TY - JOUR A1 - Dostál, Jakub A1 - Fennel, Franziska A1 - Koch, Federico A1 - Herbst, Stefanie A1 - Würthner, Frank A1 - Brixner, Tobias T1 - Direct observation of exciton–exciton interactions JF - Nature Communications N2 - Natural light harvesting as well as optoelectronic and photovoltaic devices depend on efficient transport of energy following photoexcitation. Using common spectroscopic methods, however, it is challenging to discriminate one-exciton dynamics from multi-exciton interactions that arise when more than one excitation is present in the system. Here we introduce a coherent two-dimensional spectroscopic method that provides a signal only in case that the presence of one exciton influences the behavior of another one. Exemplarily, we monitor exciton diffusion by annihilation in a perylene bisimide-based J-aggregate. We determine quantitatively the exciton diffusion constant from exciton–exciton-interaction 2D spectra and reconstruct the annihilation-free dynamics for large pump powers. The latter enables for ultrafast spectroscopy at much higher intensities than conventionally possible and thus improves signal-to-noise ratios for multichromophore systems; the former recovers spatio–temporal dynamics for a broad range of phenomena in which exciton interactions are present. KW - energy transfer KW - self-assembly KW - optical spectroscopy Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-226271 VL - 9 ER - TY - THES A1 - Mahlmeister, Bernhard T1 - Twisted Rylene Bisimides for Organic Solar Cells and Strong Chiroptical Response in the Near Infrared T1 - Kernverdrillte Rylenbisimide für organische Solarzellen und starke chirooptische Eigenschaften im Nahinfrarot N2 - The chirality of the interlocked bay-arylated perylene motif is investigated upon its material prospect and the enhancement of its chiroptical response to the NIR spectral region. A considerable molecular library of inherently chiral perylene bisimides (PBIs) was utilized as acceptors in organic solar cells to provide decent device performances and insights into the structure-property relationship of PBI materials within a polymer blend. For the first time in the family of core-twisted PBIs, the effects of enantiopurity on the device performance was thoroughly investigated. The extraordinary structural sensitivity of CD spectroscopy served as crucial analytical tool to bridge the highly challenging gap between molecular properties and device analytics by proving the excitonic chirality of a helical PBI dimer. The chirality of this perylene motif could be further enhanced on a molecular level by both the expansion and the enhanced twisting of the π-scaffold to achieve a desirable strong chiroptical NIR response introducing a new family of twisted QBI-based nanoribbons. These achievements could be substantially further developed by expanding this molecular concept to a supramolecular level. The geometrically demanding supramolecular arrangement necessary for the efficient excitonic coupling was carefully encoded into the molecular design. Accordingly, the QBIs could form the first J-type aggregate constituting a fourfold-stranded superhelix of a rylene bisimide with strong excitonic chirality. Therefore, this thesis has highlighted the mutual corroboration of experimental and theoretical data from the molecular to the supramolecular level. It has demonstrated that for rylene bisimide dyes, the excitonic contribution to the overall chiroptical response can be designed and rationalized. This can help to pave the way for new organic functional materials to be used for chiral sensing or chiral organic light-emitting devices. N2 - Die Chiralität des verzahnten Bucht-arylierten Perylenmotivs wurde im Hinblick auf seine Materialanwendung sowie die Verstärkung seiner chiroptischen Eigenschaften im NIR-Spektralbereich untersucht. Eine umfangreiche Molekülbibliothek von inhärent chiralen PBIs wurde als NFAs in OSCs verwendet, um sowohl gute Solarzelleneffizienzen sowie Einblicke in die Struktur-Eigenschafts-Beziehung von PBI Materialien innerhalb einer Polymermischung zu erhalten. Zum ersten Mal wurden für kernverdrillte PBIs die Auswirkungen der Enantiomerenreinheit auf die Effizienz von organischen Dünnfilmbauteilen untersucht. Die außerordentliche strukturelle Empfindlichkeit der CD Spektroskopie diente als