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Updated: May 25, 2026
Heterogeneous Removal of Water-Soluble Ruthenium Olefin Metathesis Catalyst from Aqueous Media Via Host-Guest Interaction
Published on: August 23, 2018
Transient Ru-methyl formate intermediates generated with bifunctional transfer hydrogenation catalysts
Richard H Perry1, Kristen R Brownell, Konstantin Chingin
1Department of Chemistry, Stanford University, Stanford, CA 94305-5080, USA.
Desorption electrospray ionization mass spectrometry (DESI-MS) revealed transient ruthenium intermediates during transfer hydrogenation. These intermediates, incorporating methyl formate, suggest a competing oxidation pathway for methanol.
Area of Science:
- Organometallic Chemistry
- Catalysis
- Mass Spectrometry
Background:
- Ruthenium catalysts are crucial for transfer hydrogenation reactions.
- Understanding transient intermediates is key to optimizing catalytic processes.
- Methanol oxidation pathways in ruthenium catalysis are not fully elucidated.
Purpose of the Study:
- To investigate the reactivity of a (β-amino alcohol)(arene)RuCl catalytic precursor in methanol.
- To identify transient intermediates formed during the catalytic cycle using DESI-MS.
- To elucidate competing reaction pathways beyond hydrogen transfer.
Main Methods:
- Desorption electrospray ionization (DESI) coupled with high-resolution Orbitrap mass spectrometry (MS).
- Analysis of transient intermediates with millisecond lifetimes.
- Gas chromatography-MS and nuclear magnetic resonance spectroscopy for bulk reaction analysis.
Main Results:
- Two transient ruthenium intermediates (Ru(II) and Ru(IV)) incorporating methyl formate were detected.
- The Ru(IV) intermediate formation requires dissolved O(2), indicating an oxidation step.
- Methanol was confirmed to be oxidized to methyl formate, suggesting a competing pathway.
Conclusions:
- Transient species from the Ru(II) precursor can selectively oxidize methanol to methyl formate.
- A reaction pathway involving methanol oxidation competes with the primary hydrogen transfer cycle.
- DESI-MS enabled the identification of previously unrecognized intermediates and pathways in this catalytic system.
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