Nomiya Kenji, Saku Yoshio, Yamada Shingo, Takahashi Wataru, Sekiya Hiromi, Shinohara Akira, Ishimaru Megumi, Sakai Yoshitaka
Department of Materials Science, Faculty of Science, Kanagawa University, Hiratsuka, Kanagawa 259-1293, Japan.
Dalton Trans. 2009 Jul 28(28):5504-11. doi: 10.1039/b902296a. Epub 2009 May 29.
The synthesis and characterization of two dinuclear HfIV and ZrIV complexes sandwiched between 2 mono-lacunary alpha-Keggin polyoxometalates (POMs), i.e., (Et2NH2)8[{alpha-PW11O39Hf(micro-OH)(H2O)}2].7H2O (Et2NH(2)-1) and (Et2NH2)8[{alpha-PW11O39Zr(micro-OH)(H2O)}2].7H2O (Et2NH(2)-2), are described. [Note: the moieties of their polyoxoanions are abbreviated simply as and , respectively.] A pair of HfIV- and ZrIV-containing POMs belonging to the same family were herein isolated as diethylammonium salts and were unambiguously characterized by complete elemental analysis, including sodium and oxygen analyses, TG/DTA, FT-IR, single-crystal X-ray structure analysis and solution (31P and 183W) NMR spectroscopy. Polyoxoanions 1 and 2 were isostructural with each other. The central [M2(micro-OH)2(H2O)2]6+ (M=Hf, Zr) cation unit was composed of 2 edge-sharing polyhedral M units, which were linked through 2 micro-OH groups and contained 1 water molecule coordinated to each metal center. Since the mono-lacunary Keggin POM acts as an oxygen-donor quadridentate ligand, the Hf and Zr centers are 7-coordinate. It should be noted that the present 2 Keggin 2:2-type compounds, Et2NH(2)-1 and Et2NH(2)-2, undergo a reversible conversion to Keggin 1:2-type complexes [M(alpha-PW11O39)2]10-, respectively, in solution under appropriate conditions. The synthesis of Et2NH(2)-1 and Et2NH(2)-2 is based on such an interconversion. The Zr compound Et2NH(2)-2 was rigorously compared with the 3 Zr POMs (OK-1-OK-3), recently reported by Kholdeeva's group: their POMs in a different protonation-state did not contain any coordinating water molecules.
本文描述了夹在两个单缺位α-凯吉型多金属氧酸盐（POMs）之间的两种双核HfIV和ZrIV配合物的合成与表征，即(Et2NH2)8[{α-PW11O39Hf(μ-OH)(H2O)}2]·7H2O（Et2NH(2)-1）和(Et2NH2)8[{α-PW11O39Zr(μ-OH)(H2O)}2]·7H2O（Et2NH(2)-2）。[注：它们的多氧阴离子部分分别简称为 和 。]本文分离得到了一对属于同一家族的含HfIV和ZrIV的POMs，并以二乙铵盐的形式存在，通过完整的元素分析（包括钠和氧分析）、TG/DTA、FT-IR、单晶X射线结构分析以及溶液（31P和183W）NMR光谱对其进行了明确的表征。多氧阴离子1和2彼此同构。中心[M2(μ-OH)2(H2O)2]6+（M = Hf、Zr）阳离子单元由2个通过边共享的多面体M单元组成，它们通过2个μ-OH基团相连，且每个金属中心含有1个配位水分子。由于单缺位凯吉型POM作为氧供体四齿配体，Hf和Zr中心为七配位。应当指出的是，目前的两种凯吉型2:2型化合物Et2NH(2)-1和Et2NH(2)-2在适当条件下在溶液中分别可逆地转化为凯吉型1:2型配合物[M(α-PW11O39)2]10-。Et2NH(2)-1和Et2NH(2)-2的合成基于这种相互转化。将Zr化合物Et2NH(2)-2与Kholdeeva小组最近报道的3种Zr POMs（OK-1 - OK-3）进行了严格比较：它们处于不同质子化状态的POMs不含任何配位水分子。
