CU(I) AND CU(II) DINUCLEAR COMPLEXES OF A NEW HEXAAZA SCHIFF-BASE DINUCLEATING MACROCYCLIC LIGAND AND THEIR OXYGENATION CHEMISTRY

A new macrocyclic hexaaza binucleating Schiff base ligand (32),2,11,13 (14),15,17(34),18,27,29(33),30-decaene (MX2DIPN2 or 1) has been prepar ed in good yield by direct condensation of m-phthalaldehyde and 3,3'-i minobis(propylamine). MX2DIPN2 forms a dinuclear Cu(I) complex that re acts with molecular oxygen to form [(MX2DIPN2)Cu-2(O-2)](2+). This oxy gen complex does not undergo intramolecular oxygen insertion into the phenyl ring in sharp contrast with its macrocyclic analog [(MX2DIEN2)C u-2(O-2)](2+) (MX2DIEN2 is the macrocyclic ligand formed by the conden sation of m-phthalaldehyde and diethylenetriamine), the result of the enlargement of the macrocyclic cavity. It has been shown that [(MX2DIP N2)Cu-2(O-2)](2+) is an efficient and selective catalyst for the oxida tion of 3,5-di-t-butylcatechol to 3,5-di-t-butyl-1,2-benzoquinone in t he presence of 1 atm O-2. Furthermore, the measured initial rate const ants reveal that it reacts much faster than any of the related macrocy clic systems reported to date. (C) 1998 Elsevier Science B.V.