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 - Okuda, Takumi A1 - Lenz, Ann-Kathrin A1 - Seitz, Florian A1 - Vogel, Jörg A1 - Höbartner, Claudia T1 - A SAM analogue-utilizing ribozyme for site-specific RNA alkylation in living cells JF - Nature Chemistry N2 - Post-transcriptional RNA modification methods are in high demand for site-specific RNA labelling and analysis of RNA functions. In vitro-selected ribozymes are attractive tools for RNA research and have the potential to overcome some of the limitations of chemoenzymatic approaches with repurposed methyltransferases. Here we report an alkyltransferase ribozyme that uses a synthetic, stabilized S-adenosylmethionine (SAM) analogue and catalyses the transfer of a propargyl group to a specific adenosine in the target RNA. Almost quantitative conversion was achieved within 1 h under a wide range of reaction conditions in vitro, including physiological magnesium ion concentrations. A genetically encoded version of the SAM analogue-utilizing ribozyme (SAMURI) was expressed in HEK293T cells, and intracellular propargylation of the target adenosine was confirmed by specific fluorescent labelling. SAMURI is a general tool for the site-specific installation of the smallest tag for azide-alkyne click chemistry, which can be further functionalized with fluorophores, affinity tags or other functional probes. KW - Alkyltransferase Ribozyme SAMURI KW - Site-specific RNA labelling KW - bioorthogonal SAM analogue ProSeDMA KW - Chemical modification KW - RNA Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-328762 ER - TY - JOUR A1 - Brünnert, Daniela A1 - Seupel, Raina A1 - Goyal, Pankaj A1 - Bach, Matthias A1 - Schraud, Heike A1 - Kirner, Stefanie A1 - Köster, Eva A1 - Feineis, Doris A1 - Bargou, Ralf C. A1 - Schlosser, Andreas A1 - Bringmann, Gerhard A1 - Chatterjee, Manik T1 - Ancistrocladinium A induces apoptosis in proteasome inhibitor-resistant multiple myeloma cells: a promising therapeutic agent candidate JF - Pharmaceuticals N2 - The N,C-coupled naphthylisoquinoline alkaloid ancistrocladinium A belongs to a novel class of natural products with potent antiprotozoal activity. Its effects on tumor cells, however, have not yet been explored. We demonstrate the antitumor activity of ancistrocladinium A in multiple myeloma (MM), a yet incurable blood cancer that represents a model disease for adaptation to proteotoxic stress. Viability assays showed a potent apoptosis-inducing effect of ancistrocladinium A in MM cell lines, including those with proteasome inhibitor (PI) resistance, and in primary MM cells, but not in non-malignant blood cells. Concomitant treatment with the PI carfilzomib or the histone deacetylase inhibitor panobinostat strongly enhanced the ancistrocladinium A-induced apoptosis. Mass spectrometry with biotinylated ancistrocladinium A revealed significant enrichment of RNA-splicing-associated proteins. Affected RNA-splicing-associated pathways included genes involved in proteotoxic stress response, such as PSMB5-associated genes and the heat shock proteins HSP90 and HSP70. Furthermore, we found strong induction of ATF4 and the ATM/H2AX pathway, both of which are critically involved in the integrated cellular response following proteotoxic and oxidative stress. Taken together, our data indicate that ancistrocladinium A targets cellular stress regulation in MM and improves the therapeutic response to PIs or overcomes PI resistance, and thus may represent a promising potential therapeutic agent. KW - multiple myeloma KW - ancistrocladinium A KW - naphthylisoquinoline alkaloids KW - proteasome inhibitor resistance KW - RNA splicing KW - cellular stress response KW - proteasome subunit beta type-5 (PSMB5) KW - activating transcription factor 4 (ATF4) KW - ataxia teleagiectasia mutated (ATM) KW - H2A histone family member X (H2AX) Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-362887 SN - 1424-8247 VL - 16 IS - 8 ER - TY - JOUR A1 - Noll, Niklas A1 - Groß, Tobias A1 - Shoyama, Kazutaka A1 - Beuerle, Florian A1 - Würthner, Frank T1 - Folding‐Induced Promotion of Proton‐Coupled Electron Transfers via Proximal Base for Light‐Driven Water Oxidation JF - Angewandte Chemie International Edition N2 - Proton‐coupled electron‐transfer (PCET) processes play a key role in biocatalytic energy conversion and storage, for example, photosynthesis or nitrogen fixation. Here, we report a series of bipyridine‐containing di‐ to tetranuclear Ru(bda) macrocycles 2 C–4 C (bda: 2,2′‐bipyridine‐6,6′‐dicarboxylate) to promote O−O