The Stability of Fused Rings in Metal Chelates. III. The Relative Stability of Copper(II) Complexes of Aldehyde- and Ketone-Schiff Bases

The relationship between the structure of fused-ring systems and the relative stability of copper(II) Schiff base chelates has been discussed, on the basis of the properties of six copper(II) complexes, in connection with the transamination reaction. As the conclusion it has been suggested that the transamination reaction in fused-ring systems containing copper(II)-glyoxylate- or -pyruvate-Schiff bases may be expected only in such appropriately unstable systems as have two five-membered rings and that it is generally accompanied by a stabilization of the system. The preparation and properties of the two new copper(II) chelates, glyoxylidene-β-alaninatoaquo-copper(II) and pyruvidene-α-alaninatoaquocopper(II), have been described.