Achieving Strong Positive Cooperativity through Activating Weak Non‐Covalent Interactions |
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Authors: | Yan‐Long Ma Dr Hua Ke Dr Arto Valkonen Prof Kari Rissanen Prof Wei Jiang |
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Institution: | 1. Department of Chemistry, South University of Science and Technology of China, Shenzhen, China;2. Institute of Chinese Medical Science, University of Macau, Macau, China;3. Department of Chemistry, University of Jyvaskyla, Nanoscience Center, Jyvaskyla, Finland |
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Abstract: | Positive cooperativity achieved through activating weak non‐covalent interactions is common in biological assemblies but is rarely observed in synthetic complexes. Two new molecular tubes have been synthesized and the syn isomer binds DABCO‐based organic cations with high orientational selectivity. Surprisingly, the ternary complex with two hosts and one guest shows a high cooperativity factor (α=580), which is the highest reported for synthetic systems without involving ion‐pairing interactions. The X‐ray single‐crystal structure revealed that the strong positive cooperativity likely originates from eight C?H???O hydrogen bonds between the two head‐to‐head‐arranged syn tube molecules. These relatively weak hydrogen bonds were not observed in the free hosts and only emerged in the complex. Furthermore, this complex was used as a basic motif to construct a robust 2+2] cyclic assembly, thus demonstrating its potential in molecular self‐assembly. |
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Keywords: | cooperativity host– guest chemistry macrocycles self-assembly supramolecular chemistry |
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