bond formation. In photocatalytic water oxidation under neutral conditions, all complexes 2 C–4 C prevail in a folded conformation that support the water nucleophilic attack (WNA) pathway with remarkable turnover frequencies of up to 15.5 s\(^{−1}\) per Ru unit respectively. Single‐crystal X‐ray analysis revealed an increased tendency for intramolecular π‐π stacking and preorganization of the proximal bases close to the active centers for the larger macrocycles. H/D kinetic isotope effect studies and electrochemical data demonstrate the key role of the proximal bipyridines as proton acceptors in lowering the activation barrier for the crucial nucleophilic attack of H\(_{2}\)O in the WNA mechanism. KW - artificial photosynthesis KW - folded macrocyles KW - homogeneous catalysis KW - photocatalysis KW - Ruthenium complexes Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-312020 VL - 62 IS - 7 ER - TY - INPR A1 - Fersch, Daniel A1 - Malý, Pavel A1 - Rühe, Jessica A1 - Lisinetskii, Victor A1 - Hensen, Matthias A1 - Würthner, Frank A1 - Brixner, Tobias T1 - Single-Molecule Ultrafast Fluorescence-Detected Pump–Probe Microscopy N2 - We introduce fluorescence-detected pump–probe microscopy by combining a wavelength-tunable ultrafast laser with a confocal scanning fluorescence microscope, enabling access to the femtosecond time scale on the micrometer spatial scale. In addition, we obtain spectral information from Fourier transformation over excitation pulse-pair time delays. We demonstrate this new approach on a model system of a terrylene bisimide (TBI) dye embedded in a PMMA matrix and acquire the linear excitation spectrum as well as time-dependent pump–probe spectra simultaneously. We then push the technique towards single TBI molecules and analyze the statistical distribution of their excitation spectra. Furthermore, we demonstrate the ultrafast transient evolution of several individual molecules, highlighting their different behavior in contrast to the ensemble due to their individual local environment. By correlating the linear and nonlinear spectra, we assess the effect of the molecular environment on the excited-state energy. KW - Fluoreszenz KW - Ultrafast spectroscopy KW - Single-molecule microscopy Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-313485 ER - TY - JOUR A1 - Brust, Felix A1 - Nagler, Oliver A1 - Shoyama, Kazutaka A1 - Stolte, Matthias A1 - Würthner, Frank T1 - Organic Light‐Emitting Diodes Based on Silandiol‐Bay‐Bridged Perylene Bisimides JF - Advanced Optical Materials N2 - Perylene bisimides (PBIs) are among the best fluorophores but have to be enwrapped for optoelectronic applications by large and heavy substituents to prevent their ππ‐stacking, which is known to accelerate non‐radiative decay processes in the solid state. Here, light‐weight di‐tert‐butylsilyl groups are introduced to bridge 1,12‐dihydroxy and 1,6,7,12‐tetrahydroxy PBIs to afford sublimable dyes for vacuum‐processed optoelectronic devices. For both new compounds, this substitution provides a twisted and shielded perylene π‐core whose, via OSiObridges, rigid structure affords well‐resolved absorption and emission spectra with strong fluorescence in solution, as well as in the solid state. The usefulness of these dyes for vacuum‐processed optoelectronic devices is demonstrated in organic light‐emitting diodes (OLEDs) that show monomer‐like emission spectra and high maximum external quantum efficiency (EQEmax) values of up to 3.1% for the doubly silicon‐bridged PBI. KW - organic light emitting diodes KW - perylene bisimide dyes KW - rigidification KW - solid‐state emission KW - vacuum processable Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-312599 VL - 11 IS - 5 ER - TY - JOUR A1 - Gryszel, Maciej A1 - Schlossarek, Tim A1 - Würthner, Frank A1 - Natali, Mirco A1 - Głowacki, Eric Daniel T1 - Water‐soluble cationic perylene diimide dyes as stable photocatalysts for H\(_2\)O\(_2\) evolution JF - ChemPhotoChem N2 - Photocatalytic generation of hydrogen peroxide, H\(_2\)O\(_2\), has gained increasing attention in recent years, with applications ranging from solar energy conversion to biophysical research. While semiconducting solid‐state materials are normally regarded as the workhorse for photogeneration of H\(_2\)O\(_2\), an intriguing alternative for on‐demand H\(_2\)O\(_2\) is the use of photocatalytic organic dyes. Herein we report the use of water‐soluble dyes based on perylene diimide molecules which behave as true molecular catalysts for the light‐induced conversion of