Toward High‐Generation Rotaxane Dendrimers That Incorporate a Ring Component on Every Branch: Noncovalent Synthesis of a Dendritic [10]Pseudorotaxane with 13 Molecular Components |
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Authors: | Soo‐Young Kim Dr Young?Ho Ko Dr Jae?Wook Lee Dr Shigeru Sakamoto Dr Kentaro Yamaguchi Prof?Dr Kimoon Kim Prof?Dr |
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Institution: | 1. National Creative Research Initiative Center for Smart Supramolecules and Department of Chemistry, Pohang University of Science and Technology, San 31 Hyojadong, Pohang 790‐784, Republic of Korea, Fax: (+82)?54‐279‐8129;2. Current address: Department of Chemistry, Dong‐A University, 840 Hadandong, Busan 604‐714, Republic of Korea;3. Laboratory of Analytical Chemistry and Department of Pharmaceutical Technology, Faculty of Pharmaceutical Sciences at Kawaga Campus, Tokushima Bunri University, Shido, Sanuki‐city, Kagawa 769‐2193, Japan |
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Abstract: | By taking advantage of the fact that cucurbit6]uril (CB6]) forms exceptionally stable host–guest complexes with protonated amines, and that its homologue CB8] can encapsulate a pair of electron‐rich and electron‐deficient guest molecules to form a stable 1:1:1 complex, we synthesized a novel dendritic 10]pseudorotaxane, or second‐generation rotaxane dendrimer (from a topological point of view), in which 13 molecular components are held together by noncovalent interactions. A triply branched molecule containing an electron‐deficient bipyridinium unit on each branch formed a branched 4]pseudorotaxane with 3 equivalents of CB8]. Addition of 3 equivalents of 2,6‐dihydroxynaphthalene produced a first‐generation rotaxane dendrimer, which was characterized by NMR spectroscopy and CSI‐MS. The reaction of the branched 4]pseudorotaxane with 3 equivalents of a triply branched molecule that has an electron‐donor unit at one arm and CB6]‐containing units at the other two gave the dendritic 10]pseudorotaxane, the structure of which was confirmed by NMR spectroscopy, UV/Vis titration experiments, and CSI‐MS. |
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Keywords: | charge transfer dendrimers interlocked molecules rotaxanes supramolecular chemistry |
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