Palladium(II) Complexes of the Thiosemicarbazone and N-Ethylthiosemicarbazone of 3-Hydroxypyridine-2-carbaldehyde:Synthesis,Properties,and X-Ray Crystal Structure

摘要

Two novel,stable Pd~(II) complexes,compounds 3 and 4,of two 3-hydroxypyridine-2-carbaldehyde thiosemicarbazones,1 and 2,resp.,were prepared from Li_2PdCl_4.The single-crystal X-ray structure of complex 3 (= [Pd(2)Cl]) shows that the ligand monoanion coordinates in a planar conformation to the metal via the pyridyl N-,the imine N-,and the thiolato S-atoms.Intermolecular H-bonds,pi-pi,and CH...pi interactions lead to a two-dimensional supramolecular assembly.The electronic,IR,UV/VIS,and NMR spectroscopic data of the two complexes are reported,together with their electrochemical properties.A sophisticated experimental procedure was used to determine the multiple dissociation constants of the ligands 1 and 2 by UV/VIS titration.