@article{RestPhilipsDuennebackeetal.2020, author = {Rest, Christina and Philips, Divya Susan and D{\"u}nnebacke, Torsten and Sutar, Papri and Sampedro, Angel and Droste, J{\"o}rn and Stepanenko, Vladimir and Hansen, Michael Ryan and Albuquerque, Rodrigo Q. and Fern{\´a}ndez, Gustavo}, title = {Tuning Aqueous Supramolecular Polymerization by an Acid-Responsive Conformational Switch}, series = {Chemistry - A European Journal}, volume = {26}, journal = {Chemistry - A European Journal}, number = {44}, doi = {10.1002/chem.202001566}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-218118}, pages = {10005 -- 10013}, year = {2020}, abstract = {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.}, language = {en} } @article{BaeumerKarthaAllampallyetal.2019, author = {B{\"a}umer, Nils and Kartha, Kalathil K. and Allampally, Naveen Kumar and Yagai, Shiki and Albuquerque, Rodrigo Q. and Fern{\´a}ndez, Gustavo}, title = {Kontrolle {\"u}ber Selbstassemblierung durch Ausnutzung von Koordinationsisomerie}, series = {Angewandte Chemie}, volume = {131}, journal = {Angewandte Chemie}, number = {44}, doi = {10.1002/ange.201908002}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-212176}, pages = {15772 -- 15776}, year = {2019}, abstract = {Hierin wird die inh{\"a}rente geometrische Isomerie eines PtII Komplexes als neues Werkzeug zur Kontrolle von supramolekularen Assemblierungsprozessen ausgenutzt. Bestrahlung mit UV-Licht sowie die sorgf{\"a}ltige Auswahl des verwendeten L{\"o}sungsmittels, der Temperatur und Konzentration f{\"u}hren zu einer regelbaren Koordinationsisomerie. Dies erm{\"o}glicht ein vollst{\"a}ndig 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 er{\"o}ffnen auch aufregende M{\"o}glichkeiten zur Entwicklung neuartiger stimuliresponsiver Materialien.}, language = {de} }