The inhibiting activity of thirteen nitrogen and sulfur compounds (ligands, L) in the presence of lead(H) diethyldithiocarbamate (Pb(dtc)(2)) (1 : 1) in the initiated oxidation of ethylbenzene with oxygen at 75 degrees C was studied. Six ligands and Pb(dtc)2 inhibit ethylbenzene oxidation when used individually. The joint use of antioxidants in two out of thirteen cases leads to the enhancement of the inhibiting activity of a pair as compared to that predicted by the rule of mixtures. The formation of new lead(H) complexes ([Pb(dtc)2 Q) was revealed in ethylbenzene, chloroform, and acetonitrile solutions by UV-visible spectrophotometry and anodic polarography for all the L + Pb(dtc)(2) pairs due to the coordination of a ligand donor atom to the metal. In the cases of enhancement of the antioxidant activity of the ligands when they were used in combination with Pd(dtc)(2) (1 : 1), the specificity of the ligand structure was established. This is very important for the selection of inhibiting ligand + metal complex pairs. The tentative structure and parameters of the chelate center of the [Pb(dtc)(2) L RO2 center dot] were given.