Predominance of Covalency in Water-Vapor-Responsive MMX-Type Chain Complexes revealed by (129)I Moesbauer Spectroscopy
Predominance of Covalency in Water-Vapor-Responsive MMX-Type Chain Complexes revealed by (129)I Moesbauer Spectroscopy
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(129)I Moesbauer 光谱揭示水蒸气响应 MMX 型链配合物中共价的优势
DOI：
10.1039/c4dt00627e
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
and M. Yamashita
中科院分区：
文献类型：
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作者：
H. Iguchi;S. Kitao;M. Seto;S. Takaishi;and M. Yamashita
利用~（129）I穆斯堡尔谱学对水蒸气响应的MMX型准一维碘桥铂配合物（MMX链）进行了定量研究。在K2中观察到两组八胞胎（H3 NC 3 H6 NH3）[Pt 2（pop）4 I]·4 H2O（2·4 H2O）和一个八重态（cis-H_3 NCH_2CHCHCH_2NH_3）[Pt_2（pop）_4I]·4H_2O（1·4H_2O）和脱水配合物（1和2）显示出独特的交替电荷极化+电荷密度波（ACP + CDW）电子态和电荷密度波（CDW）电子态。这些光谱对应于它们的晶体结构和脱水时电子状态的变化。由于这些配合物由带正电荷和带负电荷的层交替排列组成，因此根据异构体位移（IS）讨论了碘离子上的电荷（ρIS）。水蒸气响应性MMX链的ρIS主要为-0.13至-0.21，这是迄今为止报道的所有MMX链中最小的。因此，这表明碘离子上的负电荷强烈地贡献给这些配合物中的Pt离子。这种共价相互作用在ACP + CDW状态以及CDW状态中占主导地位。因此，ACP + CDW态实际上是具有ACP型晶格畸变的CDW态。由于ρIS随Pt-I-Pt距离的减小而变小，因此可以推断共价相互作用在决定含pop（= P2 H2O 52-）配体的MMX链的电子状态中起重要作用。
129I Mössbauer spectroscopy was applied to water-vapor-responsive MMX-type quasi-one-dimensional iodide-bridged Pt complexes (MMX chains) in order to investigate their electronic state quantitatively. Two sets of octuplets observed in K2(H3NC3H6NH3)[Pt2(pop)4I]·4H2O (2·4H2O) and one octuplet observed in K2(cis-H3NCH2CHCHCH2NH3)[Pt2(pop)4I]·4H2O (1·4H2O) and dehydrated complexes (1 and 2) indicate a unique alternating charge-polarization + charge-density-wave (ACP + CDW) electronic state and a charge-density-wave (CDW) electronic state, respectively. These spectra correspond to their crystal structure and the change of electronic states upon dehydration. Since these complexes consist of an alternating array of positively charged and negatively charged layers, the charge on the iodide ion (ρIS) was discussed on the basis of the isomer shift (IS). The ρIS of the water-vapor-responsive MMX chains was mainly −0.13 to −0.21, which are the smallest of all MMX chains reported so far. Hence, it indicates that the negative charge on the iodide ion is strongly donated to the Pt ion in these complexes. This covalent interaction predominates in the ACP + CDW state as well as in the CDW state. Therefore, the ACP + CDW state is in fact the CDW state with the ACP-type lattice distortion. Because the ρIS became smaller with the decreasing Pt–I–Pt distance, it can be concluded that the covalent interaction plays an important role in determining the electronic states of the MMX chains with pop (= P2H2O52–) ligands.