Synthesis, Structure And Magnetic Properties Of Triazenes Transition Metal Polynuclear Complexes

Considerable efforts were being undertaken to generate polynuclear complexes due to the intriguing structural diversities and the potential applications of polynuclear complexes in optics, electrochemistry, magnetism and various advanced materials. The design and synthesis of new ligands that supported transition metal complexes were often inspired by systems in bioinorganic, materials, and catalysis chemistry. By designing the appropriate ligand, we could chelate metal centers in special frame and control the electron withdrawal from the metal ion core, thereby modifying the intramolecular exchange interactions. The use of different bridging and polydentate ligands had afforded an impressive array of nuclear coordination complexes with new architectures. Among them, the triazenide groups had attracted our attention, as these compounds could serve as a monodentate, a bidentate chelating and bridging ligands. During the last two decades, the complexes with 1,3-(aryl) triazines have been investigated well. However, relatively few other triazenide complexes have been developed. Recently, triazenide with metallic have been developed by a three-core 12-ring complex. However the reports of triazenide polynuclear complexes with transition metals were rare. With this mind, we extended our interests to the design, synthesis and the reactivity with transition metals of new triazenide ligands.This paper described the design and synthesis of 7 heterocyclic triazenide ligands, which were as the building polynuclear complexes constructed primitives, choosed a variety of transition metal ions (Cu²⁺, Co²⁺, Ni²⁺) and different little ligands (Cl^-, Br^-, OAC^-) and used the method of room temperature volatilization to give 19 polynuclear complexes which were characterized by crystal structures and magnetic properties. The influences of reaction conditions, solvents and ratios on the structure and magnetic properties of producets were systematically discussed. This paper included four aspects as following:1. Two triazenide ligands were synthesized from methyl anthranilate or ethyl anthranilate with 2 - aminopyridine. The ligands reacted with different copper salts in different solvents to give different products. The results showed steric effect and little ligands, which acted as a coordination agent could have influence on the structure and magnetic properties of the products. The complex bridged by acetate showed strong antiferromagnetic because of the large angles of Cu-O-Cu.2. Two triazenide ligands containing o-anisidine were synthesized. The ligands reacted with transition metal ions (Cu²⁺, Co²⁺, Ni²⁺) to give 4 polynuclear complexes. Experimental results showed that the anions (Cl^-, Br^-, ClO4^-, OAC^-) were not involved in the reaction.3. Two triazenide ligands were synthesized from methyl anthranilate or ethyl anthranilate with 2^-aminothiazole. Different products were abtained by changing the solvents of reactions carried out on Cu²⁺ and Cu+. The results showed that, in these systems, the transesterification was found. This could be the metal ions and Et₃N play an important role in the transesterification.4. A symmetrical triazenide ligand-bis[benzothiazole] triazene was synthesized, which had five potential N atoms, might have important use in polynuclear complexes in future.