TY - JOUR A1 - He, Tao A1 - Stolte, Matthias A1 - Burschka, Christian A1 - Hansen, Nis Hauke A1 - Musiol, Thomas A1 - Kälblein, Daniel A1 - Pflaum, Jens A1 - Tao, Xutang A1 - Brill, Jochen A1 - Würthner, Frank T1 - Single-crystal field-effect transistors of new Cl\(_{2}\)-NDI polymorph processed by sublimation in air JF - Nature Communications N2 - Physical properties of active materials built up from small molecules are dictated by their molecular packing in the solid state. Here we demonstrate for the first time the growth of n-channel single-crystal field-effect transistors and organic thin-film transistors by sublimation of 2,6-dichloro-naphthalene diimide in air. Under these conditions, a new polymorph with two-dimensional brick-wall packing mode (\(\beta\)-phase) is obtained that is distinguished from the previously reported herringbone packing motif obtained from solution (\(\alpha\)-phase). We are able to fabricate single-crystal field-effect transistors with electron mobilities in air of up to 8.6 cm\(^{2}\)V\(^{-1}\)s\(^{-1}\) (\(\alpha\)-phase) and up to 3.5 cm\(^{2}\)V\(^{-1}\)s\(^{-1}\) (\(\beta\)-phase) on n-octadecyltriethoxysilane-modified substrates. On silicon dioxide, thin-film devices based on \(\beta\)-phase can be manufactured in air giving rise to electron mobilities of 0.37 cm\(^{2}\)V\(^{-1}\)s\(^{-1}\). The simple crystal and thin-film growth procedures by sublimation under ambient conditions avoid elaborate substrate modifications and costly vacuum equipment-based fabrication steps. KW - thin-film transistors KW - carrier transport KW - \(\beta\)-phase KW - organic semiconductors KW - induced phase transition KW - charge transport KW - materials design KW - \(\alpha\)-phase KW - mobility KW - pentacene Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-149255 VL - 6 IS - 5954 ER - TY - JOUR A1 - Hattori, Yohei A1 - Michail, Evripidis A1 - Schmiedel, Alexander A1 - Moos, Michael A1 - Holzapfel, Marco A1 - Krummenacher, Ivo A1 - Braunschweig, Holger A1 - Müller, Ulrich A1 - Pflaum, Jens A1 - Lambert, Christoph T1 - Luminescent Mono-, Di-, and Tri-radicals: Bridging Polychlorinated Triarylmethyl Radicals by Triarylamines and Triarylboranes JF - Chemistry - A European Journal N2 - Up to three polychlorinated pyridyldiphenylmethyl radicals bridged by a triphenylamine carrying electron withdrawing (CN), neutral (Me), or donating (OMe) groups were synthesized and analogous radicals bridged by tris(2,6‐dimethylphenyl)borane were prepared for comparison. All compounds were as stable as common closed‐shell organic compounds and showed significant fluorescence upon excitation. Electronic, magnetic, absorption, and emission properties were examined in detail, and experimental results were interpreted using DFT calculations. Oxidation potentials, absorption and emission energies could be tuned depending on the electron density of the bridges. The triphenylamine bridges mediated intramolecular weak antiferromagnetic interactions between the radical spins, and the energy difference between the high spin and low spin states was determined by temperature dependent ESR spectroscopy and DFT calculations. The fluorescent properties of all radicals were examined in detail and revealed no difference for high and low spin states which facilitates application of these dyes in two‐photon absorption spectroscopy and OLED devices. KW - density functional calculations KW - fluorescence KW - NIR OLED KW - radical KW - two-photon absorption Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-208162 VL - 25 IS - 68 ER - TY - JOUR A1 - Harkin, David J. A1 - Broch, Katharina A1 - Schreck, Maximilian A1 - Ceyman, Harald A1 - Stoy, Andreas A1 - Yong, Chaw-Keong A1 - Nikolka, Mark A1 - McCulloch, Ian A1 - Stingelin, Natalie A1 - Lambert, Christoph A1 - Sirringhaus, Henning T1 - Decoupling charge transport and electroluminescence in a high mobility polymer semiconductor JF - Advanced Materials N2 - Fluorescence enhancement of a high-mobility polymer semiconductor is achieved via energy transfer to a higher fluorescence quantum yield squaraine dye molecule on 50 ps timescales. In organic light-emitting diodes, an order of magnitude enhancement of the external quantum efficiency is observed without reduction in the charge-carrier mobility resulting in radiances of up to 5 W str\(^{-1}\) m\(^{-2}\) at 800 nm. KW - Light-emitting diodes KW - Fiels-effect transistors KW - Energy transfer KW - Conjugated polymers KW - High performance KW - High efficiency KW - Perovskite KW - Amplification KW - Fluorescence KW - Emission Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-187670 VL - 28 IS - 30 ER - TY - JOUR A1 - Götz, Ralph A1 - Kunz, Tobias C. A1 - Fink, Julian A1 - Solger, Franziska A1 - Schlegel, Jan A1 - Seibel, Jürgen A1 - Kozjak-Pavlovic, Vera A1 - Rudel, Thomas A1 - Sauer, Markus T1 - Nanoscale imaging of bacterial infections by sphingolipid expansion microscopy JF - Nature Communications N2 - Expansion microscopy (ExM) enables super-resolution imaging of proteins and nucleic acids on conventional microscopes. However, imaging of details of the organization of lipid bilayers by light microscopy remains challenging. We introduce an unnatural short-chain azide- and amino-modified sphingolipid ceramide, which upon incorporation into membranes can be labeled by click chemistry and linked into hydrogels, followed by 4x to 10x expansion. Confocal and structured illumination microscopy (SIM) enable imaging of sphingolipids and their interactions with proteins in the plasma membrane and membrane of intracellular organelles with a spatial resolution of 10-20nm. As our functionalized sphingolipids accumulate efficiently in pathogens, we use sphingolipid ExM to investigate bacterial infections of human HeLa229 cells by Neisseria gonorrhoeae, Chlamydia trachomatis and Simkania negevensis with a resolution so far only provided by electron microscopy. In particular, sphingolipid ExM allows us to visualize the inner and outer membrane of intracellular bacteria and determine their distance to 27.6 +/- 7.7nm. Imaging of lipid bilayers using light microscopy is challenging. Here the authors label cells using a short chain click-compatible ceramide to visualize mammalian and bacterial membranes with expansion microscopy. KW - nanoscale imaging KW - bacterial infection KW - sphingolipid expansion microscopy Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-231248 VL - 11 ER - TY - JOUR A1 - Görl, Daniel A1 - Zhang, Xin A1 - Stepanenko, Vladimir A1 - Würthner, Frank T1 - Supramolecular block copolymers by kinetically controlled co-self-assembly of planar and core-twisted perylene bisimides JF - Nature Communications N2 - New synthetic methodologies for the formation of block copolymers have revolutionized polymer science within the last two decades. However, the formation of supramolecular block copolymers composed of alternating sequences of larger block segments has not been realized yet. Here we show by transmission electron microscopy (TEM), 2D NMR and optical spectroscopy that two different perylene bisimide dyes bearing either a flat (A) or a twisted (B) core self-assemble in water into supramolecular block copolymers with an alternating sequence of (A\(_{m}\)BB)\(_{n}\). The highly defined ultralong nanowire structure of these supramolecular copolymers is entirely different from those formed upon self-assembly of the individual counterparts, that is, stiff nanorods (A) and irregular nanoworms (B), respectively. Our studies further reveal that the as-formed supramolecular block copolymer constitutes a kinetic self-assembly product that transforms into thermodynamically more stable self-sorted homopolymers upon heating. KW - cylindrical micelles KW - water KW - amplification KW - association KW - emission KW - organization KW - polymerization KW - dyes KW - fluorescent KW - aqueous medium Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-148657 VL - 6 IS - 7009 ER - TY - JOUR A1 - Görl, Daniel A1 - Soberats, Bartolome A1 - Herbst, Stefanie A1 - Stepanenko, Vladimir A1 - Würthner, Frank T1 - Perylene bisimide hydrogels and lyotropic liquid crystals with temperature-responsive color change JF - Chemical Science N2 - The self-assembly of perylene bisimide (PBI) dyes bearing oligo ethylene glycol (OEG) units in water affords responsive functional nanostructures characterized by their lower critical solution temperature (LCST). Tuning of the LCST is realized by a supramolecular approach that relies on two structurally closely related PBI–OEG molecules. The two PBIs socially co-assemble in water and the resulting nanostructures exhibit a single LCST in between the transition temperatures of the aggregates formed by single components. This permits to precisely tune the transition from a hydrogel to a lyotropic liquid crystal state at temperatures between 26 and 51 °C by adjusting the molar fraction of the two PBIs. Owing to concomitant changes in PBI–PBI interactions this phase transition affords a pronounced color change with “fluorescence-on” response that can be utilized as a smart temperature sensory system. KW - perylene bisimide