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 - THES A1 - Rest, Christina T1 - Self-assembly of amphiphilic oligo(phenylene ethynylene)-based (bi)pyridine ligands and their Pt(II) and Pd(II) complexes T1 - Selbstorganisation von amphiphilen oligo(phenylenethinylen)-basierten (Bi)pyridin-Liganden und ihrer Pt(II) und Pd(II) Komplexe N2 - The presented work in the field of supramolecular chemistry describes the synthesis and detailed investigation of (bi)pyridine-based oligo(phenylene ethynylene) (OPE) amphiphiles, decorated with terminal glycol chains. The metal-ligating property of these molecules could be exploited to coordinate to Pd(II) and Pt(II) metal ions, respectively, resulting in the creation of novel metallosupramolecular π-amphiphiles of square-planar geometry. The focus of the presented studies is on the self-assembly behaviour of the OPE ligands and their corresponding metal complexes in polar and aqueous environment. In this way, the underlying aggregation mechanism (isodesmic or cooperative) is revealed and the influence of various factors on the self-assembly process in supramolecular systems is elucidated. In this regard, the effect of the molecular design of the ligand, the coordination to a metal centre as well as the surrounding medium, the pH value and temperature is investigated. N2 - Die vorliegende Arbeit auf dem Gebiet der Supramolekularen Chemie beschäftigt sich mit der Synthese und detaillierten Untersuchung von (bi)pyridin-basierten Oligo(phenylenethinylen) (OPE)-Amphiphilen mit endständigen Glykolketten. Die komplexierende Eigenschaft dieser Moleküle wurde ausgenutzt um sie an Pd(II) bzw. Pt(II) Metallionen zu koordinieren, wobei neuartige metallosupramolekulare π-Amphiphile von quadratisch-planarer Geometrie entstehen. Das Hauptaugenmerk der beschriebenen Studien liegt auf der Selbstorganisation der OPE-Liganden und ihrer Metallkomplexe in polarer und wässriger Umgebung. Dabei wurde der zu Grunde liegende Aggregationsmechanismus (isodesmisch oder kooperativ) bestimmt und der Einfluss verschiedener Faktoren auf den Selbstorganisationsprozess in supramolekularen Systemen aufzeigt. Neben dem Effekt des Moleküldesigns des Liganden und dessen Koordination an ein Metallzentrum wird auch der des umgebenden Mediums, des pH-Wertes sowie der Temperatur erläutert. KW - Supramolekulare Chemie KW - Selbstorganisation KW - Kooperativität KW - Aggregat KW - Amphiphile Verbindungen KW - cooperativity KW - non-covalent interactions KW - (bi)pyridine-based ligand KW - oligo(phenylene ethynylene) (OPE) KW - self-assembly KW - metallosupramolecular π-amphiphiles KW - Aggregation Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-133248 ER - TY - JOUR A1 - Rest, Christina A1 - Mayoral, María José A1 - Fernández, Gustavo T1 - Aqueous Self-Sorting in Extended Supramolecular Aggregates JF - International Journal of Molecular Sciences N2 - Self-organization and self-sorting processes are responsible for the regulation and control of the vast majority of biological processes that eventually sustain life on our planet. Attempts to unveil the complexity of these systems have been devoted to the investigation of the binding processes between artificial molecules, complexes or aggregates within multicomponent mixtures, which has facilitated the emergence of the field of self-sorting in the last decade. Since, artificial systems involving discrete supramolecular structures, extended supramolecular aggregates or gel-phase materials in organic solvents or—to a lesser extent—in water have been investigated. In this review, we have collected diverse strategies employed in recent years to construct extended supramolecular aggregates in water upon self-sorting of small synthetic molecules. We have made particular emphasis on co-assembly processes in binary mixtures leading to supramolecular structures of remarkable complexity and the influence of different external variables such as solvent and concentration to direct recognition or discrimination processes between these species. The comprehension of such recognition phenomena will be crucial for the organization and evolution of complex matter. KW - co-aggregation KW - self-sorting KW - supramolecular chemistry KW - self-assembly Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-129435 VL - 14 IS - 1 ER -