Clathrate formation of Diels-Alder adduct of phencyclone and acenaphthylene. Key role of CH/蟺 and bidentate CH/O interactions of the phenanthrene ring in聽construction of host framework

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• 作者：Masaki Abe^a ; Masashi Eto^a ; ^{meto@ph.sojo-u.ac.jp} ; Koki Yamaguchi^a ; Masatoshi Yamasaki^a ; Junichi Misaka^a ; Yasuyuki Yoshitake^a ; Masami Otsuka^b ; Kazunobu Harano^a
• 关键词：CH/蟺 interaction ; CH/O interaction ; Phencyclone ; PM6 calculation
• 刊名：Tetrahedron
• 出版年：2012
• 期刊代码：107_00404020
• 类别：ch
• 出版时间：6 May, 2012
• 卷：68
• 期：18
• 页码：3566-3576
• 文件大小：2381 K

摘要

Two clathrate hosts (3a and 3b) were synthesized via the Diels-Alder reaction of phencyclone (1a) and tetracyclone (1b) with acenaphthylene (2), and the clathrate formation properties of these hosts towards a variety of organic guests were investigated. In the presence of aprotic solvents (i.e., aromatic, ketonic and etheric solvents), host 3a formed inclusion complexes with a 2:1 stoichiometric host/guest ratio, whereas 3b primarily formed 1:1 complexes. The desolvation temperatures of the 3a路guest complexes were extremely high in comparison to the boiling points of the pure guest liquids and were also much higher than those of the corresponding 3b路guest complexes, which contain the conformationally flexible stilbene moiety. Structural analyses of the 3a路guest complexes (i.e., 3a路benzene, 3a路toluene, 3a路1,4-dioxane, 3a路acetone and 3a路pentan-3-one) show that the aromatic CH/蟺 (edge-to-face) interactions between phenanthrene and the acenaphthene ring as well as the interaction of the 鈥榖identate鈥?CH/O hydrogen bond between the phenanthrene-ring hydrogen and the bridged carbonyl oxygen play a key role in the construction of the characteristic host 鈥榗olumn鈥?structures. The guest molecule of the 3a路benzene complex is held between the stacking columns by aromatic CH/蟺 interactions of the acenaphthene rings of adjacent host molecules. The stable clathrate formation of 3a is discussed based on X-ray structural analyses of six clathrates and PM6 molecular orbital calculations for the clathration model of 3a路benzene.