Stimuli‐Responsive Molecular Duplexes Displaying Duplex‐to‐Duplex Switching

Abstract Synthetic duplexes with high stabilities have promising potential for mimicking biomolecular functions and developing supramolecular smart materials. Herein, we describe the synthesis and stimuli‐responsive properties of molecular duplexes derived from indolocarbazole–pyridine (I−P) oligome...

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Published in:Angewandte Chemie International Edition 2024-08, p.e202410884
Main Authors: Lee, Seungwon, Song, Geunmoo, Jeong, Kyu‐Sung
Format: Article
Language:English
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Summary:Abstract Synthetic duplexes with high stabilities have promising potential for mimicking biomolecular functions and developing supramolecular smart materials. Herein, we describe the synthesis and stimuli‐responsive properties of molecular duplexes derived from indolocarbazole–pyridine (I−P) oligomers. These duplexes adopt nonclassical helical structures, stabilized by I−P hydrogen‐bonding pairs in anhydrous chlorinated solvents. Notably, the longest duplex 6 2 (11‐mer) 2 displays remarkable stability, forming twenty hydrogen bonds; its exchange energy barrier was determined to be Δ G ≠ =22.0 kcal ⋅ mol −1 at 75 °C in anhydrous (CDCl 2 ) 2 . Upon the addition of water, a hydrated duplex 6 2 (11‐mer) 2 ⊃10H 2 O was formed, with one water molecule inserted between each I−P hydrogen‐bonding pair. The Hill coefficient ( n ) for this process is 6.1, demonstrating extremely positive cooperativity. Conversely, the hydrated duplex 6 2 (11‐mer) 2 ⊃10H 2 O was completely converted into the original anhydrous duplex 6 2 (11‐mer) 2 when the temperature was increased. Interconversion between these two distinct duplexes can be repeatedly carried out by varying the temperature. Furthermore, reversible switching between hetero‐duplexes and homo‐duplexes was also demonstrated by controlling the temperature, with concomitant changes in the characteristic emission signals.
ISSN:1433-7851
1521-3773
1521-3773
DOI:10.1002/anie.202410884