S-oxygenation of dithiocarbamate (DTC) complexes has been implicated in their function as industrial anti-oxidants, as well as in their use as pesticides and most recently in their cumulative toxicity, but little is known of the species generated. Several S-oxygenated derivatives of N, N-disubstituted DTCs have been synthesized, characterized by a variety of methods, and their structure and reactivity examined. Low-temperature reaction of bis(N,N-diethyldithiocarbamato) zinc(II), Zn(deDTC)(2) 1, with oxygenating reagents (hydrogen peroxide, m-chloroperbenzoic acid, urea hydrogen peroxide) yields mono-oxygenated DTC complexes (N, N-peroxydiethyldithiocarbamato)(N,N-diethyldithiocarbamato) zin(II), Zn(O-deDTC)(deDTC), 2 and bis(N, N-peroxydiethyldithiocarbamato) zinc(II), Zn(OdeDTC)(2), 3. The tetraoxygenated derivative bis(N, N-diethylthiocarbamoylsulfinato) zinc(II), Zn(O-2-deDTC)(2), 4, was cleanly obtained by initial reaction of the DTC salts with stoichiometric oxidant prior to complexation with Zn( II). X-ray crystallographic analysis of 2, 3, and 4 show that the peroxydithiocarbamate ligands are S, O-bound. Similar derivatives were obtained from the homoleptic dimethyl and pyrollidine DTC Zn complexes. These oxygenated species display unique H-1 and C-13 NMR variable-temperature spectra, as the symmetry of DTC ligand is broken upon oxygenation; total line shape analysis (TLSA) was used to compare the energetic parameters for rotation about the C-N bond in several derivatives. Compounds 2, 3, and 4 were deoxygenated by alkyl phosphine, regenerating the parent dithiocarbamate 1. The peroxydithiocarbamate complexes were susceptible to base-catalyzed hydrolytic decomposition, giving ligand-based products indicative of S-oxidation and S-extrusion.