The reactivity of complexed carbocycles,part 9. New cyclononatetraene cobalt complexes(1)

Summary Two new C₅H₅CoC₉H₁₀ cobalt complexes were shown to contain the cyclononatetraene ligand coordinated in a (3–6-)- and in a (1–25-6-) fashion. The former complex (2) rearranges at elevated temperatures to the latter (3) in a novel type of isomerisation. Complex (3) can be protonated with strong acids and hydrogenated at the uncomplexed double bonds. All compounds were characterised by¹³C n.m.r. spectroscopy.