Formation of hydroxo-bridged copper(II) complexes by aeration of metallic copper

Abstract

When air is bubbled into an aqueous suspension of metallic copper in the presence of a chelate such as 1,10-phenanthroline (phen) and 2,2'- bipyridine (bpy), the copper dissolves and binuclear hydroxo- bridged complexes such as

                                     OH                          [(chel)Cu      Cu(chel)]X₂,xH₂O                                      OH

are formed (chel = chelate; 2X = CO₃^2-, X = ClO₄^- and Cl^-).

The dichlorides of such binuclear complexes have been prepared previously by aeration of freshly precipitated suspensions of CuCl. In the case of glycine, however, only the bis(glycinato)copper(II) complex is formed from metallic copper.    

These observations afford some evidence for the production of free radicals such as ^·OH and may be relevant to the mechanism of action of both the copper i.u.d, and the 'copper bracelet'.