Symmetry breaking of α-[H2W12O40](6-) depends on the transformation of isopolyoxotungstates.
Symmetry breaking of α-[H2W12O40](6-) depends on the transformation of isopolyoxotungstates.
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DOI：
10.1021/ic500062j
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发表时间：
2014-05
影响因子：
4.6
通讯作者：
Yingnan Chi;P. Shen;Feng-Yun Cui;Zhengguo Lin;Shi‐Lu Chen;Chang-Wen Hu
中科院分区：
文献类型：
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作者：
Yingnan Chi;P. Shen;Feng-Yun Cui;Zhengguo Lin;Shi‐Lu Chen;Chang-Wen Hu
合成了两个手性空间群为P212121的手性一维链状化合物[Cu3(L1)3(H2O)2(HW12O40)]·4H2O(1a，b；L1=2-(4，6-bis(pyridin-2-yl)pyridin-2-yl)pyridine)，)，并在没有任何手性源的情况下自发拆分。有趣的是，化合物1a，b可以从[W7O24](6-)水溶液、[(n-C4H9)4N]4[W10O32]或Na10[H2W12O42]中得到，但当[H2W12O40](6-)水溶液为起始原料时，得到无手性化合物[CuL1]2[H4W12O40]·5H2O(2)。当使用与L1配位方式相似的联吡啶配体(L2)时，从[W7O24](6-)水溶液或Na10[H2W12O42]水溶液中得到了介晶二聚体[Cu3(L2)3(H2O)(H2W12O40)]2·4H2O(3)，但从[H2W12O40](6-)水溶液中只分离到了化合物[Cu2(L2)2Cl2]2[W10O32](4)。值得注意的是，在化合物1a、b和3中，α-[H_2W_(12)O_(40)](6-)原子簇的对称性被以类似方式与金属-有机单元的不对称配位破坏。除了[H_2W_(12)O_(40)](6-)外，基于三配位的[H_2W_(12)O_(40)](6-)簇合物的不对称亚基可以从几种异多氧钨酸盐来源获得，因此我们推测α-[H_2W_(12)O_(40)](6-)的对称性破缺依赖于异多氧钨酸盐的转变。此外，在转变过程中，提出了一个可能的反应中间体作为1a，b化合物[Cu3(L1)3(H2O)3(H4W11O38)](5)的前体，并用密度泛函理论(DFT)计算对其进行了表征。
Two enantiotopic 1D chain compounds, [Cu3(L1)3(H2O)2(H2W12O40)]·4H2O (1a,b; L1 = 2-(4,6-bis(pyridin-2-yl)pyridin-2-yl)pyridine), crystallizing in the chiral space group P212121 were prepared and spontaneously resolved in the absence of any chiral source. Interestingly, compounds 1a,b can be prepared from a [W7O24](6-) aqueous solution, [(n-C4H9)4N]4[W10O32], or Na10[H2W12O42], but when [H2W12O40](6-) aqueous solution was the starting material, the achiral compound [CuL1]2[H4W12O40]·5H2O (2) was obtained. When a terpyridine ligand (L2) having a coordination mode similar to that of L1 was used, the mesomeric dimer [Cu3(L2)3(H2O)(H2W12O40)]2·4H2O (3) was obtained from [W7O24](6-) aqueous solution or Na10[H2W12O42], but from [H2W12O40](6-) aqueous solution only compound [Cu2(L2)2Cl2]2[W10O32] (4) was isolated. It is notable that in compounds 1a,b and 3 the symmetry of the α-[H2W12O40](6-) cluster is broken by asymmetric coordination with metal-organic units in a similar mode. As the asymmetric subunit based on a tridecorated [H2W12O40](6-) cluster can be obtained from several isopolyoxotungstate sources except for [H2W12O40](6-), we speculate that the symmetry breaking of α-[H2W12O40](6-) depends on the transformation of isopolyoxotungstates. Furthermore, during the transformation a possible reaction intermediate as the precursor for 1a,b, compound [Cu3(L1)3(H2O)3(H4W11O38)] (5), has been presented and characterized by density functional theory (DFT) calculations.