TY  - JOUR
A1  - Rest, Christina
A1  - Philips, Divya Susan
A1  - Dünnebacke, Torsten
A1  - Sutar, Papri
A1  - Sampedro, Angel
A1  - Droste, Jörn
A1  - Stepanenko, Vladimir
A1  - Hansen, Michael Ryan
A1  - Albuquerque, Rodrigo Q.
A1  - Fernández, Gustavo
T1  - Tuning Aqueous Supramolecular Polymerization by an Acid‐Responsive Conformational Switch
JF  - Chemistry – A European Journal
N2  - Besides their widespread use in coordination chemistry, 2,2’‐bipyridines are known for their ability to undergo cis–trans conformational changes in response to metal ions and acids, which has been primarily investigated at the molecular level. However, the exploitation of such conformational switching in self‐assembly has remained unexplored. In this work, the use of 2,2’‐bipyridines as acid‐responsive conformational switches to tune supramolecular polymerization processes has been demonstrated. To achieve this goal, we have designed a bipyridine‐based linear bolaamphiphile, 1, that forms ordered supramolecular polymers in aqueous media through cooperative aromatic and hydrophobic interactions. Interestingly, addition of acid (TFA) induces the monoprotonation of the 2,2’‐bipyridine moiety, leading to a switch in the molecular conformation from a linear (trans) to a V‐shaped (cis) state. This increase in molecular distortion along with electrostatic repulsions of the positively charged bipyridine‐H\(^{+}\) units attenuate the aggregation tendency and induce a transformation from long fibers to shorter thinner fibers. Our findings may contribute to opening up new directions in molecular switches and stimuli‐responsive supramolecular materials.
KW  - acid-sensitive
KW  - amphiphilic systems
KW  - π-conjugated systems
KW  - noncovalent interactions
KW  - self-assembly
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-218118
VL  - 26
IS  - 44
SP  - 10005
EP  - 10013
ER  - 
TY  - JOUR
A1  - Bäumer, Nils
A1  - Kartha, Kalathil K.
A1  - Allampally, Naveen Kumar
A1  - Yagai, Shiki
A1  - Albuquerque, Rodrigo Q.
A1  - Fernández, Gustavo
T1  - Kontrolle über Selbstassemblierung durch Ausnutzung von Koordinationsisomerie
JF  - Angewandte Chemie
N2  - Hierin wird die inhärente geometrische Isomerie eines PtII Komplexes als neues Werkzeug zur Kontrolle von supramolekularen Assemblierungsprozessen ausgenutzt. Bestrahlung mit UV‐Licht sowie die sorgfältige Auswahl des verwendeten Lösungsmittels, der Temperatur und Konzentration führen zu einer regelbaren Koordinationsisomerie. Dies ermöglicht ein vollständig reversibles Schalten zwischen zwei definierten aggregierten Spezies (1D Fasern ↔ 2D Lamellen) mit unterschiedlichem photoresponsivem Verhalten. Unsere Erkenntnisse erweitern nicht nur die Reichweite von Koordinationsisomerie, sondern eröffnen auch aufregende Möglichkeiten zur Entwicklung neuartiger stimuliresponsiver Materialien.
KW  - Koordinationsisomerie
KW  - Photoresponsives Verhalten
KW  - Selbstassemblierung
KW  - Supramolekulare Polymere
KW  - π-Konjugierte Systeme
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-212176
VL  - 131
IS  - 44
SP  - 15772
EP  - 15776
ER  -