A versatile family of interconvertible microporous chiral molecular frameworks: The first example of ligand control of network chirality
A versatile family of interconvertible microporous chiral molecular frameworks: The first example of ligand control of network chirality
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DOI：
10.1021/ja993814s
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发表时间：
2000-05-31
影响因子：
15
通讯作者：
Rosseinsky, MJ
中科院分区：
文献类型：
--
作者：
Kepert, CJ;Prior, TJ;Rosseinsky, MJ
描述了两类生长为同手性单晶的分子骨架。两者都是由三连接的手性(10,3)-a （Y*）网络的多次互渗透组成的，并且是1,3,5-苯三羧酸酯（btc）配体与八面体金属中心的三叉戟配位的结果，后者作为线性连接器。相互渗透的性质是由结合在金属中心赤道面上的辅助配体控制的。乙二醇（例如）以一种不相同的方式结合形成相a，该相具有28%的可溶溶剂体积，并包含四个互穿(10,3)-a网络。1,2-丙二醇（1,2-pd）作为双齿配体配位得到相B，其溶剂可达体积的比例大大提高了51%。因为只有两个（扭曲的）(10,3)-a'网络相互渗透。在空穴空间和与金属中心结合的配体都可以热释放：这一过程的动力学允许分离微孔脱溶晶体A和b。随着与赤道金属结合的配体进一步失去，多孔相会可逆地失去结晶度。暴露于简单醇的蒸气中，结晶度得以恢复，这也可以影响B向A的转化。两相呈现出化学中独特的互穿网络拓扑结构，并采用了分子固体中新的空间基团：A在P4(2)32中结晶，B在I4(1)32中结晶。B可以在对映体纯二醇模板上进行同手性生长。与金属结合的醇的立体化学反应控制了手性框架的螺旋度。1,2-丙二醇相的结构测定首次证明了手性分子可以在手性多孔框架固体中特异性地模板螺旋手性。
Two families of molecular frameworks which grow as homochiral single crystals are described. Both consist of multiple interpenetration of the three-connected chiral (10,3)-a (Y*) network and result from the tridentate coordination of the 1,3,5-benzenetricarboxylate (btc) Ligand to octahedral metal centers which act as Linear connectors. The nature of the interpenetration is controlled by the auxiliary ligands bound in the equatorial plane of the metal center. Ethylene glycol (eg) binds in a unidentate fashion to form phase A which has 28% accessible solvent volume and contains four interpenetrating (10,3)-a networks. 1,2-Propanediol (1,2-pd) coordinates as a bidentate ligand to yield a phase B with a greatly enhanced 51% of solvent accessible volume. because only two (distorted) (10,3)-a' networks interpenetrate. Ligands in the void space and bound to the metal center can both be liberated thermally: the kinetics of this process allow isolation of microporous desolvated crystalline A and B. The porous phases lose crystallinity reversibly upon further loss of ligands bound to the equatorial metal: crystallinity is restored upon exposure to the vapors of simple alcohols, which can also effect conversion of B to A. Both phases present interpenetrating network topologies that are unique to chemistry and adopt space groups that are new for molecular solids: A crystallizes in P4(2)32 and B adopts I4(1)32. B can be grown homochirally from enantiomerically pure diol template. The stereochemistry of the alcohol bound to the metal controls the helicity of the chiral framework. The structure determination of the 1,2-propanediol phase represents the first demonstration that chiral molecules can specifically template helix handedness in a chiral porous framework solid.