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 Cu-II and Ni-II 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 Co-II/Co-III complexes of the polymeric ligand were obtained in which two molecules of the linear polymeric ligand trapped two cobalt ions (Co-II and Co-III) in each monomeric unit. These structures are very interesting in that they contain Co-II/Co-III, side by side, as high-spin square planar coordinated Coll ions and low-spin (diamagnetic) octahedral coordinated Co-III 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). (c) 2007 Wiley Periodicals, Inc.