3-Ketoglutarates: Compounds with Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Mg, and Na

Abstract

Where A designates the dinegative 3-ketoglutarate ion and L indicates a trinegative species (likely the enolate ion), the following compounds have been obtained: Na2A, NaCuL.XH2O, MgA.XH2O, MnA.XH2O, CoA.XH2O, NiA.XH2O. Hydration numbers are uncertain. Stoichiometry of Cu(II) and Zn(II) compounds could not be established. Structures have been assigned on the basis of the infrared spectra. Na2A appears to be a simple ionic carboxylate. MgA, MnA, CoA, and NiA are assigned a similar structure, with unidentate carboxylate coordination and hydrogen-bonded coordination between the metal and the second carboxylate oxygen (through water). NaCuL is assigned a metal-bridged polymer structure. There is not significant metal interaction with the carbonyl oxygen in any of the proposed structures.