Metallocycles cobalt

A hexanuclear cobalt(II) metallocrown has been reported by Thornton and co-workers 166). Reaction of Na(OMe) with cobalt(II) acetate and Hmhp in MeOH apparently gives [Co6Na(mhp)i2]" ", and anion was not located in a highly disordered crystal structure. A 5deld is not reported, and crystallization required a period of months. The structure contains six tetrahedral Co(ll) centers, each bound to two N and two O donors from pyridonate ligands. Six of these oxygen atoms lie within the metallocycle, and form an ideal cavity for coordination of sodium. 

In 1985 both Magnus and Schore independently proposed identical mechanisms based on stereochemical and regiochemical preferences observed in the product. Magnus s hypothesis was based on the stereochemical results for an intramolecular cyclization. He proposed that the product arose from formation of a metallocycle intermediate 7 or 8, carbon monoxide insertion to give 9, acyl migration fi om cobalt to carbon and reductive elimination of cobalt to form 10. The relative thermodynamic stability of the metallocycles 7 and 8 controlled the final product ratio. In the... 

Catalytic amounts of cobalt halides react with methyl lithium and tominal aliphatic epoxides to produce methyl ketones and alcohols. The thermochemistry and structures of the metallocycle and metal alkene isomers of formula Co(C3H6) from reaction of gaseous Co and propene or cyclopropane in a flow system have been studied. ... 

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