@article{AbdelhameedEltamanyHaletal.2020,
  author    = {Abdelhameed, Reda F. A. and Eltamany, Enas E. and Hal, Dina M. and Ibrahim, Amany K. and AboulMagd, Asmaa M. and Al-Warhi, Tarfah and Youssif, Khayrya A. and Abd El-kader, Adel M. and Hassanean, Hashim A. and Fayez, Shaimaa and Bringmann, Gerhard and Ahmed, Safwat A. and Abdelmohsen, Usama Ramadan},
  title     = {New cytotoxic cerebrosides from the Red Sea cucumber Holothuria spinifera supported by in-silico studies},
  series = {Marine Drugs},
  volume    = {18},
  journal   = {Marine Drugs},
  number    = {8},
  issn      = {1660-3397},
  doi       = {10.3390/md18080405},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-211089},
  year      = {2020},
  abstract  = {Bioactivity-guided fractionation of a methanolic extract of the Red Sea cucumber Holothuria spinifera and LC-HRESIMS-assisted dereplication resulted in the isolation of four compounds, three new cerebrosides, spiniferosides A (1), B (2), and C (3), and cholesterol sulfate (4). The chemical structures of the isolated compounds were established on the basis of their 1D NMR and HRMS spectral data. Metabolic profiling of the H. spinifera extract indicated the presence of diverse secondary metabolites, mostly hydroxy fatty acids, diterpenes, triterpenes, and cerebrosides. The isolated compounds were tested for their in vitro cytotoxicities against the breast adenocarcinoma MCF-7 cell line. Compounds 1, 2, 3, and 4 displayed promising cytotoxic activities against MCF-7 cells, with IC\(_{50}\) values of 13.83, 8.13, 8.27, and 35.56 µM, respectively, compared to that of the standard drug doxorubicin (IC\(_{50}\) 8.64 µM). Additionally, docking studies were performed for compounds 1, 2, 3, and 4 to elucidate their binding interactions with the active site of the SET protein, an inhibitor of protein phosphatase 2A (PP2A), which could explain their cytotoxic activity. This study highlights the important role of these metabolites in the defense mechanism of the sea cucumber against fouling organisms and the potential uses of these active molecules in the design of new anticancer agents.},
  language  = {en}
}
@article{AbdelhameedHabibEltahawyetal.2020,
  author    = {Abdelhameed, Reda F. A. and Habib, Eman S. and Eltahawy, Nermeen A. and Hassanean, Hashim A. and Ibrahim, Amany K. and Mohammed, Anber F. and Fayez, Shaimaa and Hayallah, Alaa M. and Yamada, Koji and Behery, Fathy A. and Al-Sanea, Mohammad M. and Alzarea, Sami I. and Bringmann, Gerhard and Ahmed, Safwat A. and Abdelmohsen, Usama Ramadan},
  title     = {New cytotoxic natural products from the Red Sea sponge Stylissa carteri},
  series = {Marine Drugs},
  volume    = {18},
  journal   = {Marine Drugs},
  number    = {5},
  issn      = {1660-3397},
  doi       = {10.3390/md18050241},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-205795},
  year      = {2020},
  abstract  = {Bioactivity-guided isolation supported by LC-HRESIMS metabolic profiling led to the isolation of two new compounds, a ceramide, stylissamide A (1), and a cerebroside, stylissoside A (2), from the methanol extract of the Red Sea sponge Stylissa carteri. Structure elucidation was achieved using spectroscopic techniques, including 1D and 2D NMR and HRMS. The bioactive extract's metabolomic profiling showed the existence of various secondary metabolites, mainly oleanane-type saponins, phenolic diterpenes, and lupane triterpenes. The in vitro cytotoxic activity of the isolated compounds was tested against two human cancer cell lines, MCF-7 and HepG2. Both compounds, 1 and 2, displayed strong cytotoxicity against the MCF-7 cell line, with IC\(_{50}\) values at 21.1 ± 0.17 µM and 27.5 ± 0.18 µM, respectively. They likewise showed a promising activity against HepG2 with IC\(_{50}\) at 36.8 ± 0.16 µM for 1 and IC\(_{50}\) 30.5 ± 0.23 µM for 2 compared to the standard drug cisplatin. Molecular docking experiments showed that 1 and 2 displayed high affinity to the SET protein and to inhibitor 2 of protein phosphatase 2A (I2PP2A), which could be a possible mechanism for their cytotoxic activity. This paper spreads light on the role of these metabolites in holding fouling organisms away from the outer surface of the sponge, and the potential use of these defensive molecules in the production of novel anticancer agents.},
  language  = {en}
}
