Study on the construction of photoresponsive single-molecule magnets in frozen solutions

冷冻溶液中光响应单分子磁体的构建研究

• 批准号: 14204071
• 负责人: KOGA Noboru
• 金额: $ 33.78万
• 依托单位: KYUSHU UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (A)
• 财政年份: 2002
• 资助国家: 日本
• 起止时间: 2002 至 2004
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-14204071/
• 关键词: Single-molecule Magnet; Hysteresis; Carbene; Quantum Tunneling Effect; Cobalt Complexes; Ac Magnetic susceptibility; 磁化のヒステリシス; 1:4コバルト錯体; ニトロキシドラジカル; ヘテロスピン; 分子磁性; 光応答; 機能性ナノマテリアル; 磁気異方性; ポリカルベン; ジアゾーピリジル誘導体; SQUID; ヘテロスピン系; 剛体溶媒; 光照射

For the construction of monometallic single-molecule magnets (SMMs), We proposed to use the heterospin systems consisting of the 2p organic spins and the 3d metal ions. In our heterospin systems, pyridine ligands carrying mono-, di-, and tricarbene (S=2/2,4/2, and 6/2, respectively) and high-spin Co(II) ions, CoCl_2 and Co(p-tolsal)_2, were employed as the 2p organic spins and the 3d metal ions, respectively. Various combinations of two components, diazo-pyridine ligands and Co(II) ions, in solutions were mixed in appropriate ratios. To avoid the intermolecular magnetic interaction, the frozen solution conditions were used as the samples for SQUID measurements. The ac and dc magnetic susceptibility measurements for six samples of the complexes were carried out before and after irradiation. In ac magnetic susceptibility measurements after irradiation of six samples, the in-phase and out-of phase components (χ' and χ", respectively) with the applying frequency dependence were observed, indicating that the cobalt complexes have slow magnetic relaxations. The values of the activation barriers, U_<eff>, for flipping the spin were estimated to be 40- 93 K for the six complexes. In the dc field dependence of magnetization at 1.9 K, relatively large hysteresis loops with coercive force, H_c=7-10 kOe for the six complexes were observed. Obtained values of U_<eff>, τ_0, and H_c, for all six complexes were summarized together with those for the related complexes. In this work, we successfully prepared the monometallic single-molecule magnets in frozen solution. Furthermore, by changing the S values of the complexes systematically, it was concluded that the activation barrier, U_<eff>, for flipping the spin and the relaxation time due to the resonant quantum tunneling effect increased and decreased, respectively, with increasing S value of the complex.

对于单金属单分子磁体（SMM）金属离子的重量高旋转CO（II）离子，COCL_2和CO_2在溶液中将两种成分的各种组合和CO在溶液中混合在一起在辐照六个样品后测量之前和之后进行的AC和DC磁敏感性测量值钴络合物具有缓慢的磁性弛豫，据估计自旋为40-93 k，在1.9 K的DC场依赖性中。 -10对于六个组合的KOE是U_ <eff>，τ_0和H_C，对于所有六个复合物，与您相关的复合物一起汇总了。总结了激活屏障U_ <fef>，用于翻转自旋和由于谐振量子隧道效应而引起的松弛时间增加并减少，尊重，并增加了coptrecec的S值。

项目成果

From High-spin Polycarbenes to Carbene-based Magnets in Carbene Chemistry : from Fleeting Intermediates to Powerful Reagents

卡宾化学中从高自旋聚卡宾到卡宾基磁体：从短暂的中间体到强大的试剂

• 发表时间: 2002
• 作者: N.Koga;H.Iwamura
• 通讯作者: H.Iwamura

From High-spin Polycarbenes to Carbene-based Magnets, Carbene Chemistry: from Fleeting Intermediates to Powerful Reagents, Chapter 9

从高自旋聚卡宾到卡宾磁体，卡宾化学：从短暂的中间体到强大的试剂，第 9 章

• 发表时间: 2002
• 作者: N.Koga;H.Iwamura
• 通讯作者: H.Iwamura

N.Koga, H.Iwamura: "Carbene Chemistry : from Fleeting Intermediates to Powerful Reagents, From High-spin Polycarbenes to Carbene-based Magnets"G. Bertrand(Ed.), FontisMedia S. A.. 22 (2002)

N.Koga、H.Iwamura：“卡宾化学：从短暂的中间体到强大的试剂，从高自旋聚卡宾到卡宾基磁体”G。

Magnetic properties of dendritic polycarbenes substituted by bulky peripheral groups

大体积外围基团取代的树枝状聚卡宾的磁性

• 发表时间: 2005
• 期刊: Polyhedron
• 影响因子: 2.6
• 作者: Takeyuki Akita;Noboru Koga
• 通讯作者: Noboru Koga

J.-P.Zhang, M.Suehiro, A.Sakane, S.Karasawa, T.Akita, N.Koga: "Theoretical Study on the Exchange Interaction between Metal Ion and Organic Radical through Pyridine, Bipyridine, and Terpyridine Ligands"Mol. Cryst. Liq. Cryst.. 376. 431-436 (2002)

J.-P.Zhang、M.Suehiro、A.Sakane、S.Karasawa、T.Akita、N.Koga：“金属离子与有机自由基通过吡啶、联吡啶和三联吡啶配体的交换相互作用的理论研究”Mol