Abstract A simple and easy preparation of the hydrogen oxalate ligand (HOOCCOO)−, with only one deprotonated carboxylic function, is described. 13 C NMR spectroscopy furnishes a straightforward characterization of this interesting ligand. This ligand coordinates in its monodeprotonated form to a Cu II complex with a free coordination position, yielding a complex that presents a very weak antiferromagnetic interaction. In a subsequent step, the ...
