Hydrophilic-to-Hydrophobic Volume Ratios as Structural Determinant in Small-Length Scale Amphiphilic Crystalline Systems: Silver Salts of Phenylacetylene Nitriles with Pendant Oligo(ethylene Oxide) Ch

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• 作者：Zhengtao Xu ; Y.-H. Kiang ; Stephen Lee ; Emil B. Lobkovsky ; and Nathan Emmott
• 刊名：Journal of the American Chemical Society
• 出版年：2000
• 出版时间：September 6, 2000
• 年：2000
• 卷：122
• 期：35
• 页码：8376 - 8391
• 全文大小：1055K
• 年卷期：v.122,no.35(September 6, 2000)
• ISSN：1520-5126

文摘

A series of 13 silver salts of phenylacetylene nitriles with pendant oligo(ethylene oxide) side chainshave been crystallized, and their structures have been determined by single-crystal X-ray methods. All theorganic molecules are amphiphilic in that they contain either a hydrophobic rigid linear or 3-fold planarphenylacetylene backbone to which are attached four to six rather plastic hydrophilic oligo(ethylene oxide)side chains. Six of the crystal structures have one-dimensional coordination networks based on Ag-N andAg-O bonding, while the remainder are two-dimensional. Considering the hydrophilic and hydrophobic portionsof these crystals as separate components of the crystal structure, five of the crystal structures contain parallelcolumns of hydrophobic moieties within a matrix of hydrophilic groups, four contain layers of hydrophilicand hydrophobic portions stacked one on top of the other, two have perforated lamellar structures and two arebicontinuous. Volume ratios of hydrophilic to hydrophobic portions prove a strong determinant as to whichcrystal topology is adopted for a given crystal composition. Such volume ratios can be calculated from knowledgeof the molecular structure alone. A comparison is made to similar columnar and lamellar structures found inblock copolymers and liquid crystalline systems. Finally, a similar breakdown of crystal topology as a functionof volume ratios is found for aromatic-oligo(ethylene oxide) molecules in the Cambridge Structural Database.