@article{AbdelhameedHabibGodaetal.2020,
  author    = {Abdelhameed, Reda F. A. and Habib, Eman S. and Goda, Marwa S. and Fahim, John Refaat and Hassanean, Hashem A. and Eltamany, Enas E. and Ibrahim, Amany K. and AboulMagd, Asmaa M. and Fayez, Shaimaa and Abd El-kader, Adel M. and Al-Warhi, Tarfah and Bringmann, Gerhard and Ahmed, Safwat A. and Abdelmohsen, Usama Ramadan},
  title     = {Thalassosterol, a New Cytotoxic Aromatase Inhibitor Ergosterol Derivative from the Red Sea Seagrass Thalassodendron ciliatum},
  series = {Marine Drugs},
  volume    = {18},
  journal   = {Marine Drugs},
  number    = {7},
  doi       = {10.3390/md18070354},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-236085},
  year      = {2020},
  abstract  = {Thalassodendron ciliatum (Forssk.) Den Hartog is a seagrass belonging to the plant family Cymodoceaceae with ubiquitous phytoconstituents and important pharmacological potential, including antioxidant, antiviral, and cytotoxic activities. In this work, a new ergosterol derivative named thalassosterol (1) was isolated from the methanolic extract of T. ciliatum growing in the Red Sea, along with two known first-reported sterols, namely ergosterol (2) and stigmasterol (3), using different chromatographic techniques. The structure of the new compound was established based on 1D and 2D NMR spectroscopy and high-resolution mass spectrometry (HR-MS) and by comparison with the literature data. The new ergosterol derivative showed significant in vitro antiproliferative potential against the human cervical cancer cell line (HeLa) and human breast cancer (MCF-7) cell lines, with IC\(_{50}\) values of 8.12 and 14.24 µM, respectively. In addition, docking studies on the new sterol 1 explained the possible binding interactions with an aromatase enzyme; this inhibition is beneficial in both cervical and breast cancer therapy. A metabolic analysis of the crude extract of T. ciliatum using liquid chromatography combined with high-resolution electrospray ionization mass spectrometry (LC-ESI-HR-MS) revealed the presence of an array of phenolic compounds, sterols and ceramides, as well as di- and triglycerides.},
  language  = {en}
}
@phdthesis{Abdelmohsen2010,
  author    = {Abdelmohsen, Usama Ramadan},
  title     = {Antimicrobial Activities from Plant Cell Cultures and Marine Sponge-Associated Actinomycetes},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-51483},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2010},
  abstract  = {This thesis is divided into three parts with the main goal allocating novel antimicrobial compounds that could be used as future antibiotics. The first part aimed to evaluate the potential of plant suspension cultures for the production of antimicrobial proteins. The extracellular, intracellular and cell wall bound fractions of seven heterotrophic and photomixotrophic plant cell suspension cultures treated with nine different elicitors were tested for the elicitor dependent production of antimicrobial proteins. Bioactivities were tested against a selected panel of human isolates including Gram-positive and Gram-negative bacteria as well as fungi using the disc diffusion assay. The intracellular fractions of elicited cell cultures were more active than extracellular fractions while the cell wall bound fractions showed lowest activities. Among the 21 fractions tested, the intracellular fraction of Lavendula angustifolia elicited with DC3000 was most active against Candida maltosa. The second most active fraction was the intracellular fraction of Arabidopsis thaliana elicited with salicylic acid which was moreover active against all test strains. The antimicrobial activity of elicited Arabidopsis thaliana cell cultures was tested by bioautography to locate the antimicrobial proteins in the crude extract. The intracellular fraction of photomixotrophic Arabidopsis thaliana cells elicited with salicylic acid was selected for further gel filtration chromatography on S-200 column leading to the purification of one 19 kDa antimicrobially active protein, designated, AtAMP. Our findings suggest that elicited plant cell cultures may present a new promising alternative source of antimicrobial proteins. The second part comprises the isolation of actinomycetes associated with marine sponges and testing the bioactivities of new species for further