Synthesis and characterization of a novel series of metallothiocarbohydrazone polymers and their adducts

A novel linear polymeric pentadentate (O2N2S‐sites) ligand (H3L) bearing both soft and hard donors was prepared by the reaction of a bifunctional carbonyl compound, 4,6‐diacetylresorcinol, with a bifunctional hydrazide compound, thiocarbohydrazide. Mono‐ and binuclear CuII and NiII complexes/each monomeric unit of the polymeric ligand were obtained depending on the pH of the reaction medium and the metal ion. Adducts with 1,10‐phenanthroline (Phen) and 2,2′‐bipyridyl (Bpy) were obtained. Anomalous dimeric CoII/CoIII complexes of the polymeric ligand were obtained in which two molecules of the linear polymeric ligand trapped two cobalt ions (CoII and CoIII) in each monomeric unit. These structures are very interesting in that they contain CoII/CoIII, side by side, as high‐spin square planar coordinated CoII ions and low‐spin (diamagnetic) octahedral coordinated CoIII ions. The suggested structures of the complexes have been elucidated on the basis of elemental and thermal analyses, conductance, and magnetic susceptibility measurements as well as spectral studies (electronic, IR, and ESR spectra).