스포츠 토토 판매점/BK21 Colloquium

Molecular Nano스포츠 토토 판매점 Systems Exhibiting Exotic 스포츠 토토 판매점 Properties

연사: 홍창섭[고려대]

일시: 2007 년 5 월 18 일 오후 3시

장소: 무은재 기념관 307호 (멀티미디어 강의실)

ABSTRACT:

The research on single-molecule magnets (SMMs) and singe-chain magnets (SCMs) has attracted intensive attention due to intriguing physical properties associated with quantum tunnelling of magnetization effects within double energy well and potential applications to high-density information storage. Since the slow magnetization relaxation in [Mn12O12(CH3COO)16(H2O)4] (Mn12ac) was discovered much effort has been made to fabricate metal-oxo clusters with the aim of generating analogous properties to the archetype Mn12 cluster. Recently, a giant Mn84 cluster with a diameter of ~4 nm was characterized structurally and 스포츠 토토 판매점ally, exhibiting SMM behaviour. Despite the high nuclearity in the Mn84 supramolecular nanotube its ground state (S) and energy barrier (U) remain relatively small compared with the Mn12ac cluster.

To design such systems it would be beneficial if a bridging ligand has structural and 스포츠 토토 판매점 predictabilities. Cyanide is one of the good candidates as a bridge for 스포츠 토토 판매점 entities since it links para스포츠 토토 판매점 centers in a linear fashion and the 스포츠 토토 판매점 nature of compounds bridged by cyanides is dependent on 스포츠 토토 판매점 orbitals of metal constituents. Cyanide-linked 스포츠 토토 판매점 systems have successfully realized a variety of structures from zero-dimensional (0D) to 3D networks with intriguing multifunctional properties. Recently, because of increasing interests in isolated anisotropic systems, main emphasis has been on fabricating discrete or 1D systems to employ molecular precursors with ample coordinating capability, for instance, [M(CN)p]n- (p = 6, 8), and their counterparts having specific vacant sites or labile leaving ligands, [M’LxL’y]m+ (L = polydentate ligand, L’ = labile group). Another reliable strategy to this aim has been launched by engaging blocked cyanide-based building bricks for low-dimensional materials. The molecular building units with the 3d metal ions, [M(CN)pLq]n- (M = CrIII, FeIII), have been thoroughly investigated, while examples, [M(CN)pLq]n- (M = MoIII, ReII), which incorporate 4d or 5d metal ions into molecular precursors are still rare to date although the 4d or 5d 스포츠 토토 판매점 orbitals mediate stronger 스포츠 토토 판매점 couplings because they are more diffuse than the 3d 스포츠 토토 판매점 orbitals. In this talk, new cyanide-based SMMs and SCMs containing diverse spin sources will be introduced in terms of their structures and intriguing 스포츠 토토 판매점 properties.

문의처: 지승훈(054-279-2094, jhish@postech.ac.kr)