A Copper Complex of an Unusual Hydroxy-Carboxylate Ligand: [Cu(bpy)(c4h4o6)]

A copper(II) complex, (2,2'-bipyridine-kappa N-2,N')[2-hydroxy-2-(hydroxymethyl-kappa O)propanedioato-kappa O-2(1),O-3]copper(II), [Cu(C4H4O6)(C10H8N2)], containing the unusual anionic chelating ligand 2-(hydroxymethyl)tartronate, has been synthesized. [Cu(bpy)(2)(NO3)](NO3) was mixed with ascorbic acid and Dabco (1,4-diazabicyclo[2.2.2]octane) in DMF (dimethylformamide) solution in the presence of air to produce the title compound. The structure consists of square-pyramidal complexes that are joined by Cu center dot center dot center dot O contacts [2.703 (2) angstrom] into centrosymmetric dimers. The C4H4O62- ligand, which occupies three coordination sites at Cu, has previously been identified as an oxidation product of ascorbate ion.