investigations. Actinobacterial communities of eleven taxonomically different sponges that had been collected from offshore Ras Mohamed (Egypt) and from Rovinj (Croatia) were investigated by a culture-based approach using different standard media for isolation of actinomycetes and media enriched with aqueous sponge extract to target rare and new actinomycete species. Phylogenetic characterization of 52 representative isolates out of 90 based on almost complete sequences of genes encoding 16S rRNA supported their assignment to 18 different actinomycete genera. Altogether 14 putatively new species were identified based on sequence similarity values below 98.2\% to other strains in the NCBI database. The use of M1 agar amended with aqueous sponge extract yielded a putative new genus related to Rubrobacter which highlighting the need for innovative cultivation protocols. Biological activity testing showed that five isolates were active against Gram-positives only, one isolate was active against Candida albicans only and one isolate showed activity against both groups of pathogens. Moreover, the antiparasistic activity was documented for four isolates. These results showed a high diversity of actinomycetes associated with marine sponges as well as highlighted their potential to produce anti-infective agents. The third part of the thesis focused on the isolation and structure elucidation of new bioactive compounds. Streptomyces strain RV15 recovered from sponge Dysidea tupha, was selected for further chemical analysis by virtue of the fact that it exhibited the greatest antimicrobial potential against Staphylococcus aureus as well as Candida albicans among the all tested strains. Moreover, members of the genus Streptomyces are well known as prolific producers of interesting pharmacologically active metabolites. Chemical analysis of the methanolic crude extract using different chromatographic tools yielded four new compounds. The structures of the new compounds were spectroscopically elucidated to be four new cyclic peptides, namely, cyclodysidins A-D. Their bioactivity was tested against different proteases, bacteria and Candida as well as tumor cell lines. The compounds did not show any significant activities at this point.},
  subject      = {Antimikrobieller Wirkstoff},
  language  = {en}
}
@phdthesis{Ackermann2023,
  author    = {Ackermann, Johannes},
  title     = {Entwicklung verbesserter Verfahren zur Herstellung, Modifizierung und Charakterisierung diamantbasierter Materialien},
  doi       = {10.25972/OPUS-27360},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-273608},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2023},
  abstract  = {In dieser Dissertation wird beschrieben, wie es durch systematische Anwendung unterschiedlicher Methoden zur Herstellung und Modifizierung von Diamant gezielt und verl{\"a}sslich m{\"o}glich ist, die Eigenschaften von Diamanten zu beeinflussen. Es wird gezeigt, wie durch Variation der Parameter bei dem Wachstum von Diamant Einfluss auf dessen Morphologie und Eigenschaften genommen werden kann. Des Weiteren wird ein Verfahren vorgestellt, mit dem die Oberfl{\"a}che des Diamanten durch Ozon effizient oxidiert beziehungsweise reduziert werden kann. Um diese ver{\"a}nderte Oberfl{\"a}chenbelegung m{\"o}glichst genau zu analysieren, wird im letzten Teil der Dissertation eine Methode zur qualitativen und quantitativen Analytik der Oberfl{\"a}chen von Kohlenstoffnanomaterialien beschrieben.},
  subject      = {Diamant},
  language  = {de}
}
@phdthesis{Albert2012,
  author    = {Albert, Christian Robert},
  title     = {N,C-verkn{\"u}pfte Arylisochinoline: Synthese und Optimierung der biologischen Aktivit{\"a}ten sowie Strukturaufkl{\"a}rung von Naturstoffen durch HPLC-NMR- und HPLC-MS/MS-Kopplung},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-76537},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2012},