hydrogels Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-162459 VL - 7 IS - 11 ER - TY - THES A1 - Gsänger, Marcel T1 - Organic Thin-Film Transistors Based on Dipolar Squaraine Dyes T1 - Organische Dünnschichttransistoren von dipolaren Squarainfarbstoffen N2 - In summary, it can be stated that the herein studied set of acceptor-substituted squaraine dyes can be seen as potent candidates for OTFTs. Furthermore, their transistor performance can be easily tuned to obtain hole mobilities up to 0.45 cm2/Vs from solution and 1.3 cm2/Vs from sublimation by choosing adequate deposition techniques. In the end, a probable structural model derived from studies of the thin-film morphology by methods such as optical spectroscopy, AFM and X-ray even facilitated the clarification of the observed charge transport behavior. N2 - Zusammenfassend lässt sich sagen, dass die in dieser Arbeit untersuchten akzeptorsubstituierten Squarainfarbstoffe durchaus als leistungsfähige Kandidaten für den Einsatz in OTFT-Bauteilen angesehen werden können. Ihre Transistorleistung lässt sich durch geeignete Wahl der Abscheidungsmethode dahingehend einstellen, als dass sich Lochmobilitäten von bis zu 0.45 cm2/Vs mittels Lösungsprozessierung und von bis zu 1.3 cm2/Vs mittels Sublimation realisieren lassen. Schließlich ermöglichte die Untersuchung der Dünnfilmmorphologie mit Methoden wie der optischen Spektroskopie, Rasterkraftmikroskopie und Röntgenbeugung die Schlussfolgerung auf ein mutmaßliches Strukturmodell. KW - Organische Chemie KW - Squaraine KW - Organischer Feldeffekttransistor KW - Organic Chemistry KW - Squaraine KW - Organic Field-Effect Transistor KW - Organischer Halbleiter Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-80588 ER - TY - THES A1 - Grüne, Marvin T1 - Solid-state NMR Spectroscopic, X-Ray Diffraction and Quantum Chemical Investigations of the Crystalline Cancer Drug Paclitaxel and Paclitaxel incorporated into Polymer Micelles T1 - Festkörper-NMR-, Röntgendiffraktometrie- und quantenchemische Untersuchungen des kristallinen Krebs-Wirkstoffs Paclitaxel und Paclitaxel eingebettet in Polymermizellen N2 - Paclitaxel (PTX) is one of the leading drugs against breast and ovarian cancer. Due to its low solubility, treatment of the patients with this drug requires a very well-suited combination with a soluble pharmaceutical excipient to increase the bioavailability and reduce the strong side ef-fects. One efficient way to achieve this in the future could be the incorporation of PTX into pol-ymeric micelles composed of poly(2-oxazoline) based triblock copolymers (POL) which ena-bles PTX loadings of up to 50 wt.%. However, structural information at an atomic level and thus the knowledge of interaction sites within these promising but complex PTX-POL formula-tions were not yet available. Such results could support the future development of improved excipients for PTX and suitable excipients for other pharmaceutical drugs. Therefore, a solid-state MAS NMR investigation of these amorphous formulations with different POL-PTX com-positions was performed in this thesis as this gives insights of the local structure at an atomic level in its solid state. NMR in solution showed very broad 13C signals of PTX for this system due to the reduced mobility of the incorporated drug which exclude this as an analytical meth-od. In a first study, crystalline PTX was structurally characterized by solid-state NMR as no com-plete 13C spectrum assignment and no 1H NMR data existed for the solid state. In addition, the asymmetric unit of the PTX crystal structure consists of two molecules (Z'=2) that can only be investigated in its solid state. As crystalline PTX in total has about 100 different 13C and 1H chemical shifts with very small differences due to Z’=2, and furthermore, its unit cell consisting of more than 900 atoms, accompanying GIPAW (CASTEP) calculations were required for NMR signal assignments. These calculations were performed using the first three available purely hydrous and anhydrous PTX structures, which were determined by XRD and published by Vel-la-Zarb et al. in 2013. Within this thesis, is was discovered that two investigated batches of commercially available PTX from the same supplier both contained an identical and so far un-known PTX phase that was elucidated by PXRD as well as solid-state NMR data. One of the two batches consists of an additional phase that was shown to be very similar to a known hy-drated phase published in 2013.[1] By heating the batch with the mixture of the two phases un-der vacuum, it is transformed completely to the new dry phase occurring in both PTX batches. Since the drying conditions to obtain anhydrous PTX in-situ on the PXRD setup described by Vella-Zarb et. al.