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Bowl-shaped naphthalimide-annulated corannulene as nonfullerene acceptor in organic solar cells
(2020)
An electron-poor bowl-shaped naphthalimide-annulated corannulene with branched alkyl residues in the imide position was synthesized by a palladium-catalyzed cross-coupling annulation sequence. This dipolar compound exhibits strong absorption in the visible range along with a low-lying LUMO level at –3.85 eV, enabling n-type charge transport in organic thin-film transistors. Furthermore, we processed inverted bulk-heterojunction solar cells in combination with the two donor polymers PCE–10 and PM6 to achieve open-circuit voltages up to 1.04 V. By using a blend of the self-assembled naphthalimide-annulated corannulene and PCE–10, we were able to obtain a power conversion efficiency of up to 2.1%, which is to the best of our knowledge the highest reported value for a corannulene-based organic solar cell to date.
no abstract available
Optimal open-loop control, i.e. the application of an analytically derived control rule, is demonstrated for nanooptical excitations using polarization-shaped laser pulses. Optimal spatial near-field localization in gold nanoprisms and excitation switching is realized by applying a shift to the relative phase of the two polarization components. The achieved near-field switching confirms theoretical predictions, proves the applicability of predefined control rules in nanooptical light–matter interaction and reveals local mode interference to be an important control mechanism.
Background: Melatonin (MLT) has many health implications, therefore it is of valuable importance to develop specific analytical methods for determination of MLT in the presence of its main contaminant, N-{2-[1-({3-[2-(acetylamino)ethyl]-5-methoxy-1H-indol-2-yl}methyl)-5-methoxy-1H-indol-3-yl]ethyl}acetamide (10). For development of these analytical methods, compound 10 had to be prepared in an adequate amount. Results: Compound 10 was synthesized in six steps starting from 5-methoxyindole-2-carboxylic acid (1). Analytical performance of the proposed spectrofluorimetric methods was statistically validated with respect to linearity, accuracy, precision and specificity. The proposed methods were successfully applied for the assay of MLT in laboratory prepared mixtures containing up to 60 % of compound 10 and in commercial MLT tablets with recoveries not less than 99.00 %. No interference was observed from common pharmaceutical additives and the results were favorably compared with those obtained by a reference method. Conclusions: This work describes simple, sensitive, and reliable second derivative spectrofluorimetric method in addition to two multivariate calibration methods, principal component regression (PCR) and partial least square (PLS), for the determination of MLT in the presence of compound 10.
Background It is well known that carbohydrates play fundamental roles in cell signaling and infection processes as well as tumor formation and progression. However, the interaction pathways and cellular receptors targeted by carbohydrates and glycoconjugates remain poorly examined and understood. This lack of research stems, at least to a major part, from accessibility problems of large, branched oligosaccharides. Results To test glycan - cell interactions in vitro, a variety of tailored oligosaccharides was synthesized chemo-enzymatically. Glycosyltransferases from the GRAS organisms Bacillus megaterium (SacB) and Aspergillus niger (Suc1) were used in this study. Substrate engineering of these glycosyltransferases generally acting on sucrose leads to the controlled formation of novel tailored di-, tri- and tetrasaccharides. Already industrially used as prebiotics in functional food, the immunogenic potential of novel oligosaccharides was characterized in this study. A differential secretion of CXCL8 and CCL2 was observed upon oligosaccharide co-cultivation with colorectal epithelial Caco-2 cells. Conclusion Pure carbohydrates are able to stimulate a cytokine response in human endothelial cells in vitro. The type and amount of cytokine secretion depends on the type of co-cultivated oligosaccharide.
no abstract available
The He (I) photoelectron spectra of 2-bicyclo[2.1.l]hexene (1), 2,3-bis(methylene)bicyclo[2.1.l]hexane (3), and 3,4-bis(methylene)tricyclo[3.l.O.0\(^{2.6}\)]hexane (4) have been investigated. The assignment given is based on a ZDO model and semiempirical calculations. Tagether with the PE data of benzvalene (2), the reported data allow a comparison between 1-2 and 3-4. This yields a measure of the interactions between 8 cyclobutane or 8 bicyclobutane moiety and a double bond system within a ZDO model. The resonance integral found in the case of 1 and 3 amounts to -1.9 eV, that for 2 and 4, to -2.3 eV. The investigations furthermore reveal that the electronic factors which contribute to the higher reactivity of the bicyclobutane compounds amount to 5 kcal/mol.
In den Reaktionen von Tetracyanethylen (TCNE) und 5,6-Dichlor-2,3-dicyan-p-benzochinon mit Benzvalen haben wir kürzlich die ersten Beispiele für die lange gesuchte einstufige 1,4-Cycloaddition eines Alkens an ein Vinylcyclopropan gcfunden(I~J. Sie ist als [(.,2.+.2s)+ 112J-Prozeß der Dicls-Alder-Addition nahe verwandtllbl. Allerdings entsteht das betreffende TCNE-Addukt, ein Dihydrosemibullvalen-Derivat, nur in einer Ausbeute von wenigen Prozent. Die Hauptprodukte gehen aus einer Zwitterionischen Zwischenstufe hervor, die durch Anlagerung von TCNE an die Benzvalen-n-Bindung resultiert.
Professor Rolf Huisgen zum 65. Geburtstag gewidmet