An Iron Complex with a Bent,O‐Coordinated CO2 Ligand Discovered by Femtosecond Mid‐Infrared Spectroscopy |
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Authors: | Steffen Straub Paul Brünker Dr. Jörg Lindner Prof. Dr. Peter Vöhringer |
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Affiliation: | Institut für Physikalische und Theoretische Chemie, Rheinische Friedrich-Wilhelms-Universit?t, Bonn, Germany |
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Abstract: | The activation of carbon dioxide by transition metals is widely recognized as a key step for utilizing this greenhouse gas as a renewable feedstock for the sustainable production of fine chemicals. However, the dynamics of CO2 binding and unbinding to and from the ligand sphere of a metal have never been observed in the time domain. The ferrioxalate anion is used in aqueous solution as a unique model system for these dynamics and femtosecond UV‐pump mid‐infrared‐probe spectroscopy is applied to explore its photoinduced primary processes in a time‐resolved fashion. Following optical excitation, a neutral CO2 molecule is expelled from the complex within about 500 fs to generate a highly intriguing pentacoordinate ferrous dioxalate that carries a bent carbon dioxide radical anion ligand, that is, a reductively activated form of CO2, which is end‐on‐coordinated to the metal center by one of its two oxygen atoms. |
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Keywords: | CO2 activation femtochemistry photochemistry time-resolved IR spectroscopy transition-metal complexes |
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