Nickel(II) and iron(III) complexes of a diamide derivative of the hexadentate complexone trans-1,2-diaminocyclohexane-tetraacetic acid

The diacid/diamide derivative trans-1,2-bis{carboxymethyl-[2-(2,3-dihydro-indol-1-yl)-2-oxoethyl]-amino}-cyclohexane (H2L) of the hexadentate complexone ligand trans-1,2-diaminocyclohexane-tetraacetic acid, and its nickel(II) and iron(III) complexes have been prepared. The nickel(II) complex [NiL] has a distorted octahedral geometry and the iron(III) complex [FeL(H2O)][NO3] has a seventh ligand (water), to give a distorted pentagonal bipyramidal geometry.