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

The title B-12 model compound, aqua{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 preferred conformation in penta- and hexacoordinate organocobalt-salen complexes, The axial Co-C bond length is close to that of coenzyme B-12 and in accordance with those of other B-12 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 sigma-donor power.