  abstract  = {Tropische Infektionskrankheiten wie Malaria, Leishmaniose oder auch die Afrikanische Trypanosomiase sind aufgrund von zunehmenden Resistenzen der Erreger, globaler Erw{\"a}rmung, aber auch von Vers{\"a}umnissen in der Vergangenheit bei der kontinuierlichen Weiterentwicklung bestehender sowie der Erforschung neuer Medikamente auch im 21. Jahrhundert noch eine große Bedrohung f{\"u}r Millionen von Menschen. Die Suche nach neuartigen Wirkstoffen und deren Weiterentwicklung zu potenziellen Medikamenten ist daher zwingend erforderlich. Insbesondere Produkte des Sekund{\"a}rstoffwechsels wie etwa die Alkaloide bilden wichtige Grundlagen als Leitstrukturen f{\"u}r pharmazeutische Wirkstoffe. Eine solche Klasse phytochemischen Ursprungs sind die Naphthylisochinolin-Alkaloide mit interessanten strukturellen Eigenschaften sowie pharmakologischen Wirksamkeiten. Einige Vertreter zeigen ausgepr{\"a}gte In-vitro-Aktivit{\"a}ten gegen protozoische Erreger wie Plasmodien, Leishmanien und Trypanosomen. Besonders die neuartige Unterklasse ionischer N,C-verkn{\"u}pfter Naphthylisochinolin-Alkaloide, wie z.B. Ancistrocladinium A und Ancistrocladinium B, zeichnen sich durch gute antileishmaniale Wirkungen aus. In Vorarbeiten zeigten erste Studien zu Struktur-Aktivit{\"a}ts-Beziehungen (SAR-Studien) mit vereinfachten N,C-gekuppelten Arylisochinolinen, dass sich durch gezielte Strukturvariation die Aktivit{\"a}t gegen einen Erreger verbessern l{\"a}sst. Zus{\"a}tzlich wurde mit ersten Untersuchungen zum Wirkmechanismus dieser interessanten Verbindungen begonnen. Dar{\"u}ber hinaus erm{\"o}glicht die kontinuierliche Verbesserung der analytischen Methoden inzwischen die schnelle und gezielte Suche nach neuen Verbindungen aus der Natur. Durch die Anwendung von Online-Analyse-Verfahren, wie z.B. die Kopplung von HPLC mit NMR und MS, gelingt die Aufkl{\"a}rung der Konstitution von Substanzen direkt aus Extrakten. Ziel der vorliegenden Arbeit war die Verbesserung der biologischen Aktivit{\"a}ten der N,C-verkn{\"u}pften Arylisochinoline durch strukturelle Derivatisierung sowie Beitr{\"a}ge zur Aufkl{\"a}rung des Wirkmechanismus mittels markierter Verbindungen. Zus{\"a}tzlich sollten Naturstoffe unter Verwendung moderner HPLC-Kopplungstechniken untersucht und strukturell aufgekl{\"a}rt werden.},
  subject      = {HPLC},
  language  = {de}
}
@article{AltmannMutWolfetal.2021,
  author    = {Altmann, Stephan and Mut, J{\"u}rgen and Wolf, Natalia and Meißner-Weigl, Jutta and Rudert, Maximilian and Jakob, Franz and Gutmann, Marcus and L{\"u}hmann, Tessa and Seibel, J{\"u}rgen and Ebert, Regina},
  title     = {Metabolic glycoengineering in hMSC-TERT as a model for skeletal precursors by using modified azide/alkyne monosaccharides},
  series = {International Journal of Molecular Sciences},
  volume    = {22},
  journal   = {International Journal of Molecular Sciences},
  number    = {6},
  issn      = {1422-0067},
  doi       = {10.3390/ijms22062820},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-259247},
  year      = {2021},
  abstract  = {Metabolic glycoengineering enables a directed modification of cell surfaces by introducing target molecules to surface proteins displaying new features. Biochemical pathways involving glycans differ in dependence on the cell type; therefore, this technique should be tailored for the best results. We characterized metabolic glycoengineering in telomerase-immortalized human mesenchymal stromal cells (hMSC-TERT) as a model for primary hMSC, to investigate its applicability in TERT-modified cell lines. The metabolic incorporation of N-azidoacetylmannosamine (Ac\(_4\)ManNAz) and N-alkyneacetylmannosamine (Ac\(_4\)ManNAl) into the glycocalyx as a first step in the glycoengineering process revealed no adverse effects on cell viability or gene expression, and the in vitro multipotency (osteogenic and adipogenic differentiation potential) was maintained under these adapted culture conditions. In the second step, glycoengineered cells were modified with fluorescent dyes using Cu-mediated click chemistry. In these analyses, the two mannose derivatives showed superior incorporation efficiencies compared to glucose and galactose isomers. In time-dependent experiments, the incorporation of Ac\(_4\)ManNAz was detectable for up to six days while Ac\(_4\)ManNAl-derived metabolites were absent after two days. Taken together, these findings demonstrate the successful metabolic glycoengineering of immortalized hMSC resulting in transient cell surface modifications, and thus present a useful model to address different scientific questions regarding glycosylation processes in skeletal precursors.},
  language  = {en}
}
@phdthesis{Amslinger2012,
  author    = {Amslinger, Barbara},
