Crystallographic Study of Macrocyclic Cyclophane Inclusion Compounds

对大环杂环烷（N,N^1,N^<11>,N^<111> -四甲基-2,11,20,29-四氮杂-[3.3.3.3]副环烷[1]）与苯、吡啶、CHCl_3、CH_3CN、CO_2、CH_2Cl_2和CH_2BrCl包合物进行了x射线晶体分析。这些包合物的晶体表现出客体依赖多态性，分为：1：苯（P2_l，Z=4）， 1：吡啶（Pl，Z= 1）， 1:CHCl_3 (C2， Z=2)， 1:CH_3CN和1:CO_2 (C2/c， Z=4)， 1:CH_2Cl_2和1:CH_2BrCl （C2/c， Z=8）。在这些结晶包合物中，l作为S构象的R构象存在，因为l的大环构象在固态中被冻结。L沿b轴排列，形成容纳客分子L: L比例的分子柱。一个分子柱是手性的，因为它由l的所有R或S构象组成。手性晶体由所有R或S构象组成，而外消旋晶体由R和S构象组成。这五种不同的晶体结构可以从柱的填充方式来解释。柱的排列与l中苯环的倾斜角有很大关系，倾斜角取决于客体分子的大小和形状。未络合l的大环构象（C_<2v>）与络合l的大环构象（C_<2v>）不同。通过分子力学计算对l的构象分析表明，l具有包括对映体在内的6种稳定构象（最大和最小立体能之差为2.3 kcal/mol），表明l在溶液中这6种构象之间可以自由相互转化。当这些包合物暴露于其他气态客体分子时，观察到伴随相变的客体交换。该过程的第一步是缓慢的客体交换，直到达到40-50%的交换，第二步是急剧气体交换的相变（90%）。

X-Ray crystal analysis of macrocyclic heterocyclophane(N,N^1,N^<11>,N^<111> -tetramethyl-2,11,20,29-tetraaza-[3.3.3.3]paracyclophane[1]) inclusion compounds with benzene, pyridine, CHCl_3, CH_3CN, CO_2, CH_2Cl_2 and CH_2BrCl was undertaken. The crystals of these inclusion compounds show guest dependent polymorphism and are classified as follows: l:benzene(P2_l,Z=4),l:pyridine (Pl,Z=l), l:CHCl_3 (C2, Z=2), l:CH_3CN and l:CO_2 (C2/c, Z=4), and l:CH_2Cl_2 and l:CH_2BrCl (C2/c, Z=8). In these crystalline inclusion compounds,l exists as 'R'-conformer of 'S'-conformer since the macrocyclic conformation of l is frozen in solid state. l is ftacked along the b-axis to form the molecular column which accomodate guest molecules l:l ratio. One molecular column is chiral because the column consistes of all'R'-or all 'S'-conformers of l. The chiral crystals consist of all 'R'-or all 'S'-column, while racemic crystals consist of both 'R'- and 'S'-column. The five different crystal structures can be interpreted from the viewpoint of the packing mode of the columns. The column arrangement is greatly related to the tilt angle of benzene ring in l. This angle depends on the size and shape of the guest molecule. The macrocyclic conformation(C_<2v>) of the uncomplexed l is different from that (C_4 of the complexed l. The conformational analysis of l by nolecular mechanics calculation shows that l has six stable conformation including enantiomer(the difference between maximum and minimum steric energy is 2.3 kcal/mol), suggesting the free interconversion of l among these six conformers in solution. The guest exchange accompanying phase transition was observed when these inclusion compounds were exposed to other gaseous guest molecules. The first step of this process is slow guest exchange until 40-50% exchange is reached and the second step is phase transition with steep gas exchange(90%).