Reaction of K2[PdCl4] with N4-substituted thiosemicarbazones of 8-quinolinaldehyde (HLR) in water-dimethylformamide (DMF) solutions, gives rise to the formation of the complexes of the general formula [Pd(LR)Cl] where R is H (I), C2H5 (II) or C6H2(CH3)3 (III) and [Pd(LR)Cl]∙DMF (IV), where R is C6H5. The X-ray investigation of II – IV structure shows a tridentate coordination of the thiosemicarbazones via N,N,S set of donor atoms and the coordination number of the palladium is supplemented up to four by chlorine ion. The structure of the complexes II-IV is N,N,S,Cl square-planar. In the figure the structure of III is presented as an example.figureFig. Structure of the complex III (A), V (B) and VII (C) The ionic structure can be obtained when the chlorine anion is substituted by neutral thiourea molecule (Tu). After treatment of I with Tu and slow evaporation of waterdimethylformamide solutions a compound of the composition [Pd(LH)Tu]Cl∙DMF∙(V) were obtained. The X-ray investigation of the structure showed that the complex is formed by the cation [Pd(LH)(Tu)]+ , anions Cland solvating DMF molecule. The coordination mode of the thiosemicarbazone in these complexes is the same as was found in II-IV, but the fourth position in the square-planar coordination surrounding is occupied by the sulfur atom of the Tu molecule (Fig. B). Interaction of V with Ag2SO4 gives rise to the formation of [Pd(LH)Tu]2∙SO4∙2DMF (VI). The chlorine ion can be substituted from the inner sphere too. The treatment of II with KNCS in water-DMF solutions is accompanied by the dissolution of the products and precipitation after a slow vaporization of a compound of the formula Pd(LC2H5)NCS (VII). The complex Pd(L-C6H4(CH3))NCS∙H2O (VIII) was obtained in the same mode. The structures of the both complexes are molecular with a square-planar configuration formed by N,N,S donor set of the thiosemicarbazones and coordinated NCSanion. It is interesting to note that, nevertheless the palladium(II) ion is a thiophylic species, in these complexes the coordination of the NCS-ion via nitrogen atom is accepted (Fig. C). The common peculiarity of the complexes I-VIII is the stabilization of the anionic form of coordinated N4-substituted thiosemicarbazones of 8-quinolinaldehydes.