Electron-Spin Dynamics and Structures in Halogen-Bridged 1-D Metal Complexes Studied by Solid NMR
Electron-Spin Dynamics and Structures in Halogen-Bridged 1-D Metal Complexes Studied by Solid NMR
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通过固体核磁共振研究卤素桥一维金属配合物中的电子自旋动力学和结构
DOI：
10.1246/bcsj.77.1075
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发表时间：
2004
期刊：
影响因子：
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通讯作者：
R. Ikeda
中科院分区：
文献类型：
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作者：
R. Ikeda
应用磁共振技术研究了卤素桥联的混价和平均价金属络合物的一维体系的磁特性。用核磁共振弛豫方法灵敏地探测到了一维链上大量顺磁性Pt3+和Pd3+位杂质形成的中性孤子和极化子。它们在[MI I(En)2]-[M V I Br2(En)2](ClO4)4(M：PT，Pd)中的一维扩散速度与在反式聚乙炔中相当。~1H核磁共振谱和~1C核磁共振谱表明，[Ni I X(Chxn)2]X2(X：CL，Br)处于平均价态，形成了S=1/2维海森堡反铁磁链。[NiBr(Chxn)2]Br2是迄今报道的交换作用最强的化合物，有望在低于100K的低温下转变为一种新的状态。通过对与一维链状结构相关的热运动和相变的研究，用核磁共振弛豫测量发现，在X射线衍射没有检测到的高度不对称的双势垒中，[NiBr(Chxn)2](ClO4)4(X：CL，Br)中存在着铂(En)2的动态无序构象。
Magnetic properties characteristic in 1-D systems were investigated in halogen-bridged mixed-valence and averaged-valence metal complexes by applying magnetic resonance techniques. Neutral-solitons and polarons formed from impurity amounts of paramagnetic Pt 3 + and Pd 3 + sites in 1-D chains were sensitively detected by the NMR relaxation measurement. Their rapid 1-D diffusion comparable to that in trans-polyacetylene was revealed in [M I I (en) 2 ]-[M V I Br 2 (en) 2 ](ClO 4 ) 4 (M: Pt, Pd). From 1 3 C NMR spectra and 1 H NMR relaxation studies, [Ni I I I X(chxn) 2 ]X 2 (X: Cl, Br) was shown to be in an averaged-valence state forming S = ½ 1-D Heisenberg antiferromagnetic chains. [NiBr(chxn) 2 ]Br 2 revealed to have the largest exchange interaction so far reported, was expected to transform into a new state at low-temperatures below 100 K. From studies on thermal motions and phase transitions associated with the 1-D chain-structure in [Pt(en) 2 ][PtX 2 (en) 2 ](ClO 4 ) 4 (X: Cl, Br), the presence of the dynamic disorder of the Pt(en) 2 chelate-ring conformation in a highly asymmetric double-well potential undetected by the X-ray diffraction was detected by the NMR relaxation measurement.
鸟海幸四郎：固态通信。
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