entscheidendes Analysewerkzeug, um die hoch anspruchsvolle Lücke zwischen der Analytik molekularer Eigenschaften und der Bauteilanalytik zu schließen, indem die exzitonische Chiralität eines helikalen PBI-Dimers nachgewiesen wurde. Die Chiralität dieses Perylenmotivs konnte auf molekularer Ebene weiter verstärkt werden, indem das π-Gerüst sowohl erweitert als auch stärker verdrillt wurde, um wünschenswert starke chiroptische Eigenschaften im NIR-Bereich zu erzielen und so eine neue Molekülfamilie kernverdrillter QBIs zu definieren. Diese Errungenschaften konnten durch die Ausweitung dieses molekularen Konzepts auf eine supramolekulare Ebene noch erheblich weiterentwickelt werden. Die geometrisch anspruchsvolle supramolekulare Anordnung, die für die effiziente exzitonische Kopplung erforderlich ist, wurde sorgfältig in das molekulare Design kodiert. Dementsprechend stellt das präsentierte QBI in seiner vierfach versetzt gestapelten Superhelix das erste Rylenbisimid-J-Aggregat dar, welches eine starke exzitonische Chiralität zeigt. Somit hat die Arbeit hat die gegenseitige Bestätigung von experimentellen und theoretischen Daten von der molekularen bis hin zur supramolekularen Ebene herausgestellt und gezeigt, dass für Rylenbisimid-Farbstoffe der exzitonische Beitrag zu den chiroptischen Eigenschaften konzipiert, synthetisch realisiert und quantenmechanisch verstanden werden kann. Dies kann den Weg für neue organische Funktionsmaterialien ebnen, die für chirale Sensoren oder Licht emittierende Bauteile verwendet werden können. KW - Molekül KW - Chiralität KW - Exziton KW - Organische Solarzelle KW - Supramolekulare Chemie KW - organic solar cell KW - non-fullerene acceptor KW - perylene bisimide KW - quaterrylene bisimide KW - inherent chirality KW - excitonic chirality KW - supramolecular chemistry KW - self-assembly KW - near infrared chirality Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-346106 ER - TY - JOUR A1 - Menekse, Kaan A1 - Mahl, Magnus A1 - Albert, Julius A1 - Niyas, M. A. A1 - Shoyama, Kazutaka A1 - Stolte, Matthias A1 - Würthner, Frank T1 - Supramolecularly Engineered Bulk‐Heterojunction Solar Cells with Self‐Assembled Non‐Fullerene Nanographene Tetraimide Acceptors JF - Solar RRL N2 - A series of novel imide‐functionalized C\(_{64}\) nanographenes is investigated as acceptor components in organic solar cells (OSCs) in combination with donor polymer PM6. These electron‐poor molecules either prevail as a monomer or self‐assemble into dimers in the OSC active layer depending on the chosen imide substituents. This allows for the controlled stacking of electron‐poor and electron‐rich π–scaffolds to establish a novel class of non‐fullerene acceptor materials to tailor the bulk‐heterojunction morphology of the OSCs. The best performance is observed for derivatives that are able to self‐assemble into dimers, reaching power conversion efficiencies of up to 7.1%. KW - nanographene KW - non-fullerene acceptors KW - organic solar cells KW - polycyclic aromatic hydrocarbons KW - self-assembly Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-312099 VL - 7 IS - 2 ER - TY - JOUR A1 - Hecht, Markus A1 - Leowanawat, Pawaret A1 - Gerlach, Tabea A1 - Stepanenko, Vladimir A1 - Stolte, Matthias A1 - Lehmann, Matthias A1 - Würthner, Frank T1 - Self‐Sorting Supramolecular Polymerization: Helical and Lamellar Aggregates of Tetra‐Bay‐Acyloxy Perylene Bisimide JF - Angewandte Chemie International Edition N2 - A new perylene bisimide (PBI), with a fluorescence quantum yield up to unity, self‐assembles into two polymorphic supramolecular polymers. This PBI bears four solubilizing acyloxy substituents at the bay positions and is unsubstituted at the imide position, thereby allowing hydrogen‐bond‐directed self‐assembly in nonpolar solvents. The formation of the polymorphs is controlled by the cooling rate of hot monomer solutions. They show distinctive absorption profiles and morphologies and can be isolated in different polymorphic liquid‐crystalline states. The interchromophoric arrangement causing the spectral features was elucidated, revealing the formation of columnar and lamellar phases, which are formed by either homo‐ or heterochiral self‐assembly, respectively, of the atropoenantiomeric PBIs. Kinetic studies reveal a narcissistic self‐sorting process upon fast