Arquitecturas metalosupramoleculares funcionales derivadas de tiosemicarbazona

Resumo

Eleven ligands derived from mono-, bis- and tristhiosemicarbazone were designed and synthesized. These ligands exhibit different number of donor atoms, terminal substituents in the thiosemicarbazone strands or central linkers. The electrochemical oxidation of a metal anode (Mn, Fe, Co, Ni, Cu, Ag, Zn, Cd, Sn and Pb) in the presence of the ligand in an organic solvent has been used as an efficient method to stabilize neutral thiosemicarbazone complexes. The complexes obtained exhibit a wide number of self-assembled architectures, such as mesocates, dihelicates or cluster helicates. The tyrosinase behaviour of a Cu(I) cluster helicate in the presence of molecular oxygen was analyzed. Kinetic and mechanistic studies confirmed the catalytic behaviour of this system, as the thiosemicarbazone skeleton experiences an arene hydroxylation process. Silver, cadmium and lead complexes were studied by multinuclear NMR with the aim to establish correlations between the coordination environments in both solid state and solution. A bisthiosemicarbazone ligand and its manganese and zinc complexes were studied as anion sensors.