On the Origin of the Distinctly Different Reactivity of Ruthenium in [MO]+/CH4 Systems (M=Fe, Ru, Os)

Xiaoyan Sun; Shaodong Zhou; Lei Yue; Maria Schlangen; Helmut Schwarz

Index: 10.1002/anie.201800173

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Abstract

The thermal gas‐phase reactions of [RuO]+ with methane have been explored by FT‐ICR mass spectrometry and high‐level quantum‐chemical calculations. In contrast to the previously studied [FeO]+/CH4 and [OsO]+/CH4 couples, which undergo oxygen/hydrogen atom transfers and dehydrogenation, respectively, the [RuO]+/CH4 system produces selectively [Ru(CH)2]+ and H2O, albeit with much lower efficiency. Various mechanistic scenarios were uncovered, and the associated electronic origins were revealed by high‐level quantum‐chemical calculations. The reactivity differences observed for the [MO]+/CH4 couples (M=Fe, Ru, Os) are due to the subtle interplay of the spin–orbit coupling efficiency, orbital overlap, and relativistic effects.