cooling, and that the transformation into the heterochiral (racemic) sheetlike self‐assemblies proceeds by dissociation via the monomeric state. KW - liquid crystals KW - noncovalent interactions KW - self-assembly KW - structure elucidation KW - supramolecular chemistry Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-224586 VL - 59 IS - 39 SP - 17084 EP - 17090 ER - TY - JOUR A1 - Syamala, Pradeep P. N. A1 - Würthner, Frank T1 - Modulation of the Self‐Assembly of π‐Amphiphiles in Water from Enthalpy‐ to Entropy‐Driven by Enwrapping Substituents JF - Chemistry – A European Journal N2 - Depending on the connectivity of solubilizing oligoethylene glycol (OEG) side chains to the π‐cores of amphiphilic naphthalene and perylene bisimide dyes, self‐assembly in water occurs either upon heating or cooling. Herein, we show that this effect originates from differences in the enwrapping capability of the π‐cores by the OEG chains. Rylene bisimides bearing phenyl substituents with three OEG chains attached directly to the hydrophobic π‐cores are strongly sequestered by the OEG chains. These molecules self‐assemble at elevated temperatures in an entropy‐driven process according to temperature‐ and concentration‐dependent UV/Vis spectroscopy and calorimetric dilution studies. In contrast, for rylene bisimides in which phenyl substituents with three OEG chains are attached via a methylene spacer, leading to much weaker sequestration, self‐assembly originates upon cooling in an enthalpy‐driven process. Our explanation for this controversial behavior is that the aggregation in the latter case is dictated by the release of “high energy water” from the hydrophobic π‐surfaces as well as dispersion interactions between the π‐scaffolds which drive the self‐assembly in an enthalpically driven process. In contrast, for the former case we suggest that in addition to the conventional explanation of a dehydration of hydrogen‐bonded water molecules from OEG units it is in particular the increase in conformational entropy of back‐folded OEG side chains upon aggregation that provides the pronounced gain in entropy that drives the aggregation process. Thus, our studies revealed that a subtle change in the attachment of solubilizing substituents can switch the thermodynamic signature for the self‐assembly of amphiphilic dyes in water from enthalpy‐ to entropy‐driven. KW - amphiphilic dyes KW - self-assembly KW - thermodynamics KW - OEG chains KW - π-conjugated systems Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-218107 VL - 26 IS - 38 SP - 8426 EP - 8434 ER - TY - JOUR A1 - Meza-Chincha, Ana-Lucia A1 - Lindner, Joachim O. A1 - Schindler, Dorothee A1 - Schmidt, David A1 - Krause, Ana-Maria A1 - Röhr, Merle I. S. A1 - Mitrić, Roland A1 - Würthner, Frank T1 - Impact of substituents on molecular properties and catalytic activities of trinuclear Ru macrocycles in water oxidation N2 - Herein we report a broad series of new trinuclear supramolecular Ru(bda) macrocycles bearing different substituents at the axial or equatorial ligands which enabled investigation of substituent effects on the catalytic activities in chemical and photocatalytic water oxidation. Our detailed investigations revealed that the activities of these functionalized macrocycles in water oxidation are significantly affected by the position at which the substituents were introduced. Interestingly, this effect could not be explained based on the redox properties of the catalysts since these are not markedly influenced by the functionalization of the ligands. Instead, detailed investigations by X-ray crystal structure analysis and theoretical simulations showed that conformational changes imparted by the substituents are responsible for the variation of catalytic activities of the Ru macrocycles. For the first time, macrocyclic structure of this class of water oxidation catalysts is unequivocally confirmed and experimental indication for a hydrogen-bonded water network present in the cavity of the macrocycles is provided by crystal structure analysis. We ascribe the high catalytic efficiency of our Ru(bda) macrocycles to cooperative proton abstractions facilitated by such a network of preorganized water molecules in their cavity, which is reminiscent of catalytic activities of enzymes at active sites. KW - water oxidation KW - self-assembly