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Achieving Strong Positive Cooperativity through Activating Weak Non‐Covalent Interactions
Author(s) -
Ma YanLong,
Ke Hua,
Valkonen Arto,
Rissanen Kari,
Jiang Wei
Publication year - 2018
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201711077
Subject(s) - cooperativity , hydrogen bond , chemistry , cooperative binding , molecule , covalent bond , crystallography , dabco , non covalent interactions , ternary complex , stereochemistry , ternary operation , binding site , octane , organic chemistry , biochemistry , computer science , programming language , enzyme
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.