Heterogeneous asymmetric catalysis with homochiral metal-organic frameworks: network-structure-dependent catalytic activity.
Heterogeneous asymmetric catalysis with homochiral metal-organic frameworks: network-structure-dependent catalytic activity.
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DOI：
10.1002/anie.200602099
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发表时间：
2007-02
影响因子：
--
通讯作者：
Chuande Wu;Wenbin Lin
中科院分区：
文献类型：
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作者：
Chuande Wu;Wenbin Lin
通过合理的设计产生功能固体的前景刺激了最近对金属有机骨架(MOF)研究的爆炸性增长。[1，2]这一研究领域的特别关注集中在多孔MOF上，因为它们固有的分子筛、尺寸和形状选择特性使它们在许多应用中潜在地有用，例如催化、[3]气体存储、[4]分离、[5]和离子交换过程。[6]通过利用通常用于合成MOF的温和条件，我们和其他人通过引入包含正交功能的手性成分构建块成功地合成了具有催化活性的同手性多孔MOF。[7]MOF的单晶性质允许详细的结构询问，这使得有可能更详细地研究同手性多孔MOF的结构和催化活性之间的关系。对结构-活性关系的详细了解是通过合理选择构筑基团来进一步微调MOF催化性能的关键。在这里，我们报道了两个由相同的手性桥联配体和金属连接点构建的同手性多孔MOF。通过乙醚在Cd(NO3)2·4H2O和(R)-6，6‘-二氯-2，2’-二羟基-1，1‘-联萘-4，4’-联吡啶(L)[8]的混合溶剂中缓慢扩散合成了无色晶体[Cd(NO3)6]·7MeOH·5H2O(1)。化合物1属于四方P4122空间群，其不对称单元中有1.5cdII中心。[9]第一个(半占据)的cdII中心在赤道位置上与四个L配体(cd±N=2.310-2.317)和轴向位置上的两个硝酸氧原子(cd±N=2.356)八面体配位，而第二个cdII中心是七配位的两个双齿硝酸根(cd=2.317-2.552)，一个硝酸氧
The prospect of generating functional solids by rational design has spurred a recent explosive growth of interest in research into metal–organic frameworks (MOFs).[1, 2] A particular focus in this research area has been placed upon porous MOFs because of their intrinsic zeolitemimicking, size-and shape-selective properties which make them potentially useful in a number of applications such as catalysis,[3] gas storage,[4] separation,[5] and ion-exchange processes.[6] By taking advantage of the mild conditions that are typically used for the synthesis of MOFs, we and others have successfully synthesized catalytically active homochiral porous MOFs by incorporating chiral constituent building blocks that contained orthogonal functionalities.[7] The single-crystalline nature of MOFs allows detailed structural interrogation, which makes it possible to examine the relationship between the structure and the catalytic activity of homochiral porous MOFs in great detail. A detailed understanding of the structure–activity relationship is key to further fine-tuning the catalytic performance of MOFs by judicious choice of building blocks. Herein we report two homochiral porous MOFs built from the same chiral bridging ligand and metal connecting point. Their drastically different catalytic activities are readily rationalized on the basis of their different framework structures.Colorless crystals of [Cd3L4 (NO3) 6]· 7 MeOH· 5 H2O (1) were synthesized by slow diffusion of diethyl ether into a mixture of Cd (NO3) 2· 4 H2O and (R)-6, 6’-dichloro-2, 2’-dihydroxy-1, 1’-binaphthyl-4, 4’-bipyridine (L)[8] in DMF/CHCl3/MeOH at RT (Scheme 1). Compound 1 crystallizes in the tetragonal P4122 space group with 1.5 CdII centers in the asymmetric unit.[9] The first (half-occupied) CdII center is octahedrally coordinated to four L ligands (CdÀN= 2.310–2.317) in the equatorial positions and to two nitrate oxygen atoms (CdÀO= 2.356) in the axial positions, while the second CdII center is heptacoordinated to two bidentate nitrate groups (CdÀO= 2.317–2.552), one nitrate oxygen