KW - solar fuels KW - supramolecular materials KW - catalysis Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-204653 UR - https://doi.org/10.1039/D0SC01097A SN - 2041-6539 ER - TY - JOUR A1 - Grande, Vincenzo A1 - Soberats, Bartolome A1 - Herbst, Stefanie A1 - Stepanenko, Vladimir A1 - Würthner, Frank T1 - Hydrogen-bonded perylene bisimide J-aggregate aqua material N2 - A new twelvefold methoxy-triethyleneglycol-jacketed tetraphenoxy-perylene bisimide (MEG-PBI) amphiphile was synthesized that self-assembles into two types of supramolecular aggregates in water: red-coloured aggregates of low order and with weak exciton coupling among the PBIs and blue-coloured strongly coupled J-aggregates consisting of a highly ordered hydrogen-bonded triple helix of PBIs. At room temperature this PBI is miscible with water at any proportions which enables the development of robust dye aggregates in solution, in hydrogel states and in lyotropic liquid crystalline states. In the presence of 60–95 wt% water, self-standing coloured hydrogels exhibit colour changes from red to blue accompanied by a fluorescence light-up in the far-red region upon heating in the range of 30–50 °C. This phenomenon is triggered by an entropically driven temperature-induced hydrogen-bond-directed slipped stacking arrangement of the MEG-PBI chromophores within structurally well-defined J-aggregates. This versatile aqua material is the first example of a stable PBI J-aggregate in water. We anticipate that this study will open a new avenue for the development of biocompatible functional materials based on self-assembled dyes and inspire the construction of other hydrogen-bonded supramolecular materials in the highly competitive solvent water. KW - self-assembly KW - dyes KW - aqua material Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-204715 UR - https://doi.org/10.1039/C8SC02409J SN - 2041-6539 VL - 9 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 - 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 - THES A1 - Shao, Changzhun T1 - Programming Self-assembly: Formation of Discrete Perylene Bisimide Aggregates T1 - Steuerung der Selbstassemblierung: Aufbau der diskreten Perylenbisimid-Aggregaten N2 - The objective of this thesis focuses on the development of strategies for precise control of perylene bisimide (PBI) self-assembly and the in-depth elucidation of structural and optical features of discrete PBI aggregates by means of NMR and UV/Vis spectroscopy. The strategy for discrete dimer formation of PBIs is based on delicate steric control that distinguishes the two facets of the central perylene surface. The strategy applied in this thesis for accessing discrete PBI quadruple and further oligomeric stacks relies on backbone-directed PBI self-assembly. For this purpose, two tweezer-like PBI dyads bearing the respective rigid backbones, diphenylacetylene (DPA) and diphenylbutydiyne (DPB), were synthesized. The distinct aggregation behavior of these structurally similar PBI dyads can be ascribed to the intramolecular distance between the two PBI chromophores imparted by the DPA and DPB spacers. N2 - Das Ziel dieser Arbeit ist die Entwicklung von Strategien für die präzise Steuerung der PBI-Selbstorganisation sowie die gründliche Aufklärung der strukturellen und optischen Eigenschaften von diskreten PBI-Aggregaten mittels NMR- und UV/Vis-Spektroskopie. Die Strategie der diskreten Dimerbildung von PBIs ist auf der empfindlichen sterischen Kontrolle begründet, die eine Differenzierung der beiden Facetten der zentralen Perylenoberfläche ermöglicht. Um diskrete vierfache und höhere oligomere PBI-Stapel zu erhalten, behilft sich die vorliegende Arbeit der PBI-Selbstorganisation, die durch ein Rückgrat vermittelt wird. Zu diesem Zweck wurden zwei pinzettenartige PBI-Dyaden synthetisiert, die die starren Rückgrate Diphenylacetylen (DPA) bzw. Diphenylbutydiyn (DPB) tragen (Abbildung 2). Das unterschiedliche Aggregationsverhalten dieser strukturell ähnlichen PBI-Dyaden kann den verschiedenen intramolekularen Abständen der beiden PBI-Chromophore zugeschrieben werden, die durch DPA bzw. DPB als Abstandshalter vorgegeben werden. KW - Farbstoff KW - perylene bisimide KW - self-assembly KW - dimer KW - Perylenderivate KW - Selbstorganisation Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-69298 ER -