Micropores in crystalline dipeptides as seen from the crystal structure, He pycnometry, and 129Xe NMR spectroscopy.
Micropores in crystalline dipeptides as seen from the crystal structure, He pycnometry, and 129Xe NMR spectroscopy.
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DOI：
10.1021/ja060474j
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发表时间：
2006-04
影响因子：
15
通讯作者：
D. Soldatov;I. Moudrakovski;E. Grachev;J. Ripmeester
中科院分区：
文献类型：
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作者：
D. Soldatov;I. Moudrakovski;E. Grachev;J. Ripmeester
研究了八种结晶二肽：AV （Ala-Val）、VA （Val-Ala）、AI （Ala-Ile）、VV （Val-Val）、IA （Ile-Ala）、IV （Ile-Val）、VI （Val-Ile）和LS (Leu-Ser)（均为LL异构体）。前7个形成一个等构造系列（空间群P6(1)），而LS具有不同的结构（空间群P6(5)）。所有结构都显示了二肽分子的h键管状组装，从而形成了以孤立的一维通道形式开放的超微孔。材料的总孔隙率为4% ~ 12%（微孔体积为0.04 ~ 0.12 cm(3)/g）。基于晶体结构、He pypyometry和solid-state (129)Xe NMR方法的计算得到了微孔的几何形状和性质的全面描述。通道直径的顺序如下：AV > VA > AI > VV > IA > IV > VI, AV >5 A, IA > IV > AV约AI约VV > VI > LS， VA、IA和IV的螺旋直径约为2a，其余二肽的螺旋直径约为1a或更小。将所研究的二肽与其他超分子材料进行了比较，并讨论了其应用潜力。
Eight crystalline dipeptides were studied: AV (Ala-Val), VA (Val-Ala), AI (Ala-Ile), VV (Val-Val), IA (Ile-Ala), IV (Ile-Val), VI (Val-Ile), and LS (Leu-Ser) (all LL isomers). The first seven form an isostructural series (space group P6(1)), whereas LS has a different structure (P6(5)). All structures display H-bonded tubular assemblies of the dipeptide molecules resulting in open ultramicropores in the form of isolated one-dimensional (1D) channels. The total porosity of the materials ranges from 4 to 12% (micropore volume from 0.04 to 0.12 cm(3)/g). Calculations based on the crystal structures, He pycnometry, and solid-state (129)Xe NMR methods were used to obtain a comprehensive description of the geometry and properties of the micropores. The following order was established for the channel diameter: AV > VA > AI > VV > IA > IV > VI, with >5 A for AV and IA > IV > AV approximately AI approximately VV > VI > LS, with a helix diameter of approximately 2 A for VA, IA, and IV and approximately 1 A or less for the remaining dipeptides. A comparison of the dipeptides studied with other supramolecular materials is given and the potential for applications is discussed.