The pH-dependence of the EPR spectra of a newly synthesized imidazolate-bri
dged Cu(II)-Zn(II) complex, [(dien)Cu(im)Zn(dien)](3+) (dien = diethylenetr
iamine, im = imidazolate anion), has been studied in frozen solution (50% D
MSO) to explore the mode of breaking of the imidazolate bridge. The data su
ggest that the imidazolate bridge in the complex is stable only at high pH
(>9) and breaks on the zinc side at lower pH values.