Department of Chemical Engineering, East China University of Science and Technology, Shanghai, China.
Chirality. 2012 May;24(5):349-55. doi: 10.1002/chir.22013. Epub 2012 Apr 17.
During the resolution of 2-chloromandelic acid with (R)-(+)-N-benzyl-1-phenylethylamine, the crystals of the less soluble salt were grown, and their structure were determined and presented. The chiral discrimination mechanism was investigated by examining the weak intermolecular interactions (such as hydrogen bond, CH/π, and van der Waals interactions) and molecular packing mode in crystal structure of the less soluble diastereomeric salt. A one-dimensional double-chain hydrogen-bonding network and a "lock-and-key" supramolecular packing mode are disclosed. The investigation demonstrates that hydrophobic layers with corrugated surfaces can fit into the grooves of one another to realize a compact packing, when the molecular structure of resolving agent is much larger than that of the racemate. This "lock-and-key" assembly is recognized to be another characteristic of molecular packing contributing to the chiral discrimination, in addition to the well-known sandwich-like packing by hydrophobic layers with planar boundary surfaces.
在手性拆分 2-氯扁桃酸时，我们得到了其低溶解度盐的晶体，并对其结构进行了测定和阐述。通过考察弱分子间相互作用（如氢键、CH/π 和范德华相互作用）和晶体结构中低溶解度非对映异构体盐的分子堆积方式，我们研究了手性识别机制。揭示了一维双链氢键网络和“锁和钥匙”超分子堆积方式。研究表明，当拆分剂的分子结构远远大于外消旋体时，具有波纹表面的疏水性层可以相互契合，实现紧密堆积。这种“锁和钥匙”的组装方式被认为是除了具有平面边界表面的疏水性层的三明治状堆积之外，有助于手性识别的另一个分子堆积特征。
