331821-76-2Relevant academic research and scientific papers
Nitrogen-functionalized cyclopentadienyl ligands with a rigid framework: Complexation behavior and properties of Cobalt(I), -(II), and -(III) half-sandwich complexes
Enders, Markus,Ludwig, Gunter,Pritzkow, Hans
, p. 827 - 833 (2008/10/08)
Reaction of 2-lithio-N,N-dimethylaniline with 2,3,4,5-tetramethylcyclopentenone yields 1-[2-(N,N-dimethylaminophenyl)]-2,3,4,5-tetramethylcyclopentadiene (2). As in 1-(8-quinolyl)-2,3,4,5-tetramethylcyclopentadiene (1), the N-donor is connected to the Cp ring by a rigid C2 spacer. Co2(CO)8 reacts with 1 or 2 to give the CoI-dicarbonyl half-sandwich complexes 7 and 3, respectively. Irradiation leads to the binuclear complexes 4 and 8 with a Co-Co double bond. Oxidation of 3 or 7a is possible with iodine. Whereas 7a directly forms the CoIII complex 9 with coordination of the quinoline to the metal, 3 yields the monocarbonyldiiodo complex 5. Upon gentle heating in dichloromethane, 5 loses carbon monoxide to give the cobalt complex 6, displaying intramolecular nitrogen coordination. Reaction of the dimethylaniline-substituted cyclopentadienide 10 with CoCl2 yields the CoII complex 11. The CoIII complex 6 and the CoII complex 11 were treated with methylaluminoxane (MAO) and gave low-activity catalysts for the polymerization of ethylene.
