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Chromium: Organometallic Chemistry

  1. Klaus H. Theopold,
  2. Robin R. Kucharczyk

Published Online: 15 DEC 2011

DOI: 10.1002/9781119951438.eibc0042

Encyclopedia of Inorganic and Bioinorganic Chemistry

Encyclopedia of Inorganic and Bioinorganic Chemistry

How to Cite

Theopold, K. H. and Kucharczyk, R. R. 2011. Chromium: Organometallic Chemistry. Encyclopedia of Inorganic and Bioinorganic Chemistry. .

Author Information

  1. University of Delaware, Newark, DE, USA

Publication History

  1. Published Online: 15 DEC 2011

Abstract

Starting with Hein's investigation of the reaction of CrCl3 with PhMgBr in the beginning of the twentieth century, chromium organometallic chemistry is now marked by an ever increasing diversity of compound types and formal oxidation states. Organochromium compounds such as Cr(CO)6, (η6-C6C6)2Cr, and (OC)5Cr[DOUBLE BOND]C(OMe)Ph represent milestones in the development of organometallic chemistry as a whole. The lower oxidation states (−IV to +II) are dominated by chromium carbonyl complexes with 18 electron configurations, while midvalent compounds (+II, +III) often feature cyclopentadienyl rings and exhibit unpaired electrons. Organometallic compounds of chromium in its highest oxidation states (+IV to +VI) are still relatively rare, but this has been a growing area of late. Much of the interest in chromium alkyls is due to the metal's important role in the catalysis of olefin polymerization. Homogeneous model systems for the Union Carbide catalyst (Cp2Cr/SiO2) and the Phillips catalyst (CrO3/SiO2) still motivate much synthetic work. Applications of organochromium chemistry in organic synthesis are also becoming more numerous and useful.

Keywords:

  • carbonyls;
  • arene complexes;
  • chromocene;
  • carbenes;
  • carbynes;
  • alkyls;
  • olefin polymerization;
  • catalysis;
  • paramagnetism