The Electronic Ground State of [Fe(CO)3(NO)]−: A Spectroscopic and Theoretical Study

• Published in: Angewandte Chemie (International ed.) Vol. 53; no. 7; pp. 1790 - 1794
• Main Authors: Klein, Johannes E. M. N., Miehlich, Burkhard, Holzwarth, Michael S., Bauer, Matthias, Milek, Magdalena, Khusniyarov, Marat M., Knizia, Gerald, Werner, Hans-Joachim, Plietker, Bernd
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 10.02.2014; WILEY‐VCH Verlag; Wiley Subscription Services, Inc
• Edition: International ed. in English
• Subjects: electronic structure; Enemark-Feltham notation; ferrates; iron catalysis; spectroscopy; Enemark-Feltham notation; ferrates; iron catalysis; spectroscopy; electronic structure
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.201309767

During the past 10 years iron‐catalyzed reactions have become established in the field of organic synthesis. For example, the complex anion [Fe(CO)3(NO)]−, which was originally described by Hogsed and Hieber, shows catalytic activity in various organic reactions. This anion is commonly regarded as being isoelectronic with [Fe(CO)4]2−, which, however, shows poor catalytic activity. The spectroscopic and quantum chemical investigations presented herein reveal that the complex ferrate [Fe(CO)3(NO)]− cannot be regarded as a Fe−II species, but rather is predominantly a Fe0 species, in which the metal is covalently bonded to NO− by two π‐bonds. A metal–N σ‐bond is not observed. Even more complex: Spectroscopic and quantum chemical investigations show that the complex ferrate [Fe(CO)3(NO)]− cannot be considered to be a Fe−II species, but rather is predominantly an Fe0 species, in which the metal is covalent bound to NO− by two π bonds. A metalN σ bond is not observed.