Preparation and characterization of metal complexes containing a NS donor ligand derived from S-benzyldithiocarbazate and p-nitrobenzaldehyde. X-ray crystal structure of the nickel(II) chelate

Summary A series of metal (Cu, Ni, Zn, Cd and Pd) complexes of a Schiff base ligand derived from S-benzyldithiocarbazate and p-nitrobenzaldehyde were prepared and characterized. The Schiff base acts as a single negatively-charged bidentate ligand forming stable neutral metal complexes. Magnetic and spectroscopic data suggest a square planar structure for the Cu^II, Ni^II and Pd^II chelates. Single X-ray diffraction analysis of the Ni^II chelate established that the Schiff base loses a proton from its tautomeric thiol form and coordinates to the metal via the thiolato sulfur and -nitrogen. The geometry around Ni^II is square planar with two equivalent Ni-N and Ni-S bonds; the two nitrobenzyl rings and the coordination plane are almost isoplanar, giving a delocalized electronic system.