The Versatile Chemistry of Aryl Substituted 1,2,4-triazole Ligands in Molecular Magnetism

Abstract

The work presented in this thesis focuses on exploring the versatile chemistry of 4-aryl substituted 1,2,4-triazole derivatives. The ligands 4-(4'-nitrophenyl)-1,2,4-triazole (npt) and 4-(4'-carboxyphenyl)-1,2,4-triazole (Hcpt) were prepared following a modified known synthetic strategy. Reaction of either of these ligands with transition metal or lanthanide precursor salts resulted in two novel complexes, namely [FeII3(npt) 6(EtOH)4(H2O)2](ptol)6·4(EtOH) (1) and [DyIII4(mu3-OH) 2(mu3-O)2(cpt)6(MeOH)6(H 2O)]2·15,(MeOH) (5), and of five analogous compounds. In the case of 1, the structural analyses and the magnetic properties indicated that the complex consisted of a linear trinuclear Spin Crossover FeII compound with a T1/2 of 148 K. For this complex, the SC-XRD analyses were performed at 100 and 181 K in order to characterize the structural changes occurring during the spin transition. For 5, the magnetic and structural data indicated that the complex was a dumbbell-shaped cubane dimer {DyIII 4}2 for which each cubane unit is a Single-Molecule Magnet with a small effective energy barrier.