ^- ）的热碰撞条件已被确定，通过使用高分辨率质谱，光电子摄像光谱下，和高级量子化学计算。脱氢和乙烯消除moc的反应中观察到₃ ^-为C ₂ ħ ₆。的C H活化遵循一种氧化加成机理，在碳稳定的低自旋基态电子状态下，比在高自旋激发态下更有利。在交通部之间的反应效率₃ ^-阴离子和C ₂ H ^ ₆为低（0.23±0.05）％。进行了阴离子和高效阳离子反应体系（Pt ⁺ + C ₂ H ₆）的比较。事实证明，阴离子和阳离子反应系统入口通道的势能表面可能非常不同。