  title     = {Isolierung, Totalsynthese, Stereostruktur und -dynamik neuartiger mono- und dimerer Naphthylisochinoline},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-76156},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2012},
  abstract  = {Nach wie vor ist die Zahl der Malaria-Neuerkrankungen mit ca. 500 Millionen Menschen weltweit sehr besorgniserregend. Durch zunehmende Resistenzen der Erreger gegen zahlreiche Arzneimittel wird die Situation zus{\"a}tzlich versch{\"a}rft. Daher ist die Suche und Entwicklung neuartiger Medikamente wichtiger denn je. Die Natur ist immer noch das gr{\"o}ßte Reservoir an neuen Wirkstoffen, welche als Leitstrukturen f{\"u}r Arzneistoffe fungieren. In den letzten Jahren wurde eine große Zahl neuartiger, biologisch aktiver Naturstoffe identifiziert und hinsichtlich ihres Potenzials f{\"u}r eine pharmazeutische Weiterentwicklung analysiert. Die Naphthylisochinolin-Alkaloide geh{\"o}ren zu solch einer vielversprechenden Wirkstoffklasse, da sie sich v.a. durch ihre hervorragenden pharmakologischen Eigenschaften auszeichnen. K{\"u}rzlich wurden die ersten N,C-gekuppelten Naphthyldihydroisochinolin-Alkaloide, Ancistrocladinium A und B, entdeckt. Diese Verbindungen weisen als strukturelle Besonderheit eine außergew{\"o}hnliche Iminium-Aryl-Achse auf und besitzen zudem exzellente anti-infektive Aktivit{\"a}ten, insbesondere gegen den Erreger der Orientbeule, Leishmania major. Ziel der vorliegenden Dissertation war die Synthese neuartiger sterisch gehinderter und strukturell vereinfachter Naphthylisochinoline f{\"u}r weiterf{\"u}hrende Struktur-Aktivit{\"a}ts-Beziehungen (SAR-Studien) und die stereochemische Analyse dieser Verbindungen. Zudem sollte eine Syntheseroute zu den neuartigen dimeren C,C-gekuppelten Naphthylisochinolin-Alkaloiden Shuangancistrotectorin A und B entwickelt werden.},
  subject      = {Totalsynthese},
  language  = {de}
}
@phdthesis{Amthor2005,
  author    = {Amthor, Stephan},
  title     = {Redox properties of Bis-Triarylamines and ligand properties of Thianthrenophane},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-15916},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2005},
  abstract  = {The one electron oxidation potential of ten TAAs with all permutations of Cl , OMe- and Me-substituents in the three p-positions were determined by CV. The half wave potential of the first oxidation wave correlates linearly with the number of Cl- and OMe-substituents. AM1-CISD derived values of the absorption energies are in good agreement with the experiments but differ strongly for the oscillator strengths as well as for neutral compounds and their corresponding mono radical cations. The small solvent dependence of the experimental UV/Vis spectra in CH2Cl2 and MeCN reflects a minor charge transfer character of the electronic transitions. The UV/Vis/NIR spectra of the series of TAAs and their corresponding radical cations and the AM1 computations reveal that even small substituents may lead to strong symmetry breaking and to a modified electronic structure. The spectroscopic properties of a series of four bis-TAA donor-bridge-donor X-B-X dimers, composed of two asymmetric TAA chromophores (monomers) were investigated. UV/vis-, fluorescence and transient absorption spectra were recorded and compared with those of the corresponding X-B monomers. The excited states of the dimers are described as MV states which show, depending on the chemical nature of the bridge, a varying amount of interactions. It was found that superradiant emission only proceeds in the case of weak and medium coupling. Whether the first excited state potential energy surface of the dimers is a single minimum or a double minimum potential depends on the solvent polarity and the electronic coupling. In the latter case, the dimer relaxes in a symmetry broken CT state. The [2.2]paracyclophane bridged dimer is an example for a weakly coupled system, because the spectroscopic behavior is very similar to the corresponding p xylene monomer. In contrast, anthracene as well as p-xylene bridges mediate a stronger coupling and reveal a significant cooperative influence on the optical properties. A series of [2.2]paracylophane bridged bis-TAA MV radical cations X-B-X+ were analyzed by a GMH three-level model which takes two transitions into account: the IV-CT band and the bridge band. From the GMH analysis, one