Condensation of Keggin Anions Containing Chromium(III) and Aluminum(III), Respectively. 1. Synthesis and X-ray Structural Determination of [{A-.alpha.-SiO4W9O30(OH)3Cr3}2(OH)3]11-
Condensation of Keggin Anions Containing Chromium(III) and Aluminum(III), Respectively. 1. Synthesis and X-ray Structural Determination of [{A-.alpha.-SiO4W9O30(OH)3Cr3}2(OH)3]11-
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分别含有铬 (III) 和铝 (III) 的 Keggin 阴离子的缩合。
DOI：
10.1021/ic00124a018
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发表时间：
1995
影响因子：
4.6
通讯作者：
R. Stoesser
中科院分区：
文献类型：
--
作者：
K. Wassermann;R. Palm;H. Lunk;J. Fuchs;N. Steinfeldt;R. Stoesser
通过[Aa-Si_（04）W_（903）O（OH）_3Cr_3（OH_2）_3]~（4-）在水溶液中的缩合反应，得到了第一个含低价杂元素的“二聚”Keggin阴离子[{Aa-Si_（04）W_（903）O（OH）_3Cr_3}_2（OH）_3]~（11-）。通过UV/维斯光谱法跟踪单体单元之间的反应。（NH_4）_2 [{Aa-Si_（04）W_（90）_3（OH）_3Cr_（3）}_2（OH）_3）_6H_（20）_2的单晶X射线结构分析。5NH_4Cl（P42/nmc; a，B= 21.778（2）A，c= 21.300（2）A; Z= 4; R= 0.062（对2961个观察到的独立反射）表明两个Keggin阴离子通过三个Cr-OH-Cr桥连接。通过元素分析、红外光谱和电子顺磁共振谱对产物进行了表征。在比较研究中讨论了单体和二聚体物种的键距和键角。单，二，和三重铬（III）取代Keggin阴离子的游离酸的滴定实验的结果已被用于描述的“二聚体形成”。
The first example of a “dimerized” Keggin anion,[{Aa-Si04W903o (OH) 3Cr3} 2 (OH) 3] ll_, containinglow-valent heteroelements has been obtained by the condensation of [Aa-Si04W903o (OH) 3Cr3 (OH2) 3] 4~ in aqueous solution. The reaction between the monomeric units was followed by UV/vis spectroscopy. The single-crystalX-ray structural analysis of (NH4) ii [{Aa-Si04W903o (OH) 3Cr3} 2 (OH) 3]'6H202. 5NH4Cl (P42/nmc; a, b= 21.778 (2) A, c= 21.300 (2) A; Z= 4; R= 0.062 for 2961 observed independent reflections) reveals thatthe two Keggin anions are linked via three Cr—OH—Cr bridges. Isolation of the new polyxometalate was accomplished as NH4+ and K+ salts, respectively, which were characterized by elemental analysis, IR and ESR spectroscopy. The bond distances and bond angles for the monomeric and dimeric species are discussed in a comparative study. The results from titration experiments of the free acids for mono-, di-, and triple chromium (III) substituted Keggin anions have been used for the description of the “dimer formation”.