Structural and Spectral Studies of Palladium (II) Complexes of Pyridil bis{3-Piperidyl-, bis{Hexamethyleneiminyl-, bis{N(4)-Diethyl- and bis{N(4)-Dipropylthiosemicarbazone}

Pyridil bis{N(4)-substituted thiosemicarbazones}, in which the substituents replacing the NH2 group on the thiosemicarbazone moieties are piperidyl, H2Plpip; hexamethyleneiminyl, H2Plhexim; diethylamino, H2Pl4DE; and dipropylamino, H2PI4 DP, have been synthesized. Representative palladium(II) complexes of these bis (thiosemicarbazones) have been characterized by IR, electronic, mass, and 1H and 13C NMR spectroscopy. Crystal structures have been determined for H2Plhexim and two of its palladium(II) complexes. H2Plhexim is in the Z isomeric form with intramolecular hydrogen bonding from both thiosemicarbazone moieties to pyridine nitrogens. [Pd(Plhexim)] has square-planar N2S2 coordination (i.e., imine nitrogen and thiolato sulfur atoms). [Pd2 (Plhexim)Cl2 · DMSO has two PdNNSCl centers with the pyridine nitrogen, imine nitrogen or hydrazinic nitrogen and thiolato sulfur atoms coordinated