[1] were much softer than ours, we identify our dry phase as a relaxed version of their published anhydrate structure. The PXRD data of the new anhydrate phase was trans-ferred into a new structural model, which currently undergoes geometry optimization. Based on solid-state NMR data at MAS spinning frequencies up to 100 kHz, a 13C and a partial 1H signal assignment for the new anhydrous structure were achieved. These results provided sufficient structural information for further investigations of the micellar POL-PTX system. In a second study, the applicability and benefit of two-dimensional solid-state 14N-1H HMQC MAS NMR spectra for the characterization of amorphous POL-PTX formulations was investi-gated. The mentioned technique has never been applied to a system of similar complexity be-fore and was chosen because around 84% of the small-molecule drugs contain at least one nitrogen atom. In addition, the number of nitrogen atoms in both POL and PTX is much smaller than the number of carbons or hydrogens, which significantly reduces the spectral complexity. 14N has a natural abundance of 99.6% but leads to quadrupolar broadening due to its nuclear spin quantum number I = 1. While this is usually undesirable due to broadening in the resulting 1D 14N NMR spectra, this effect is explicitly used in the 2D 14N-1H HMQC MAS experiment. The indirect 14N measurement can avoid the broadening while maintaining the advantage of the high natural abundance and making use of the much more dispersed signals due to the additional quadrupolar shifts as compared to 15N. This measurement method could be successfully applied to the complex amorphous POL-PTX mixtures. With increasing PTX loading of the formulations, additional peaks arise as spatial proximities of the amide nitrogens of POL to NH or OH groups of PTX. In addition, the 14N quadrupolar shift of these amide nitrogens decreases with increasing PTX content indicating a more symmetric nitrogen environment. The latter can be explained by a transformation of the trigonal planar coordination of the tertiary amide nitrogen atoms in pure POL towards a more tetrahedral environment upon PTX loading induced by the formation of hydrogen bonds with NH/OH groups of PTX. In the third and last project, the results of the two abovementioned studies were used and ex-tended by solid state 13C and two-dimensional 1H-13C as well as 1H-1H MAS NMR data with the aim to derive a structural model of the POL-PTX formulations at an atomic level. The knowledge of the NMR signal assignments for crystalline PTX was transferred to amorphous PTX (present in the micelles of the formulations). The 13C solid-state NMR signals were evalu-ated concerning changes in chemical shifts and full widths of half maximum (FWHM) for the different PTX loadings. In this way, the required information about possible interaction sites at an atomic level becomes available. Due to the complexity of these systems, such proximities often cannot be assigned to special atoms, but more to groups of atoms, as the individual de-velopments of line widths and line shifts are mutually dependent. An advantageous aspect for this analysis was that pure POL already forms unloaded micelles. The evaluation of the data showed that the terminal phenyl groups of PTX seem to be most involved in the interaction by the establishment of the micelle for lowest drug loading and that they are likely to react to the change in the amount of PTX molecules as well. For the incorporation of PTX in the micelles, the following model could be obtained: For lowest drug loading, PTX is mainly located in the inner part of the micelles. Upon further increasing of the loading, it progressively extends to-ward the micellar shell. This could be well shown by the increasing interactions of the hydro-phobic butyl chain of POL and PTX, proceeding in the direction of the polymer backbone with rising drug load. Furthermore, due to the size of PTX and the hydrodynamic radius of the mi-celles, even at the lowest loading, the PTX molecules partially reach the core-shell interface of the micelle. Upon increasing the drug loading, the surface coverage with PTX clusters increas-es based on the obtained model approach. The latter result is supported by DLS and SANS data of this system. The abovementioned results of the 14N-1H HMQC MAS investigation of the POL-PTX formulations support the outlined model. As an outlook, the currently running geometry optimization and