O-2(-) SCAVENGER PROPERTIES OF COPPER(II) COMPLEXES WITH DIAMINO-DIAMIDE-TYPE LIGANDS

Copper(II) complexes with diamino-diamido-type ligands were tested as catalysts of O-2(-) dismutation. ESR spectra of these systems showed t hat, in consequence of the O-2(-) interaction, all the bis complexes o f formula [Cu(L)(2)H--2] (where L = L-valylamide, L-phenylalanylamide, L-prolylamide) transformed into [Cu(L)H--1(OH)(2)] species. They also showed the highest scavenger as well as catalytic activity. The compl ex species formed after the interaction continued to show scavenger ac tivity also. Stronger copper(II) complexes hardly interacted and showe d scarce scavenger properties. In the series of [Cu(L')H--2] complex s pecies (where L' = (S,S)N,N'-bis(phenylalanyl)1,2-ethanediamine and -1 ,3-propanediamine and (S,S)N,N'-bis(prolyl)-1,2-ethanediamine) the att empt to correlate catalytic activity with structural features revealed that a longer methylene chain could become a critical factor.