Copper Complexes of Thiosemicarbazone−Pyridylhydrazine (THYNIC) Hybrid Ligands:  A New Versatile Potential Bifunctional Chelator for Copper Radiopharmaceuticals

Two new thiosemicarbazone−pyridylhydrazine (THYNIC) hybrid ligands have been synthesized. Copper(II) and copper(I) complexes of the ligands have been prepared and characterized by X-ray crystallography. Cyclic voltammetry measurements show that the copper(II) complexes undergo quasi-reversible reductions at biologically accessible potentials. One of the ligands, bearing a pendant carboxylate arm, has been conjugated to <i>N</i>-α-(<i>tert</i>-butoxycarbonyl)-l-lysine.