Reactions at Lead ll Centers

Half-sandwich complexes of cobalt with intramolecular phosphorous coordination have been known for the cobalt atoms in oxidation state - -l and - -ll (see Sections 7.01.3.3 and 7.01.3.4). Butenschon has published a comprehensive review recently on cyclopentadienyl metal complexes bearing pendant phosphorous arsenic and sulphur ligands. Intramolecular coordination to the cobalt center via a substituted Cp ring also oecurred in a rare reaction which combined C-H and C-F activation at the same time, thus leading to the coupling between a pentafluorophenyl ring and a pentamethylcyclopentadienyl ring (see Scheme 10 above). 

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