Unconventional Heisenberg spin triangle in magnetic molecule {V15}: A proton nuclear magnetic resonance study
Unconventional Heisenberg spin triangle in magnetic molecule {V15}: A proton nuclear magnetic resonance study
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磁性分子{V15}中的非常规海森堡自旋三角形：质子核磁共振研究
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发表时间：
2003
期刊：
影响因子：
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通讯作者：
F. Borsa
中科院分区：
文献类型：
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作者：
D. Procissi;B. Suh;J. Jung;P. Kögerler;R. Vincent;F. Borsa
本文报道了分子式为K_6 [V_（15）As_6 O_（42）]~（19）（H_2O）的多钒酸盐簇合物{V_（15）}的~ 1H核磁共振（NMR）和弛豫的研究结果。将{V15}中的数据与{V6}中发表的数据进行比较，公式为[CN 3 H 6] 4 Na 2 [H4{V3 L} 2 P4 O 4]<$14 H2 O，其中包含两个独立的自旋三角形。温度T和磁场H的NMR线宽的依赖性很好地解释了质子核和钒离子自旋在两种化合物之间的磁偶极相互作用。质子弛豫速率T1−1的T和H依赖性在两种化合物中表现出很大的差异。这种差异表明两个海森堡自旋三角形系统的自旋动力学完全不同，其中在{V15}中，中心三角形中的VIV（s=1/2）的波动由与上下两个六边形中的VIV自旋的层间耦合主导。
We present results of 1H nuclear magnetic resonance (NMR) and relaxation in polyoxovanadate cluster {V15} with formula K6[V15As6O42]⋅9(H2O). The data in {V15} are compared with the published data in {V6} with the formula [CN3H6]4Na2[H4{V3L}2P4O4]⋅14H2O, which contains two independent spin triangles. Temperature T and field H dependence of the NMR linewidth are well explained by the magnetic dipolar interaction between the proton nuclei and vanadium ion spins in both compounds. T and H dependence of proton relaxation rate T1−1 show great differences in the two compounds. The difference indicates a completely different spin dynamics for the two Heisenberg spin-triangle systems whereby in {V15} the fluctuations of the VIV (s=1/2) in the central triangle are dominated by the interlayer coupling with the VIV spins in the two upper and lower hexagons.