Highly Efficient Reversible Hydrogenation of Carbon Dioxide to Formates Using a Ruthenium PNP-Pincer Catalyst

Authors

  • Georgy A. Filonenko,

    1. Inorganic Materials Chemistry group Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (The Netherlands)
    2. Institute for Complex Molecular Systems (ICMS), Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (The Netherlands)
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  • Robbert van Putten,

    1. Inorganic Materials Chemistry group Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (The Netherlands)
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  • Erik N. Schulpen,

    1. Inorganic Materials Chemistry group Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (The Netherlands)
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  • Prof. Dr. Emiel J. M. Hensen,

    1. Inorganic Materials Chemistry group Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (The Netherlands)
    2. Institute for Complex Molecular Systems (ICMS), Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (The Netherlands)
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  • Dr. Evgeny A. Pidko

    Corresponding author
    1. Inorganic Materials Chemistry group Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (The Netherlands)
    2. Institute for Complex Molecular Systems (ICMS), Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (The Netherlands)
    • Inorganic Materials Chemistry group Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (The Netherlands)===

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Abstract

The front cover artwork for Issue 6/2014 is provided by the research group of Inorganic Materials Chemistry and the Institute for Complex Molecular Systems, Eindhoven University of Technology (The Netherlands). The image shows a concept of a hydrogen battery in which H2 storage and its release are achieved through reversible hydrogenation of CO2 catalysed by an Ru-PNP pincer complex. See the Communication itself at http://dx.doi.org/10.1002/cctc.201402119.

What is the most significant result of this study?

1234We developed a robust and highly active homogeneous catalytic system based on an Ru-PNP pincer complex for reversible hydrogenation of CO2, which enables H2 storage in formic acid and its release in the reversed mode. This new system offers an improvement on the current state-of-the-art.

Scheme 1.

From left to right: Robbert van Putten, Erik N. Schulpen, Georgy A. Filonenko

Scheme 2.

Prof. Dr. Emiel J. M. Hensen

Scheme 3.

Dr. Evgeny A. Pidko

Scheme 4.

Inorganic Materials Chemistry group and Institute for Complex Molecular Systems Eindhoven University of Technology P.O. Box 513, 5600 MB Eindhoven (The Netherlands) E-mail: e.a.pidko@tue.nl

What was the biggest surprise on the way to the results?

Although the importance of the strength of the base promoter in catalytic CO2 hydrogenation is well known, it came as a surprise that varying the base strength also caused a change in the rate-determining step in the reaction mechanism.

What aspect of this project do you find most exciting?

The reaction between two small molecules, CO2 and H2, looks quite simple on paper. Yet, Ru-PNP and other efficient catalysts such as the famous Nozaki and Fujita systems promote this reaction in a complex manner: besides the metal centre, the ligand and other components of the reaction medium participate in the catalysis. We can now begin to understand the complexity of the underlying chemical transformations, which allows future improvements in performance.

Is your current research mainly fundamental or applied?

While our research is mostly fundamental in nature, it has a clear outlook on application. Developing a molecular description of catalysis enables the formulation of guiding principles for improved and novel catalysts for specific chemical transformations. The present work is an illustrative example of this approach. The foundation for these advances came forth from our earlier mostly theoretical study (ACS Catal.­ 2013, 3, 2522).

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Acknowledgements

E.A.P. gratefully acknowledges the Technology Foundation STW and the Netherlands Organization for Scientific Research (NWO) for his personal VENI grant. We thank ICMS Animation Studio for their help in creating the cover illustration.

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