dissolved oxygen to hydrogen peroxide. In particular, we address how to obtain visible‐light photocatalysts which are stable with respect to aggregation and photochemical degradation. We report on the factors affecting efficiency and stability, including variable electron donors, oxygen partial pressure, pH, and molecular catalyst structure. The result is a perylene diimide derivative with unprecedented peroxide evolution performance using a broad range of organic donor molecules and operating in a wide pH range. KW - hydrogen peroxide KW - oxygen reduction reaction KW - perylene KW - photocatalysis KW - dyes/pigments Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-370250 SN - 2367-0932 VL - 7 IS - 9 ER - TY - THES A1 - Neitz, Hermann T1 - Hydrophobic recognition motifs in functionalized DNA T1 - Hydrophobe Erkennungsmotive in funktionalisierter DNA N2 - In wässriger Umgebung spielen hydrophobe Wechselwirkungen eine wichtige Rolle für die DNA. Die Einführung von Modifikationen, die auf hydrophoben aromatischen Einheiten basieren, kann die Erkennung und Reaktivität von funktionellen Gruppen in der DNA steuern. Modifikationen können durch ein künstliches Rückgrat oder in Form einer Erweiterung der Nukleobasen eingebracht werden und so zu zusätzlichen Eigenschaften der DNA führen. Diese Dissertation befasst sich mit der Verwendung von hydrophoben Einheiten zur Funktionalisierung von DNA. Im ersten Teil der Arbeit wurde das Tolanmotiv (Diphenylacetylen) in Kombination mit dem acyclischen Rückgrat von GNA und BuNA verwendet, um Erkennungseinheiten im DNA-Kontext zu erzeugen. Die gezielte Fluorierung der aromatischen Ringe des Tolan-Bausteins bildete die Grundlage für eine supramolekulare Sprache, die auf Aren-Fluoroaren-Wechselwirkungen basiert. Die spezifische Erkennung wurde mittels thermodynamischer, kinetischer und NMR-spektroskopischer Methoden untersucht. Im zweiten Teil der Arbeit wurden Desoxyuridin-Derivate mit einer hydrophoben aromatischen Modifikation hergestellt und in die DNA-Doppelhelix eingebaut. Die Bestrahlung mit UV-Licht führte zu einer [2+2]-Cycloaddition zwischen zwei modifizierten Nukleosiden in der DNA. Das Reaktionsprodukt wurde strukturell charakterisiert und die Reaktion in verschiedenen biochemischen und nanotechnologischen DNA-Anwendungen eingesetzt. N2 - In aqueous environment, hydrophobic interactions play an important role for DNA. The introduction of modifications based on hydrophobic aromatic moieties offers additional ways for controlling recognition and reactivity of functional groups in DNA. Modifications are introduced through an artificial backbone or in the form of an extension of the nucleobases, resulting in additional properties of the DNA. This dissertation focuses on the use of hydrophobic units for the functionalization of DNA. In the first part of the work, the tolane (i. e. diphenylacetylene) motif was used in combination with the acyclic backbone of GNA and BuNA to generate recognition units in the DNA context. Fluorination of the aromatic rings in the tolane moiety provided the basis for a supramolecular language based on arene-fluoroarene interactions. The specific recognition was investigated by thermodynamic, kinetic and NMR spectroscopic methods. In the second part of the work, deoxyuridine derivatives with a hydrophobic aromatic modification were prepared and incorporated into DNA duplexes. The irradiation with UV light led to a [2+2] cycloaddition reaction between two modified nucleosides in the DNA. This reaction product was structurally characterized and the reaction was used in various biochemical and nanotechnological DNA applications. KW - Supramolekulare Chemie KW - Arene-Fluoroarene KW - Artificial Base Pair KW - Supramolecular Interaction KW - XNA KW - Crosslinking KW - DNA KW - DNS Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-348382 ER - TY - JOUR A1 - Noll, Niklas A1 - Würthner, Frank T1 - Bioinspired water preorganization in confined space for efficient water oxidation catalysis in metallosupramolecular ruthenium architectures JF - Accounts of Chemical Research N2 - Conspectus Nature has established a sustainable way to maintain aerobic life on earth by inventing one of the most sophisticated biological processes, namely, natural photosynthesis, which delivers us with organic matter and molecular oxygen derived from the two abundant resources sunlight and water. The thermodynamically demanding photosynthetic water splitting is catalyzed by the oxygen-evolving complex in photosystem II (OEC-PSII), which