Palladium(II) complexes of 4-formylantipyrine N(3)-substituted thiosemicarbazones:: first example of X-ray crystal structure and description of bonding properties

Reaction of 4-formylantipyrine with thiosemicarbazide, N(3)-methylthiosemicarbazide and N(3)-ethylthiosemicarbazide produced the expected thiosemicarbazones, 1, 2 and 3. The three thiosemicarbazones were then reacted with K2PdCl4 to produce [Pd(NS)(2)] complexes, 4, 5, and 6, respectively, with coordination by the imine nitrogen and thiolate sulfur of the anionic thiosemicarbazone moiety. The thiosemicarbazones and their palladium complexes have been characterized by spectral IR, UV-Vis and H-1, C-13 NMR and electrochemical techniques. The crystal structure of 6 has been obtained and found to be highly symmetrical with a trans arrangement of the two bidentate ligands. (K) (C) 2003 Elsevier Science B.V. All rights reserved.