BINUCLEAR MACROCYCLIC AND MACROBICYCLIC COMPLEXES FOR DIOXYGEN ACTIVATION AND TRANSPORT

The binuclear cobalt(II) complexes of OBISTREN and OBISDIEN are excell ent oxygen carriers because their dioxygen complexes do not undergo li gand degradation and can give up their coordinated oxygen when subject ed to a change of pressure or temperature. The additional coordination positions in OBISIDIEN recognize and coordinate bridging reducing lig ands which thin undergo redox reactions with coordinated dioxygen. Whe n isophphalaldehyde condenses with diethylenetriamine, the resulting S chiff base macrocyclic ligand forms a binuclear Cu(I) complex which re acts with dioxygen to form a complex which rapidly hydroxylates an adj acent phenyl ring. When furan or pyridine is used in place of benzene the resulting dioxygen complexes may be used to oxidize substrates suc h as phenols, catechols, and aromatic amines. A catalytic cycle for th e oxidation of 3,5-ditertiarybutylcatechol is shown.