Synthesis And Properties Research Of Novel Multifunctional Single-Molecule Magnets

Single-molecule magnets (SMMs) continue to be studied intensively in Chemistry, Physics and Material Science. SMMs refer to the magnetic clusters formed through the self-assembling of spin carriers and bridging ligands. Sizes of such molecules are in nanoscale, as a result, they perform both magnetic hysteresis as traditional magnets and quantum tunneling of the magnetization (QTM) and slow relaxation process. These properties make SMMs very promising candidates for applications in molecular spintronics high density data storage devices and quantum information processing.The unique magnetic features of SMMs come from the molecules themselves, rather than the long-range ordering. In order to develop suitable materials for applications, a key step is to organize the SMM molecules so that they can be separated individually, or in a very small number. To achieve this goal, strategies have included deposition in Langmuir-Blodgett films, incorporation inmesoporous silica, or encapsulation within carbon nanotubes. In these "up to down" methods, distribution of molecules is restrained by properties of the host.Here, we applied a "down to up" strategy to enclose single cation SMM molecules [Ln(W5O18)2]-9 (Ln=Ho, Er, Tb, Dy) as template within the cavities of discrete supramolecular silver(I) alkynyl clusters. As a result, we got a series of "peanut" shaped supramolecular clusters as [Ag42Ho(W5O18)2(tBuC=C)28Cl4]OH(1)、 [Ag42Er(W5O18)2(tBuC=C)28Cl4]OH(2)、[Ag42Tb(W5O18)2(tBuC=C)28Cl4]OH(3) and [Ag42Dy(W5O18)2(tBuC=C)28Cl4]OH(4). Components and structures of these clusters were thoroughly characterized. Researches of magnetic properties showed that SMM features had not only been maintained after encapsulation, but also the energy barrier of Er based SMM had been raised dramatically.Besides, we sought to synthesize high dimensional compounds using imadazole、 dithienylethene based ligands with paramagnetic transition metal ions to make multifunctional single-molecule magnets combining photochromic and magnetic properties. This part of work was still undergoing.