The joint inhibiting effect of heavy metal N,N-diethyldithiocarbamates M(dtc)(n), where M = Cu(II), Co(III), or Pb(II), and three aromatic amines (1 : 1) in the initiated oxidation of ethylbenzene with oxygen at 75 degrees C has been examined. The synergistic inhibitory effect of 1 : 1 M(dtc)(n)-amine pairs strongly depends on the nature of the metal atom and the chelate unit structure of the metal dithiocarbamate. For most couples, the formation of new Cu(II), Co(III), and Pb(II) complexes of the [M(dtc)(n)-amine] type in chloroform via coordination of the amine donor atom to the metal has been proved spectrophotometrically. Possible routes of oxidation chain termination by the newly formed complexes have been established.