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 - Shen, Chia-An A1 - Bialas, David A1 - Hecht, Markus A1 - Stepanenko, Vladimir A1 - Sugiyasu, Kazunori A1 - Würthner, Frank T1 - Polymorphism in squaraine dye aggregates by self-assembly pathway differentiation: panchromatic tubular dye nanorods versus J-aggregate nanosheets JF - Angewandte Chemie International Edition N2 - A bis(squaraine) dye equipped with alkyl and oligoethyleneglycol chains was synthesized by connecting two dicyanomethylene substituted squaraine dyes with a phenylene spacer unit. The aggregation behavior of this bis(squaraine) was investigated in non-polar toluene/tetrachloroethane (98:2) solvent mixture, which revealed competing cooperative self-assembly pathways into two supramolecular polymorphs with entirely different packing structures and UV/Vis/NIR absorption properties. The self-assembly pathway can be controlled by the cooling rate from a heated solution of the monomers. For both polymorphs, quasi-equilibrium conditions between monomers and the respective aggregates can be established to derive thermodynamic parameters and insights into the self-assembly mechanisms. AFM measurements revealed a nanosheet structure with a height of 2 nm for the thermodynamically more stable polymorph and a tubular nanorod structure with a helical pitch of 13 nm and a diameter of 5 nm for the kinetically favored polymorph. Together with wide angle X-ray scattering measurements, packing models were derived: the thermodynamic polymorph consists of brick-work type nanosheets that exhibit red-shifted absorption bands as typical for J-aggregates, while the nanorod polymorph consists of eight supramolecular polymer strands of the bis(squaraine) intertwined to form a chimney-type tubular structure. The absorption of this aggregate covers a large spectral range from 550 to 875 nm, which cannot be rationalized by the conventional exciton theory. By applying the Essential States Model and considering intermolecular charge transfer, the aggregate spectrum was adequately reproduced, revealing that the broad absorption spectrum is due to pronounced donor-acceptor overlap within the bis(squaraine) nanorods. The latter is also responsible for the pronounced bathochromic shift observed for the nanosheet structure as a result of the slip-stacked arranged squaraine chromophores. KW - organic chemistry KW - supramolecular polymers KW - nanorods and nanosheets KW - polymorphism KW - squaraine dyes KW - cooperative self-assembly Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-256443 IS - 21 ET - 60 ER - TY - JOUR A1 - Denner, Ansgar A1 - Dittmaier, Stefan A1 - Hecht, Markus A1 - Pasold, Christian T1 - NLO QCD and electroweak corrections to Z + γ production with leptonic Z-boson decays JF - JOURNAL OF HIGH ENERGY PHYSICS N2 - The next-to-leading-order electroweak corrections to pp→l\(^{+}\)l\(^{-}\)/ν¯¯¯ν+γ+X production, including all off-shell effects of intermediate Z bosons in the complex-mass scheme, are calculated for LHC energies, revealing the typically expected large corrections of tens of percent in the TeV range. Contributions from quark-photon and photon-photon initial states are taken into account as well, but their impact is found to be moderate or small. Moreover, the known next-to-leading-order QCD corrections are reproduced. In order to separate hard photons from jets, both a quark-to-photon fragmentation function á la Glover/Morgan and Frixione’s cone isolation are employed. The calculation is available in the form of Monte Carlo programs allowing for the evaluation of arbitrary differential cross sections. Predictions for integrated cross sections are presented for the LHC at 7 TeV, 8 TeV, and 14 TeV, and differential distributions are discussed at 14 TeV for bare muons and dressed leptons. Finally, we consider the impact of anomalous ZZγ and Zγγ couplings. KW - NLO computations KW - hadronic colliders KW - LHC Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-168766 VL - 02 IS - 057 ER - TY - THES A1 - Hecht, Markus T1 - Liquid-Crystalline Perylene Bisimide and Diketopyrrolopyrrole Assemblies T1 - Flüssigkristalline Perylenbisimid- und Diketopyrrolopyrrolstrukturen N2 - The research presented in this thesis illustrates that self-assembly of organic molecules guided by intermolecular forces is a versatile bottom-up approach towards functional materials. Through the specific design of the monomers, supramolecular architectures with distinct spatial arrangement of the individual building blocks can be realized. Particularly intriguing materials can be achieved when applying the supramolecular approach to molecules forming liquid-crystalline phases as these arrange in ordered, yet mobile structures. Therefore, they exhibit anisotropic properties on a macroscopic level. It is pivotal to precisely control the interchromophoric arrangement as functions originate in the complex structures that are formed upon self-assembly. Consequently, the aim of this thesis was the synthesis and characterization of liquid-crystalline