Armstrong Robert S, Atkinson Ian M, Carter Elizabeth, Mahinay Myrna S, Skelton Brian W, Turner Peter, Wei Gang, White Allan H, Lindoy Leonard F
School of Chemistry, University of Sydney, New South Wales 2006, Australia.
Proc Natl Acad Sci U S A. 2002 Apr 16;99(8):4987-92. doi: 10.1073/pnas.062640099. Epub 2002 Apr 2.
(1H) and (13)C NMR titrations in both CDCl(3) and CD(3)OD demonstrate that 4-tert-butylbenzoic acid interacts with both propane-1,2-diamine and propane-1,3-diamine to yield 1:2 host-guest complexes in these solvents. Based on this observation, the isolation of new three-dimensional molecular arrays through cocrystallization of the above diamines and 4-tert-butylbenzoic acid (in a 1:2 molar ratio) has been achieved. X-ray studies of these self-assembled structures show that they incorporate [propane-1,2-diamine x (4-tert-butylbenzoic acid)(2)] or [propane-1,3-diamine x (4-tert-butylbenzoic acid)(2)] hydrogen-bonded motifs. Three structural derivatives of the latter type (two monohydrate forms and one anhydrous form) have been characterized. The structures are compared with a previously described three-dimensional array based on the "parent" [ethane-1,2-diamine x (benzoic acid)(2)] motif. Similarities occur between each of the structures. In each, a two-dimensional "ionic" layer consisting of an extensive network of hydrogen bonds is sandwiched between two "less polar" aromatic ring-containing layers. In the respective ionic layers, the carboxylic acid protons have been transferred onto the amines to yield diammonium cations, with all ammonium protons being involved in hydrogen bonding. In part, the adoption of these unusual layered structures seems to reflect a tendency toward maximization of both the number and strengths of the hydrogen bond interactions in the respective ionic layers.
在CDCl₃和CD₃OD中进行的¹H和¹³C NMR滴定表明，4-叔丁基苯甲酸与1,2-丙二胺和1,3-丙二胺相互作用，在这些溶剂中形成1:2的主客体配合物。基于这一观察结果，通过上述二胺与4-叔丁基苯甲酸（摩尔比为1:2）的共结晶实现了新型三维分子阵列的分离。对这些自组装结构的X射线研究表明，它们包含[1,2-丙二胺·(4-叔丁基苯甲酸)₂]或[1,3-丙二胺·(4-叔丁基苯甲酸)₂]氢键基序。已对后一种类型的三种结构衍生物（两种一水合物形式和一种无水形式）进行了表征。将这些结构与先前描述的基于“母体”[1,2-乙二胺·(苯甲酸)₂]基序的三维阵列进行了比较。各结构之间存在相似之处。在每种结构中，由广泛的氢键网络组成的二维“离子”层夹在两个“极性较小”的含芳环层之间。在各自的离子层中，羧酸质子已转移到胺上，生成二铵阳离子，所有铵质子都参与氢键形成。在某种程度上，这些不寻常的层状结构的形成似乎反映了在各自离子层中使氢键相互作用的数量和强度最大化的趋势。
