Magnetic Clusters Based On Schiff Base Ligand And Tripodal Alcohol Ligand: Syntheses And Characterization

Molecular magnetic materials are not only one kind of functional materials, but also a new interdiscipline of inorganic, organic, polymeric, and physical chemistry. Compared with traditional magnets which are atom based with d-(or f-) orbital-based spin sites and have extended network bonding in three dimensions, molecular magnetic materials are superior in many aspects, such as low density, flexibility, solubility, transport, tuning properties and so on. They have attracted much attention in recent years because of the meaningful contributory to magnetic theory and potential applications.Molecular magnetic materials include pure organic molecules, inorganic compounds, organic-inorganic hybrid materials, spin-crossover complexes (SCOs), single-molecular magnets (SMMs) and single-chain magnets (SCMs). High-spin molecules with easy-axis magnetic anisotropy show slow magnetic relaxation of spin-flipping along the axis of magnetic anisotropy and are called SMMs (cluster) or SCMs (chain). They behave as molecular size permanent magnets at low temperature and magnetic relaxation occurs by quantum tunneling processes. Such molecules are promising candidates for use in quantum devices. However, the critical temperature (7c) of both the existing SMMs and SCMs is too low to apply. It's nowadays the challenge to design and synthesize SMMs and SCMs with high Tc.In this paper, a survey on the development of molecular-based magnets is concisely presented along with the research significance. Based on the previous work, two organic ligands were designed to contact 3d-metal ions for the syntheses of high spin clusters. First, a O,N,N',O'-Schiff base ligand, N,N'-bi(salicylidene)-2,6-pyridinediamine (H2L1) was used to construct clusters with paramagnetic metal ions. We prepared a mesocate of Cu₂L¹₂ with the ligand adopting a cis, cis-conformation and a helicate of Co₃L¹₃ with the ligand adopting a cis, trans-conformation. Magnetic measurements reveal that both the two clusters display antiferromagnetic properties. Then the rational design of a ligand, 4-(tris(hydroxymethyl)methyl)pyridine, and the coordination reactions with 3d-metal ions has been outlined. Four complexes based on this tripodal alcohol ligand were prepared by solvothermal method and were partially characterized by IR and ICP atomic emission spectrometry.Besides the molecular-magnetic materials, two chiral porous MOFs constructed by chiral BINOL ligands and Cu^II ions were discussed in this paper.