phases with defined supramolecular arrangements as well as the investigation of the structure-property relationship. For this purpose, perylene bisimide and diketopyrrolopyrrole chromophores were used as they constitute ideal building blocks towards functional supramolecular materials due to their thermal stability, lightfastness, as well as excellent optical and electronic features desirable for the application in, e.g., organic electronics. N2 - Mithilfe von Gestaltungsprinzipien der supramolekularen Chemie können komplexe Strukturen realisiert werden, die mit Ansätzen der kovalenten Chemie nicht erreichbar sind. Ein zentraler Aspekt ist hierbei der systematische Aufbau der Monomereinheiten, welche unter geeigneten Bedingungen über intermolekulare Wechselwirkungen selbstassemblieren und Architekturen mit spezifischer räumlicher Anordnung der einzelnen Bauelemente formen. Flüssigkristalline Materialien zeigen zusätzlich zu positioneller und Orientierungsfernordnung der Moleküle, welche anisotrope Eigenschaften auf makroskopischer Ebene erzeugen, eine gewisse Mobilität. Daher können durch Kombination des supramolekularen Ansatzes mit Flüssigkristallen besonders interessante Materialien erzeugt werden. Da die spezische Anordnung der Moleküle die Funktion des selbstassemblierten Materials stark beeinflusst, ist es von großer Bedeutung, diese exakt kontrollieren zu können. Daher war es Ziel dieser Arbeit, flüssigkristalline Phasen mit einer definierten supramolekularen Struktur zu synthetisieren und zu charakterisieren. Weiterhin war es ein Ziel, diese auf ihre funktionellen Eigenschaften zu untersuchen, die aus der spezifischen Anordnung der Monomereinheiten hervorgehen. Für diesen Zweck wurden Perylenbisimid- und Diketopyrrolopyrrolfarbstoffe als Baueinheiten verwendet, da diese aufgrund ihrer Licht- und Hitzestabilität sowie exzellenten optischen und elektronischen Eigenschaften ideale Materialien für die Anwendung in der organischen Elektronik darstellen. KW - Selbstorganisation KW - Flüssigkristall KW - Perylenderivate KW - Perylene Bisimide KW - Liquid Crystal KW - J-Aggregates KW - Photoconductivity KW - Self-Assembly KW - Perylenbisimid Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-216987 ER - TY - JOUR A1 - Hecht, Markus A1 - Erber, Sonja A1 - Harrer, Thomas A1 - Klinker, Hartwig A1 - Roth, Thomas A1 - Parsch, Hans A1 - Fiebig, Nora A1 - Fietkau, Rainer A1 - Distel, Luitpold V. T1 - Efavirenz Has the Highest Anti-Proliferative Effect of Non-Nucleoside Reverse Transcriptase Inhibitors against Pancreatic Cancer Cells JF - PLoS ONE N2 - Background Cancer prevention and therapy in HIV-1-infected patients will play an important role in future. The non-nucleoside reverse transcriptase inhibitors (NNRTI) Efavirenz and Nevirapine are cytotoxic against cancer cells in vitro. As other NNRTIs have not been studied so far, all clinically used NNRTIs were tested and the in vitro toxic concentrations were compared to drug levels in patients to predict possible anti-cancer effects in vivo. Methods Cytotoxicity was studied by Annexin-V-APC/7AAD staining and flow cytometry in the pancreatic cancer cell lines BxPC-3 and Panc-1 and confirmed by colony formation assays. The 50% effective cytotoxic concentrations (EC50) were calculated and compared to the blood levels in our patients and published data. Results The in vitro EC50 of the different drugs in the BxPC-3 pancreatic cancer cells were: Efavirenz 31.5\(\mu\)mol/l (= 9944ng/ml), Nevirapine 239\(\mu\)mol/l (= 63786ng/ml), Etravirine 89.0\(\mu\)mol/l (= 38740ng/ml), Lersivirine 543\(\mu\)mol/l (= 168523ng/ml), Delavirdine 171\(\mu\)mol/l (= 78072ng/ml), Rilpivirine 24.4\(\mu\)mol/l (= 8941ng/ml). As Efavirenz and Rilpivirine had the highest cytotoxic potential and Nevirapine is frequently used in HIV-1 positive patients, the results of these three drugs were further studied in Panc-1 pancreatic cancer cells and confirmed with colony formation assays. 205 patient blood levels of Efavirenz, 127 of Rilpivirine and 31 of Nevirapine were analyzed. The mean blood level of Efavirenz was 3587ng/ml (range 162-15363ng/ml), of Rilpivirine 144ng/ml (range 0-572ng/ml) and of Nevirapine 4955ng/ml (range 1856-8697ng/ml). Blood levels from our patients and from published data had comparable Efavirenz levels to the in vitro toxic EC50 in about 1 to 5% of all patients. Conclusion All studied NNRTIs were toxic against cancer cells. A low percentage of patients taking Efavirenz reached in vitro cytotoxic blood levels. It can be speculated that in HIV-1 positive patients having high Efavirenz blood levels pancreatic cancer incidence might be reduced. Efavirenz might be a new option in the treatment of cancer. KW - human hepatic cells KW - active antiretroviral therapy KW - differentiated thyroid tumor KW - HIV-infected patients KW - pharmacokinetic interaction KW - LINE-1 retrotransposition KW - HIV-1-infected subjects KW - healthy volunteers KW - prostate cancer KW - i-131 uptake Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-151694 VL - 10 IS - 6 ER -