New Electronic Structure of Quasi-One-Dimensional Halogen-Bridged Ni(III) Complexes with Strong Electron Correlations

准一维卤素桥接的混价金属化合物因其具有强烈的、具有大斯托克斯位移的价间电荷转移带发光、共振拉曼光谱的超频级数、大三阶非线性光学性质、孤子、极化子等非常有趣的物理性质而受到人们的关注。在这些化合物中，Pt和Pd化合物采用M (II)-M （IV）混合价态或CDW态，其中桥接卤素从相邻两个金属离子之间的中点扭曲。另一方面，Ni化合物呈Ni（III）态或SDW态，其中桥接卤素位于两个金属离子之间的中点。镍化合物与过氧化铜超导体的起始材料具有相似的电子结构。然后，掺杂到化合物中是非常有趣的。根据这一策略，我们采用电化学方法合成了镍钯混合金属配合物。为了研究它们的电子结构，我们测量了红外光谱、拉曼光谱、XPS光谱、俄歇光谱和ESR光谱。XPS和Auger谱显示，Ni离子的氧化态为+3态，但随着Ni组分的增加，Pd(II)-Pd（IV）混合价态逐渐接近Pd（III）态。在红外光谱中，Pd(II)-Pd（IV）中的双重态υ(N-H)逐渐转变为单重态，表明Pd(II)-Pd（IV）状态接近于Pd（III）状态。在拉曼光谱中，随着Ni组分的增加，IR光谱中υ(Pd(IV)-Br)的强度和泛音数减小。与纯混合Pd(II)-Pd（IV）和Ni（III）相比，室温下的积分自旋磁化率提高，表明Pd(II)-Pd（IV）态转变为Pd（III）态。如上所述，随着Ni（III）组分的增加，Pd(II)-Pd（IV）态受到影响，转变为Pd（III）态。这是由于Ni离子的电子相关性更强。少

Quasi-one-dimensional halogen-bridged mixed-valence metal compounds have attracted much attention because they show very interesting physical properties such as intense and diachronic intervalence charge transfer bandsm luminescence with large Stokes shifts, overton progression of resonance Raman spectra, large third order non-linear optical properties, solitons, polarons, etc. Among these compounds, the Pt and Pd compounds take the M (II)-M (IV) mixed valence states or CDW states, where the bridging halogens are distorted from the midpoints between neighboring two metal ions. On the other hand, the Ni compounds take the Ni(III) states or SDW states, where the bridging halogens are located at the midpoints between two metal ions. The Ni compounds have the similar electronic structures to those starting materials of copperoxide supercondutors. Then, the doping to the compounds are very interesting. According such strategy, we have synthesized Ni-Pd mixed-metal complexes by electrochemic … More al methods. In order to investigate their electronic structures, we have measured IR, Raman spectra, XPS, Auger spectra and ESR spectra.The XPS and Auger spectra revealed that the oxidation states of the Ni ions is +3, but the Pd(II)-Pd(IV) mixed-valence states approach the Pd(III) states with increase of Ni components. In the IR spectra, the doublet of υ(N-H) in Pd(II)-Pd(IV) is gradually changing to the singlet, indicating that the Pd(II)-Pd(IV) state approach the Pd(III) states. In the Raman spectra, the intensity and the number of overtone of υ(Pd(IV)-Br) decrease with increase of the Ni components as observed in IR spectra. The integrated spin susceptibilities at room temperature are enhanced compared with those pure mixture of Pd(II)-Pd(IV) and Ni(III), indicating that the Pd(II)-Pd(IV) states are changed to the Pd(III) sates.As mentioned above, the Pd(II)-Pd(IV) states are influenced and changed to the Pd(III) states with increase of the Ni(III) components. This is due to the stronger electron correlation of the Ni ions. Less