As part of a study of metal ion effects on chemical transformations of nitrogen-containing agrochemicals, conversion of daminozide to succinate via cleavage of the hydrazide C-N bond was examined in the presence and absence of divalent metal ions. No conversion was observed in metal ion-free solutions or in the presence of 1.0 mM Ni-II, Zn-II, and Pb-II. Cu-II, in contrast, markedly increased rates of daminozide to succinate conversion. Halide ions (Cl-, Br-) had no effect on daminozide conversion in the absence of metal ions but markedly increased conversion rates observed in the presence of Cull, The nitrogen-donor ligands ethylenediamine, N-(2-hydroxyethyl)ethylenediamine, and 1,4,7,10-tetraazacyclododecane decreased rates of Cu-II-facilitated conversion, while 1,5,9-triazacyclododecane actually increased rates of conversion. H NMR and UV spectroscopy provide evidence for the formation of 1:1 Cu-II-daminozide complexes. Halide ion effects and nitrogen-donor ligand effects point to an oxidative mechanism for Cu-II-facilitated daminozide breakdown, rather than hydrolysis. The structurally related compound butyric acid 2,2-dimethylhydrazide (BH) is subject to the same Cu-II-facilitated breakdown via an oxidative mechanism. N,N-Dimethylsuccinamic acid (SA), in contrast, breaks down via a hydrolytic mechanism