Lan Ya-Qian, Li Shun-Li, Wang Xin-Long, Shao Kui-Zhan, Du Dong-Ying, Zang Hong-Ying, Su Zhong-Min
Institute of Functional Material Chemistry; Key Laboratory of Polyoxometalate Science of Ministry of Education, Faculty of Chemistry, Northeast Normal University, Changchun 130024, China.
Inorg Chem. 2008 Sep 15;47(18):8179-87. doi: 10.1021/ic800702d. Epub 2008 Aug 13.
Six polyoxometalate (POM)-based hybrid materials have been designed and synthesized based on octamolybdate building blocks and copper-organic units at different pH values under hydrothermal conditions, namely, [H2bbi][Cu(II)(bbi)2(beta-Mo8O26)] (1), [Cu(II)(bbi)2(H2O)(beta-Mo8O26)0.5] (2), [Cu(II)(bbi)2(alpha-Mo8O26)][Cu(I)(bbi)]2 (3), [Cu(II)Cu(I)(bbi)3(alpha-Mo8O26)][Cu(I)(bbi)] (4), [Cu(I)(bbi)]2[Cu(I)2(bbi)2(delta-Mo8O26)0.5][alpha-Mo8O26]0.5 (5), and [Cu(I)(bbi)][Cu(I)(bbi)(theta-Mo8O26)0.5] (6), where bbi is 1,1'-(1,4-butanediyl)bis(imidazole). Their crystal structures have been determined by X-ray diffraction. In compound 1, the bbi ligands with bis-monodentate coordination modes link Cu(II) cations to generate a 2D copper-organic unit with (4, 4) net, which is pillared by the (beta-Mo8O26)(4-) anions to form a 3D framework with alpha-Po topology. The similar copper-organic units are connected alternately by (beta-Mo8O26)(4-) anions to generate a 3D 2-fold interpenetrating (4,6)-connected framework with (4(4) x 6(2))(4(4) x 6(10) x 8) topology in compound 2. Compounds 3 and 4 are supramolecular isomers with polythreaded topology. If Cu (I)...O interactions are considered, the structure of 3 is a novel self-penetrating (3,4,6)-connected framework with (5(2) x 8)2(5(4) x 6 x 8)(4(4) x 6(10) x 10) topology, and the structure of 4 is a (4,6)-connected framework with (4(2) x 6(3) x 7)(5.6(4) x 8)(4(2) x 5(6) x 6(6) x 8)(4(2) x 5(6) x 6(4) x 7 x 8(2)) topology. Different from compounds 3 and 4, compounds 5 and 6 are supramolecular isomers with polythreaded topology based on different octamolybdate isomers. By careful inspection of the structures of 1-6, it is believed that various copper-organic units, which are formed by bbi ligands combined with Cu(II)/Cu(I) cations, octamolybdates with different types and coordination modes, and the nonbonding interactions between polyanions and copper-organic units are important for the formation of the different structures. In addition, with step by step increasing of the amount of organic amine, we have achieved the transformation of Cu(II) ions into Cu(I) ones in different degrees in POMs-based metal-organic frameworks (MOFs) for the first time. The infrared spectra, X-ray powder diffraction, and thermogravimetric analyses have been investigated in detail for all compounds, and the luminescent properties have been also been investigated for compounds 3 and 4.
基于八钼酸盐结构单元和铜有机单元，在水热条件下于不同pH值设计合成了六种基于多金属氧酸盐（POM）的杂化材料，即[H2bbi][Cu(II)(bbi)2(beta-Mo8O26)]（1）、[Cu(II)(bbi)2(H2O)(beta-Mo8O26)0.5]（2）、[Cu(II)(bbi)2(alpha-Mo8O26)][Cu(I)(bbi)]2（3）、[Cu(II)Cu(I)(bbi)3(alpha-Mo8O26)][Cu(I)(bbi)]（4）、[Cu(I)(bbi)]2[Cu(I)2(bbi)2(delta-Mo8O26)0.5][alpha-Mo8O26]0.5（5）和[Cu(I)(bbi)][Cu(I)(bbi)(theta-Mo8O26)0.5]（6），其中bbi为1,1'-(1,4-丁二基)双(咪唑)。通过X射线衍射测定了它们的晶体结构。在化合物1中，具有双单齿配位模式的bbi配体连接Cu(II)阳离子生成具有(4,4)网的二维铜有机单元，该单元由(beta-Mo8O26)(4-)阴离子支撑形成具有alpha-Po拓扑结构的三维框架。在化合物2中，类似的铜有机单元通过(beta-Mo8O26)(4-)阴离子交替连接生成具有(4(4) x 6(2))(4(4) x 6(10) x 8)拓扑结构的三维2重互穿(4,6)-连接框架。化合物3和4是具有多线程拓扑结构的超分子异构体。如果考虑Cu(I)...O相互作用，3的结构是具有(5(2) x 8)2(5(4) x 6 x 8)(4(4) x 6(10) x 10)拓扑结构的新型自穿入(3,4,6)-连接框架，4的结构是具有(4(2) x 6(3) x 7)(5.6(4) x 8)(4(2) x 5(6) x 6(6) x 8)(4(2) x 5(6) x 6(4) x 7 x 8(2))拓扑结构的(4,6)-连接框架。与化合物3和4不同，化合物5和6是基于不同八钼酸盐异构体的具有多线程拓扑结构的超分子异构体。通过仔细研究1 - 6的结构，认为由bbi配体与Cu(II)/Cu(I)阳离子结合形成的各种铜有机单元、不同类型和配位模式的八钼酸盐以及多阴离子与铜有机单元之间的非键相互作用对不同结构的形成很重要。此外，随着有机胺用量的逐步增加，我们首次在基于POM的金属有机框架（MOF）中实现了Cu(II)离子不同程度地转化为Cu(I)离子。对所有化合物详细研究了红外光谱、X射线粉末衍射和热重分析，还研究了化合物3和4的发光性质。
