Version 1
: Received: 26 October 2021 / Approved: 27 October 2021 / Online: 27 October 2021 (12:37:04 CEST)
Version 2
: Received: 17 January 2022 / Approved: 18 January 2022 / Online: 18 January 2022 (10:27:57 CET)
Frangville, P.; Kumar, S.; Gelbcke, M.; Van Hecke, K.; Meyer, F. Stimuli Responsive Materials Supported by Orthogonal Hydrogen and Halogen Bonding or I···Alkene Interaction. Molecules2021, 26, 7586.
Frangville, P.; Kumar, S.; Gelbcke, M.; Van Hecke, K.; Meyer, F. Stimuli Responsive Materials Supported by Orthogonal Hydrogen and Halogen Bonding or I···Alkene Interaction. Molecules 2021, 26, 7586.
Frangville, P.; Kumar, S.; Gelbcke, M.; Van Hecke, K.; Meyer, F. Stimuli Responsive Materials Supported by Orthogonal Hydrogen and Halogen Bonding or I···Alkene Interaction. Molecules2021, 26, 7586.
Frangville, P.; Kumar, S.; Gelbcke, M.; Van Hecke, K.; Meyer, F. Stimuli Responsive Materials Supported by Orthogonal Hydrogen and Halogen Bonding or I···Alkene Interaction. Molecules 2021, 26, 7586.
Abstract
Smart materials represent an elegant class of (macro)-molecules endowed with the ability to react to chemical/physical changes in the environment. Herein, we prepared new photo responsive azobenzenes possessing halogen bond donor groups. The X-ray structures of two molecules highlight supramolecular organizations governed by unusual noncovalent bonds. In azo dye I-azo-NO2, the nitro group is engaged in orthogonal H···O···I halogen and hydrogen bonding, linking the units in parallel undulating chains. As far as compound I-azo-NH-MMA is concerned, a non-centrosymmetric pattern is formed due to a very rare I···π interaction involving the alkene group supplemented by hydrogen bonds. The Cambridge Structural Database contains only four structures showing the same I···CH2=C contact. For all compounds, an 19F NMR spectroscopic analysis confirms the formation of halogen bonds in solution through a recognition process with chloride anion, and the reversible photo-responsiveness is demonstrated upon exposing a solution to UV light irradiation. Finally, the intermediate I-azo-NH2 also shows a pronounced color change due to pH variation. These azobenzenes are thereby attractive building blocks to design future multi-stimuli responsive materials for highly functional devices.
Copyright:
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Commenter: Franck Meyer
Commenter's Conflict of Interests: Author