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An Iron Complex with a Bent, O‐Coordinated CO 2 Ligand Discovered by Femtosecond Mid‐Infrared Spectroscopy
Author(s) -
Straub Steffen,
Brünker Paul,
Lindner Jörg,
Vöhringer Peter
Publication year - 2018
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201800672
Subject(s) - femtosecond , spectroscopy , femtochemistry , chemistry , photochemistry , ligand (biochemistry) , bent molecular geometry , infrared spectroscopy , infrared , molecule , aqueous solution , laser , organic chemistry , optics , biochemistry , physics , receptor , quantum mechanics
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 CO 2 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 CO 2 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 CO 2 , which is end‐on‐coordinated to the metal center by one of its two oxygen atoms.