Hydrogen‐Bond‐Driven Controlled Molecular Marriage in Covalent Cages |
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Authors: | Koushik Acharyya Prof?Dr Partha Sarathi Mukherjee |
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Institution: | Department of Inorganic & Physical Chemistry, Indian Institution of Science, Bangalore 560 012 (India), Fax: (+91)?8023601552 |
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Abstract: | A supramolecular approach that uses hydrogen‐bonding interaction as a driving force to accomplish exceptional self‐sorting in the formation of imine‐based covalent organic cages is discussed. Utilizing the dynamic covalent chemistry approach from three geometrically similar dialdehydes ( A , B , and D ) and the flexible triamine tris(2‐aminoethyl)amine ( X ), three new 3+2] self‐assembled nanoscopic organic cages have been synthesized and fully characterized by various techniques. When a complex mixture of the dialdehydes and triamine X was subjected to reaction, it was found that only dialdehyde B (which has OH groups for H‐bonding) reacted to form the corresponding cage B3X2 selectively. Surprisingly, the same reaction in the absence of aldehyde B yielded a mixture of products. Theoretical and experimental investigations are in complete agreement that the presence of the hydroxyl moiety adjacent to the aldehyde functionality in B is responsible for the selective formation of cage B3X2 from a complex reaction mixture. This spectacular selection was further analyzed by transforming a nonpreferred (non‐hydroxy) cage into a preferred (hydroxy) cage B3X2 by treating the former with aldehyde B . The role of the H‐bond in partner selection in a mixture of two dialdehydes and two amines has also been established. Moreover, an example of unconventional imine bond metathesis in organic cage‐to‐cage transformation is reported. |
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Keywords: | aldehydes cage compounds hydrogen bonds metathesis self‐sorting |
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