SYNTHESIS AND REACTIVITY OF DINUCLEAR COPPER-COMPLEXES HAVING A META-XYLYL SPACER BETWEEN COORDINATION UNITS

New hybrid ligands containing combinations of pyrazole, pyridine, and imidazole have been prepared, and the reaction chemistry of their copper(I) derivatives has been studied. The dinucleating ligands provide three nitrogen donors to each metal ion, and each coordination unit is separated by a m-xylyl group. Except for the case where four of the donor groups are pyridyl, in which the xylyl spacer is hydroxylated, all of the complexes react via four-electron reduction of the dioxygen molecule to give bis(mu-hydroxy)copper(II) dimers.