Development of Multi-functional Magnets Based on Supramolecular Architecture

超分子技术已被用于调整基于分子的磁性材料。我们已经开发了纳米多孔磁性材料，其磁性可以通过包裹小的抗磁性分子来改变。通过主客体化学的方法研究了可切换磁体。三和四自由基取代氮杂大环的主客体配合物提供了主体的折叠结构，其中自由基氧原子与客体金属离子配位，导致固相反铁磁耦合增强和溶液相ESR谱线加宽。我们还利用桥联配体作为超分子合成子制备了金属-自由基杂化磁体。开发了新型顺磁性配体(pzNN、pzIN、pzBisNN、pzbislN、6bpyNO和2pyNO)，并应用于单核、二核、三核和多核配合物(NN、IN和NO代表有机自由基团)的合成。我们开发了桥联顺磁配体(HIN、HNN、CnPNN)的潜在用途。在一维Co-C4PNN络合物中，单链磁体(SCM)具有很强的磁有序性，在6K时具有最大的矫顽场(52Koe(4.1mAm^-1))。几种寡核3D-4f异金属络合物被表征为研磨的亚铁磁性高自旋分子。由于稀土离子具有大的磁动量和各向异性，被认为是单分子磁体的候选元素。我们建立了[Dy_2Cu]，[Dy_4Cu]和[Dy_2，Cu2]配合物作为新的单分子磁体，[Dy_2，Cu2，]_n作为单分子磁体。首次提出了3D-4F异质金属SMM和SCM之间的磁化量子隧穿机制。

Supramolecular techniques have been used to tune molecule-based magnetic materials. We have developed nano-porous magnetic materials, whose magnetic properties were changed by inclusion of small diamagnetic molecules. Switchable magnets by means of host-guest chemistry have been investigated.Host-guest complexes of tri- and tetra-radical-substituted azamacrocycles afforded the folded structures of the hosts where the radical oxygen atoms were coordinated to the guest metal ion, leading to enhanced antiferromagnetic couplings in the solid state and an ESR line broadening in the solution phase.We also prepared metal-radical hybrid magnets using bridging ligands as supramolecular synthons. Novel paramagnetic chelating ligands (pzNN, pzIN, pzbisNN, pzbislN, 6bpyNO, and 2pyNO) were developed and applied to the synthesis of mono-, di-, tri-, and polynuclear complexes (NN, IN, and NO stand for organic free radical groups). We have exploited potential utility of the bridging paramagnetic ligands (HIN, HNN, CnPNN). A strong character of a single-chain magnet (SCM) is operative in the magnetically ordered state in the one-dimensional Co-C4PNN complex, giving a largest class of the coercive field (52 kOe (4.1 MA m^-1) at 6 K).Several oligonuclear 3d-4f heterometallic complexes have been characterized as ground ferrimagnetic high-spin molecules. Lanthanide ions are supposed to be promising candidates for the elements of single-molecule magnets (SMMs) because of the large magnetic momentum and anisotropy.We have established the [Dy_2Cu], [Dy_4Cu], and [Dy_2,Cu_2] complexes as new SMMs and [Dy_2,Cu_2,]_n, as a SCM. A plausible mechanism for quantum tunneling of magnetization has been proposed for the first time among the 3d-4f heterometallic SMMs and SCMs.