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Heteroatom‐Free Arene‐Cobalt and Arene‐Iron Catalysts for Hydrogenations
Author(s) -
Gärtner Dominik,
Welther Alice,
Rad Babak Rezaei,
Wolf Robert,
Jacobi von Wangelin Axel
Publication year - 2014
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.201308967
Subject(s) - heteroatom , chemistry , cobalt , alkene , catalysis , hydroformylation , anthracene , rhodium , homogeneous catalysis , organic chemistry , photochemistry , polymer chemistry , ring (chemistry)
Abstract 75 years after the discovery of hydroformylation, cobalt catalysts are now undergoing a renaissance in hydrogenation reactions. We have evaluated arene metalates in which the low‐valent metal species is—conceptually different from heteroatom‐based ligands—stabilized by π coordination to hydrocarbons. Potassium bis(anthracene)cobaltate 1 and ‐ferrate 2 can be viewed as synthetic precursors of quasi‐“naked” anionic metal species; their aggregation is effectively impeded by (labile) coordination to the various π acceptors present in the hydrogenation reactions of unsaturated molecules (alkenes, arenes, carbonyl compounds). Kinetic studies, NMR spectroscopy, and poisoning studies of alkene hydrogenations support the formation of a homogeneous catalyst derived from 1 which is stabilized by the coordination of alkenes. This catalyst concept complements the use of complexes with heteroatom donor ligands for reductive processes.