A copper complex of an unusual hydroxy–carboxylate ligand: [Cu(bpy)(C₄H₄O₆)]

Abstract

A copper(II) complex, (2,2′-bipyridine-κ2 N,N′)[2-hydroxy-2-(hydroxymethyl-κO)propanedioato-κ2 O 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...O contacts [2.703 (2) Å] into centrosymmetric dimers. The C4H4O6 2− ligand, which occupies three coordination sites at Cu, has previously been identified as an oxidation product of ascorbate ion.