can conclude that the [2.2]paracyclophane moiety is not the limiting factor which governs the intramolecular charge transfer. The electronic interactions are of course smaller than direct conjugation but from the order of magnitude of the couplings of the [2.2]paracyclophane MV species it can be assumed that this bridge is able to mediate significant through-space and through-bond interactions. From the exponential dependence of the electronic coupling V between the two TAA localized states on the distance r between the two redox centers, it was inferred that the HT proceeds via superexchange mechanism. The analysis reveals that even significantly longer conjugated bridges should still mediate significant electronic interactions, because the decay constant of a series of conjugated MV species is small. The absorption properties of a series of bis-TAA-[2.2]paracyclophane dications X+-B-X+ were presented. The localized and the CT transitions of these dications are explained and analyzed by an exciton coupling model which also considers the photophysical properties of the monomeric TAA radical cations. Together with AM1-CISD calculated transition moments, experimental transition moments and transition energies of the bis-TAA dications were used to calculate electronic couplings by a GMH approach. These couplings are a measure for interactions of the excited MV CT states. The modification of the diabatic states reveals similarities of the GMH three-level model and the exciton coupling model. Comparison of the two models shows that the transition moment between the excited mixed-valence states of the dimer equals the dipole moment difference of the ground and the excited bridge state of the corresponding monomer. Thianthrenophane (1) has a cavity which offers enough room to potentially enable endohedral coordination to small ions or molecules. For the complexation of silver(I) perchlorate, the complex stability constants of thianthrenophane logK1=5.45 and of thianthrene logK2=9.16 were determined by UV/Vis titration. Single competition transport experiments with ten metal salts demonstrate a very high selectivity of thianthrenophane as a carrier for silver(I) and a distinctly higher transport rate compared to carriers such as thianthrene and 14-ane-S4. Although the X-ray crystal structure analysis of the polymeric [Ag(1)]ClO4 shows an exohedral coordination to silver(I), the formation of an endohedral [Ag(1)]+ complex is suggested to be the explanation for the unusual carrier selectivity of silver(I) by 1 in bulk liquid membrane.},
  subject      = {Triarylamine},
  language  = {en}
}
@phdthesis{ArjonaEsteban2015,
  author    = {Arjona Esteban, Alhama},
  title     = {Merocyanine Dyes as Organic Semiconductors for Vacuum-processed Solar Cell and Transistor Devices},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-129096},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2015},
  abstract  = {The present thesis comprises the synthesis of new functional merocyanine dyes, the study of their electro-optical properties as well as solid state packing and their application as p-type semiconductor materials in transistor and solar cell devices. The absorption properties of the obtained compounds could be modified by variation of the donor unit, the introduction of electron-withdrawing substituents in the acceptor unit or elongation of the polymethine chain. For a particular dye, the absorption band could be shifted by more than 160 nm by increasing the solvent polarity due to a conformational switch between a merocyanine-like and a cyanine-like structure. Single crystal analyses revealed that the studied dyes tend to pack either in an antiparallel fashion forming dimers with no overall dipole moment or in a staircase-like pattern where the dipole moments point to the same direction and are only balanced by another staircase oriented in the opposite direction (stair dimer). With respect to application as semiconductor materials, the latter packing arrangement resulted most favorable for charge carrier mobility. We concluded that this packing motif is preserved in the solar cell devices, where the selenium-containing dye afforded the highest performance of this series for an optimized planar-mixed heterojunction solar cell (6.2 \%).},
  subject      = {Merocyanine},
  language  = {en}
}