Synthesis, Structural Characterization and Properties of the Palladium(II) and Platinum(II) Complexes of 2-{2-[(pyridin-2-yl)aminomethylene]hydrazono}-thiazolidin-4-one and the 3-methyl Derivative

Reactions of N'-(4-oxothiazolidin-2-ylidene)picolinohydrazonamide (GAm4DHotaz, 1) and N'-(3-methyl-4-oxothiazolidin-2-ylidene)Picolinohydrazonamide (Am4Motaz, 2) with K-2[PdCl4] or K-2[PtCl4] afforded good yields of the complexes [Pd(Am4DHotaz)Cl]center dot 2H(2)O (3), [Pd(Am4DHotaz)Cl]center dot 1/2DMF (3a). [Pt(Am4DHotaz)Cl]center dot 3H(2)O (4). [Pd(Am4Motaz)Cl-2]center dot 0.5H(2)O (5). [Pt(Am4Motaz)Cl-2]center dot 5H2O (6), and [Pt(Am4Motaz)(2)]Cl-2 (6a). The crystal structures of the ligands 1 and 2, and of two of the complexes, 3a and 6a, have been studied by X-ray diffractometry. All of the new compounds were characterized by elemental analysis, mass spectrometry, IR and H-1 and C-13 NMR spectroscopy and, when pertinent and allowed by the solubility of the compounds, by Pt-195 NMR spectroscopy. In the square planar complexes of HAm4DHotaz, the ligand is bound to the metal atoms in an N,N,N-terdentate deprotonated coordination mode, whereas in the dicationic complexes of Am4Motaz, the metal atom is four-coordinated in a planar fashion by N,N atoms from two symmetry related ligands. Interesting intermolecular interactions were observed in the solid state in the ligands and complexes and these were based on hydrogen-bonding. In particular, complex 3a formed a pseudo-dimer, although the Pd-Pd distance between the two molecules is 3.360(1)angstrom, i.e. greater than the sum of van der Waal's radii.