The Design And Preparation Of Molecule-based Magnet

Since the discovery of the first room-temperature molecular-based magnetic materials, it has attracted great attention and been widely studied both experimentally and theoretically. The organic magnetic materials have the advantage of the characteristics of structural diversities, low density, and readily processing in contrast to traditional magnetic materials, which fit to design and synthesize some functional material. Due to different kinds of magnetic center, the organic magnetic materials been separated into pure organic magnets, inorganic magnets, hybrid organic–inorganic magnets. For a molecular-based magnet, consisting of magnetic metal ions coordinated with nonmagnetic organic species, both the metal ions and the organic species contribute to the observed magnetism. The metal ions are the source of magnetic moments while the organic species provide superexchange pathways between the magnetic centers.We prepare inorganic magnets using transition metals coordinating with organic ligand, for example, Cu(H2EDTA)(H2O), Mn3(HEDTA)2·10H2O and Co2(C4H2O4)2·10H2O. We made investigations on the X-ray single-crystal structure, the infrared spectra (IR), thermogravimetric analysis (TG), superconducting quantum interference device detector (SQUID) and Electron paramagnetic resonance spectra (EPR) properties. The detailed magnetic ordering discussion reveals the antiferromagnetic interactions in the three complexes; simultaneously, we obtain satisfactory result with theoretically calculation. From the magnetic analysis of the three complexes and the similar complexes, it could be seen superexchange pathways may affect the magnetization greatly, so understanding the relationship between the crystal structure and magnetic ordering is helpful to design novel molecular-based magnetic compounds.