subsequently scheduled calcu-lation of the chemical shieldings of the newly obtained anhydrous PTX crystal structure can further improve the solid-state NMR characterization through determination of further spatial proximities among protons using the existing 2D 1H(DQ)-1H(SQ) solid-state MAS NMR spec-trum at 100 kHz rotor spinning frequency. The 2D 14N-1H HMQC MAS NMR experiments were shown to have great potential as a technique for the analysis of other disordered and amor-phous drug delivery systems as well. The results of this thesis should be subsequently applied to other micellar systems with varying pharmaceutical excipients or active ingredients with the goal of systematically achieving higher drug loadings (e.g., for the investigated PTX, the similar drug docetaxel or even different natural products). Additionally, it is planned to transfer the knowledge to another complex polymer system containing poly(amino acids) which offers hy-drogen bonding donor sites for additional intermolecular interactions. Currently, the POL-PTX system is investigated by further SANS studies that may provide another puzzle piece to the model as complementary measurement method in the future. In addition, the use of MD simu-lations might be considered in the future. This would allow a computerized linking of the differ-ent pieces of information with the aim to determine the most likely model. N2 - Paclitaxel (PTX) ist eines der führenden Medikamente gegen Brust-und Eierstockkrebs. Aufgrund seiner geringen Löslichkeit erfordert die Behandlung der Patienten mit diesem Medikament eine sehr gut geeignete Kombination mit einem löslichen pharmazeutischenHilfsstoff, um die Bioverfügbarkeit zu erhöhen und die starken Nebenwirkungen zu reduzieren. Ein effizienter Weg, dies in Zukunft zu erreichen, könnte der Einbau von PTX in polymere Mizellen sein, die aus Poly(2-oxazolin)-basierten Triblock-Copolymeren (POL) bestehen und PTX-Beladungen von bis zu 50 Gew.-% ermöglichen. Strukturelle Informationen auf atomarer Ebene und damit die Kenntnis von Wechselwirkungeninnerhalb dieser vielversprechenden, aber komplexen PTX-POL-Formulierungen waren jedoch bisher nichtverfügbar. Solche Ergebnisse könnten die zukünftige Entwicklung von verbesserten Hilfsstoffen für PTX und von geeigneten Hilfsstoffen für andere pharmazeutische Wirkstoffe unterstützen. Aus diesem Grund wurdenin der vorliegenden DissertationFestkörper-NMR-Untersuchungen andiesenamorphen Formulierungen mit unterschiedlichen POL-PTX Zusammensetzungen durchgeführt, weil damit Einblickein die lokale Struktur auf atomarer Ebene im festen Zustand erhalten werden können. Aufgrund der verringerten Mobilität des eingebrachten Wirkstoffs in diesem System ergeben NMR-Messungen in Lösung sehr breite 13C-PTX-Signale, was diese Technikals Analysemethode ausschließt. ... KW - Wirkstoff-Träger-System KW - NMR-Spektroskopie KW - Röntgendiffraktometrie KW - Taxol KW - Quantenchemie KW - Solid-State NMR Spectroscopy KW - X-Ray Diffraction KW - Quantum Chemical Calculations KW - Drug Delivery System KW - Taxol KW - Festkörper-NMR KW - quantenchemische Berechnungen Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-237199 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 - JOUR A1 - Griesbeck, Stefanie A1 - Michail, Evripidis A1 - Rauch, Florian A1 - Ogasawara, Hiroaki A1 - Wang, Chenguang A1 - Sato, Yoshikatsu A1 - Edkins, Robert M. A1 - Zhang, Zuolun A1 - Taki, Masayasu A1 - Lambert, Christoph A1 - Yamaguchi, Shigehiro A1 - Marder, Todd B. T1 - The Effect of Branching on the One‐ and Two‐Photon Absorption, Cell Viability, and Localization of Cationic Triarylborane Chromophores with Dipolar versus Octupolar Charge Distributions for Cellular Imaging JF - Chemistry – A European Journal N2 - Two different chromophores, namely a dipolar and an octupolar system, were prepared and their linear and nonlinear optical properties as well as their bioimaging capabilities were compared. Both contain triphenylamine as the donor and a triarylborane as the acceptor, the latter modified with cationic trimethylammonio groups to provide solubility in aqueous media. The octupolar system exhibits a much higher two‐photon brightness, and also better cell viability and enhanced selectivity for lysosomes compared with the dipolar chromophore. Furthermore, both dyes were applied in two‐photon excited fluorescence (TPEF) live‐cell imaging. KW - boranes KW - cell imaging KW - fluorescence KW - lysosome KW - two-photon excited fluorescence Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-212887 VL - 25 IS - 57 SP - 13164 EP - 13175 ER -