comprises a distorted tetramanganese–calcium cluster (CaMn\(_4\)O\(_5\)) as catalytic core. As an ubiquitous concept for fine-tuning and regulating the reactivity of the active site of metalloenzymes, the surrounding protein domain creates a sophisticated environment that promotes substrate preorganization through secondary, noncovalent interactions such as hydrogen bonding or electrostatic interactions. Based on the high-resolution X-ray structure of PSII, several water channels were identified near the active site, which are filled with extensive hydrogen-bonding networks of preorganized water molecules, connecting the OEC with the protein surface. As an integral part of the outer coordination sphere of natural metalloenzymes, these channels control the substrate and product delivery, carefully regulate the proton flow by promoting pivotal proton-coupled electron transfer processes, and simultaneously stabilize short-lived oxidized intermediates, thus highlighting the importance of an ordered water network for the remarkable efficiency of the natural OEC. Transferring this concept from nature to the engineering of artificial metal catalysts for fuel production has fostered the fascinating field of metallosupramolecular chemistry by generating defined cavities that conceptually mimic enzymatic pockets. However, the application of supramolecular approaches to generate artificial water oxidation catalysts remained scarce prior to our initial reports, since such molecular design strategies for efficient activation of substrate water molecules in confined nanoenvironments were lacking. In this Account, we describe our research efforts on combining the state-of-the art Ru(bda) catalytic framework with structurally programmed ditopic ligands to guide the water oxidation process in defined metallosupramolecular assemblies in spatial proximity. We will elucidate the governing factors that control the quality of hydrogen-bonding water networks in multinuclear cavities of varying sizes and geometries to obtain high-performance, state-of-the-art water oxidation catalysts. Pushing the boundaries of artificial catalyst design, embedding a single catalytic Ru center into a well-defined molecular pocket enabled sophisticated water preorganization in front of the active site through an encoded basic recognition site, resulting in high catalytic rates comparable to those of the natural counterpart OEC-PSII. To fully explore their potential for solar fuel devices, the suitability of our metallosupramolecular assemblies was demonstrated under (electro)chemical and photocatalytic water oxidation conditions. In addition, testing the limits of structural diversity allowed the fabrication of self-assembled linear coordination oligomers as novel photocatalytic materials and long-range ordered covalent organic framework (COF) materials as recyclable and long-term stable solid-state materials for future applications. KW - catalysts KW - catalytic activity KW - ligands KW - macrocycles KW - water oxidation KW - ruthenium Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-361232 SN - 0001-4842 VL - 57 IS - 10 ER - TY - JOUR A1 - Kirchner, Philipp H. A1 - Schramm, Louis A1 - Ivanova, Svetlana A1 - Shoyama, Kazutaka A1 - Würthner, Frank A1 - Beuerle, Florian T1 - A water-stable boronate ester cage JF - Journal of the American Chemical Society N2 - The reversible condensation of catechols and boronic acids to boronate esters is a paradigm reaction in dynamic covalent chemistry. However, facile backward hydrolysis is detrimental for stability and has so far prevented applications for boronate-based materials. Here, we introduce cubic boronate ester cages 6 derived from hexahydroxy tribenzotriquinacenes and phenylene diboronic acids with ortho-t-butyl substituents. Due to steric shielding, dynamic exchange at the Lewis acidic boron sites is feasible only under acid or base catalysis but fully prevented at neutral conditions. For the first time, boronate ester cages 6 tolerate substantial amounts of water or alcohols both in solution and solid state. The unprecedented applicability of these materials under ambient and aqueous conditions is showcased by efficient encapsulation and on-demand release of β-carotene dyes and heterogeneous water oxidation catalysis after the encapsulation of ruthenium catalysts. KW - absorption KW - hydrocarbons KW - materials KW - organic compounds KW - stability KW - boronate esters Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-361245 SN - 0002-7863 VL - 146 IS - 8 ER -