Anomalous Inclusion Behavior Shown by a Thia-Bridged Diquinoline Derivative

The sulfur-bridged compound 6,7,14,15-tetrahydro-6,14-thiacycloocta[1,2-b:5,6-b′]diquinoline (11) yields a solvent-free crystal form but also produces lattice inclusion compounds containing chloroform, water, and methanol. This latter behavior is in marked contrast to the noninclusion characteristics shown by its corresponding oxygen- and methano-bridged analogues. X-ray structures of the three different crystal types formed by 11 reveal that all contain a two-molecule repeat unit in which the S atom of the first is located within the V-shaped cleft of the second. This assembly is reminiscent of a ball and socket joint, and the adoption of this motif is the root cause of the unexpected solid-state inclusion properties shown by 11.

硫桥化合物6,7,14,15-四氢-6,14-硫杂环辛并[1,2-b:5,6-b′]二喹啉（11）可形成无溶剂晶型，同时也能生成包含氯仿、水与甲醇的晶格包合物（lattice inclusion compound）。该化合物的这一包合行为，与其对应的氧桥与亚甲基桥类似物所展现的无包合特性形成鲜明对比。对11所形成的三种不同晶型进行的X射线晶体结构（X-ray structure）分析显示，所有晶型均包含双分子重复单元，其中第一个分子的硫原子恰好位于第二个分子的V形凹槽内。这种分子组装模式类似球窝接头（ball and socket joint），而该结构基序的采用正是导致11表现出反常固态包合特性的根本原因。