Wide‐Ranging Host Capability of a PdII‐Linked M2L4 Molecular Capsule with an Anthracene Shell |
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Authors: | Norifumi Kishi Dr Zhiou Li Dr Yoshihisa Sei Prof?Dr Munetaka Akita Dr Kenji Yoza Prof?Dr Jay S Siegel Dr Michito Yoshizawa |
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Institution: | 1. Chemical Resources Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori‐ku, Yokohama 226‐8503 (Japan), Fax: (+81) 45‐924‐5230;2. Bruker AXS, 3‐9 Moriya‐cho, Kanagawa‐ku, Yokohama 221‐0022 (Japan);3. Organic Chemistry Institute, University of Zürich, Winterthurerstrasse 190, Zürich 8057 (Switzerland) |
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Abstract: | This article reports that an M2L4 molecular capsule is capable of encapsulating various neutral molecules in quantitative yields. The capsule was obtained as a single product by mixing a small number of components; two PdII ions and four bent bispyridine ligands containing two anthracene panels. Detailed studies of the host capability of the PdII‐linked capsule revealed that spherical (e.g., paracyclophane, adamantanes, and fullerene C60), planar (e.g., pyrenes and triphenylene), and bowl‐shaped molecules (e.g., corannulene) were encapsulated in the large spherical cavity, giving rise to 1:1 and 1:2 host–guest complexes, respectively. The volume of the encapsulated guest molecules ranged from 190 to 490 Å3. Within the capsule, the planar guests adopt a stacked‐dimer structure and the bowl‐shaped guests formed an unprecedented concave‐to‐concave capsular structure, which are fully shielded by the anthracene shell. Competitive binding experiments of the capsule with a set of the planar guests established a preferential binding series for pyrenes≈phenanthrene>triphenylene. Furthermore, the capsule showed the selective formation of an unusual ternary complex in the case of triphenylene and corannulene. |
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Keywords: | anthracene encapsulation host‐guest systems molecular recognition self‐assembly |
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