From Packed “Sandwich” to “Russian Doll”: Assembly by Charge‐Transfer Interactions in Cucurbit[10]uril |
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| Authors: | Wanjun Gong Xiran Yang Peter Y Zavalij Prof Lyle Isaacs Dr Zhiyong Zhao Prof Simin Liu |
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| Affiliation: | 1. School of Chemistry and Chemical Engineering, Wuhan University of Science and Technology, Wuhan, P.R. China;2. Department of Chemistry and Biochemistry, University of Maryland, College Park, MD, USA;3. The State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan, P.R. China |
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| Abstract: | As the host possessing the largest cavity in the cucurbitn]uril (CBn]) family, CB10] has previously displayed unusual recognition and assembly properties with guests but much remains to be explored. Herein, we present the recognition properties of CB10] toward a series of bipyridinium guests including the tetracationic cyclophane known as blue box along with electron‐rich guests and detail the influence of encapsulation on the charge‐transfer interactions between guests. For the mono‐bipyridinium guest (methylviologen, MV 2+), CB10] not only forms 1:1 and 1:2 inclusion complexes, but also enhances the charge‐transfer interactions between methylviologen and dihydroxynaphthalene ( HN ) by mainly forming the 1:2:1 packed “sandwich” complex (CB10] ? 2 MV 2+ ?HN ). For guest 1 with two bipyridinium units, an interesting conformational switching from linear to “U” shape is observed by adding catechol to the solution of CB10] and the guest. For the tetracationic cyclophane‐blue box, CB10] forms a stable 1:1 inclusion complex; the two bipyridinium units tilt inside the cavity of CB10] according to the X‐ray crystal structure. Finally, a supramolecular “Russian doll” was built up by threading a guest through the cavities of both blue box and CB10]. |
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| Keywords: | charge-transfer interactions cucurbituril host– guest systems Russian dolls supramolecular chemistry |
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