Structural isomerism of an anionic nanoporous In-MOF with interpenetrated diamond-like topology
Structural isomerism of an anionic nanoporous In-MOF with interpenetrated diamond-like topology
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DOI：
10.1039/c2ce06538j
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发表时间：
2012-01-01
期刊：
影响因子：
3.1
通讯作者：
Huh, Seong
中科院分区：
文献类型：
--
作者：
Gu, Ja-Min;Kim, Sung-Jin;Huh, Seong
以4，4 '-联苯二甲酸为桥连配体，In（NO3）（3）为中心点，通过引入xH（2）O，制备了具有拓扑结构的新型In-MOFs。两种异构形式的In-MOFs的独立制备和其特征在于通过X射线晶体学，粉末X射线衍射（PXRD），热重分析（TGA），元素分析，和气体吸附分析。通过简单地使用不同的溶剂，N，N-二甲基甲酰胺或N，N-二乙基甲酰胺，我们获得了两种新的In-MOFs。尽管In-III节点的配位模式相同，但这两种阴离子MOFs采用了不同的晶体结构。一种异构体（1）显示出整体4重互穿的单节4连接金刚石网络，Z（t）= 1，Z（n）= 2（IIa类）。另一个（2）为4重互穿的单节点4-连通菱形网络，Z（t）= 2，Z（n）= 2（Ⅲ a类）。因此，尽管相同的金属-配体连接性，1和2是基于链化方式的不寻常的异构体MOFs。这可能是由于在不同尺寸的抗衡阳离子的存在下，以In为中心的假四面体基序的柔性键合性质。In-MOF 1和2表现出不同的反离子分布和孔隙率特性。有趣的是，In-MOF 1显示出从结晶形式->非晶化形式（活化后）->结晶状态（溶解后）的可逆骨架转变。这种可逆转化也可以通过In-III离子与四个η（2）-配位的4，4 '-BPDC配体的柔性键合性质来解释。
Topologically interesting new In-MOFs were prepared by using a 4,4'-biphenyldicarboxylate bridging ligand and In(NO3)(3)center dot xH(2)O. Two isomeric forms of In-MOFs were independently prepared and characterized by X-ray crystallography, powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA), elemental analysis, and gas sorption analysis. By simply using different solvents, N,N-dimethylformamide or N,N-diethylformamide, we obtained two new In-MOFs. Despite the same coordination mode of an In-III node, these two anionic MOFs adopted distinct crystal structures. One isomer (1) showed an overall 4-fold interpenetrated uninodal 4-connected diamond network with Z(t) = 1 and Z(n) = 2 (class IIa). The other (2) showed a 4-fold interpenetrated uninodal 4-connected diamond network with Z(t) = 2 and Z(n) = 2 (class IIIa). Thus, despite the same metal-ligand connectivity, 1 and 2 are unusual isomeric MOFs based on the ways of catenation. This may be accounted for by the flexible bonding nature of the In-centered pseudotetrahedral motif in the presence of counter-cations with different dimensions. The In-MOFs 1 and 2 exhibited different counter ion distributions and porosity properties. Interestingly, the In-MOF 1 showed a reversible framework transformation from crystalline form -> amorphized form (after activation) -> crystalline state (after resolvation). This reversible transformation can also be explained by the flexible bonding nature of the In-III ion with four eta(2)-coordinated 4,4'-BPDC ligands.