Aqua[bis(salicylidene)ethylenediaminato](isobutyl)cobalt(III)

The title B₁₂ model compound, {2,2′-[1,2-ethanediylbis(nitrilomethylidyne)]diphenolato-N,N′,O,O′}(isobutyl)cobalt(III), [Co(C₄H₉)(C₁₆H₁₄N₂O₂)(H₂O)], has distorted octahedral stereochemistry around the Co^III ion. The equatorial salen ligand displays a `stepped' conformation, which is the prefered conformation in penta- and hexacoordinate organocobalt-salen complexes. The axial Co—C bond length is close to that of coenzyme B₁₂ and in accordance with that of other B₁₂ models, but the difference in the axial Co—O bond length as well as the deviation from the ideal tetrahedral value of the Co—C—C angle are due to the trans influence of the axial isobutyl group, which has stronger σ-donor power.

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