Ein einfaches Sensorfeld aus einem anionischen und einem kationischen Poly(para-phenylenethinylen) (PPE) sowie deren elektrostatischem Komplex unterscheidet verschiedene Weißweine. Die PPEs und der Komplex wurden bei pH 13 verwendet. Der Komplex wurde auch bei pH 3 eingesetzt. Diese aus vier Sensorelementen bestehende “chemische Zunge”, unterscheidet 13 verschiedene Weißweine. Grundlage der sensorischen Erkennung ist die Fluoreszenzlöschung der konjugierten Polymere. Die Fluoreszenzlöschung wird nicht durch die Hauptkomponenten des Weines induziert, denn Säuren, Zucker, Alkohole usw. zeigen keine Fluoreszenzlöschung. Die vorrangigen Löscher sind vielmehr die im Wein befindlichen farbigen Tannine und andere Polyphenole. Die Löschung der PPE-Fluoreszenz durch die Tannine wird allerdings von den Hauptkomponenten des Weines moduliert.

Thermal condensation of 2,3-diamino-1,4-(bistriisopropylsilylethynyl)benzene, -naphthalene,-anthracene, and -benzothiadiazole substrates with 1,2-naphthalenedione forms bent benzophenazine-type heteroarenes in a one-step reaction in good to excellent yields. The targets are investigated by UV/Vis spectroscopy, cyclic voltammetry, and single-crystal X-ray crystallography. The packing of the targets in the solid state follows either a herringbone or a brick wall motif. In the case of 8,13-bis(triisopropylsilylethynyl)dibenzo[a,i]phenazine, polymorphs with either packing result.

One fluorescent, positively charged poly(para-phenyleneethynylene) (PAE 1) forms electrostatic complexes with five negatively charged pyridine- or benzothiadiazole-containing poly(para-aryleneethynylene)s (PAE 2–PAE 6). The PAE 2–PAE 6 are less fluorescent in water and act as quenchers for PAE 1 in their electrostatic complexes C 1–C 5; the PAE-complexes (2 μm) were exposed to thirteen different carboxylic acids (50 mm) in buffered aqueous solution. The fluorescence responses of the small library of electrostatic PAE–complexes towards the acids was analyzed; discrimination of all of the thirteen acids was achieved. The investigated acids include acetic, butyric, tartaric, maleic, lactic, sorbic, oxalic, aspartic, and citric acids. A random, simple, ad-hoc library of electrostatic polymer complexes, C 1–C 5, therefore discerns the thirteen carboxylic acids in water.

Novel synthetic methodologies allow increasingly efficient access to known organic materials, as well as the preparation of otherwise inaccessible species. Pd-catalyzed coupling of aromatic dihalides to ortho-diaminoarenes furnishes embedded stable N,N′-dihydropyrazines expediently and in often excellent yields. The embedded N,N′-dihydropyrazines can then be oxidized by MnO₂ to give substituted azatetracenes, azapentacenes, azahexacenes, and azaheptacenes, which are soluble, processable, and stable. This powerful Pd-catalyzed methodology allows the preparation of azaacenes, including diaza-, tetraaza- and hexaazaacenes. In combination with a suitable Pd precursor, Buchwald-type biarylphosphines have been shown to give excellent results. Activated dihalides such as 2,3-dihaloquinoxalines are coupled easily under simplified conditions, whereas 2,3-dibromoacenes require more stringent conditions and advanced catalyst precursors. Pd catalysts effect the assembly of azaacenes with otherwise difficult to obtain substitution patterns. High yields and flexibility make this method most attractive.

The synthesis of 2,3,5,6-tetrakis(2,6-difluorophenyl)di(styryl)benzene by using a conventional synthetic sequence, including Diels–Alder and Horner reactions is reported. The target is an effective aggregation-induced emitter. It is photostable with respect to electrocyclization, due to the presence of the fluorine substituents. This compound undergoes photochemical trans/cis isomerization of its styryl double bonds.

We present a simple array composed of an anionic and a cationic poly(para-phenyleneethynylene) (PPE), together with an electrostatic complex between the two of them. The individual PPEs and the PPE complex were employed in the sensing of white wines at pH 13; the complex was also successfully employed as a sensor element at pH 3. The sensing mechanism is fluorescence quenching. Thirteen different wines were differentiated by this chemical tongue, which consists of four elements. The fluorescence quenching is not induced by the major components of the wines. Compounds such as acids, sugars, and alcohols alone do not quench the fluorescence, but rather the colored tannins and other polyphenols contained in wine are the main quenchers. However, the major constituents of wine significantly modulate the quenching of the PPEs by the tannins.

The synthesis of five novel distyrylbenzene (DSB) derivatives, featuring a central tetraphenylbenzene core, is reported. The targets show aggregation-induced emission (AIE), which, however, is substituent-dependent. For the pure hydrocarbon and derivatives that do not carry (+M) or (−M) substituents, classic AIE behavior is observed, that is, the DSBs are non-fluorescent in solution, but are highly fluorescent in cold matrices, upon aggregate formation in poor solvents and in the solid, crystalline state. If aldehyde or dibutylamino groups are attached in the para-position of the DSB unit, non-classic AIE-phores result. These are fluorescent both in dilute solution as well as in the solid state. Prolonged irradiation of the targets leads to benzotetraphene derivatives by a double cyclization.

Die Prozessierung organischer Bauelemente aus der Flüssigphase ist ein wichtiger Schritt zur Entwicklung kostengünstiger Fertigungsprozesse. Wir beschreiben eine Methode zur lichtinduzierten Löslichkeitsschaltung eines π-konjugierten Polymers (Polyfluoren), dessen Seitenketten mit Hydroxyzimtsäureester funktionalisiert sind. Die Belichtung dünner Polymerfilme führt zur Abspaltung der Seitenketten, wodurch die Löslichkeit der Filme drastisch gesenkt wird. In einer ersten Konzeptstudie wurden die synthetisierten Polyfluorene als Emittermaterialien in OLEDs eingesetzt. Belichtung der Emitterschicht führt außer der Löslichkeitsschaltung auch zu einem deutlichen Leistungsanstieg der OLED. Dieser Befund eröffnet die Möglichkeit zur gezielten Manipulation der Löslichkeit und der Emissionseigenschaften einer wichtigen Klasse funktioneller Materialien.

Zwei konjugierte, mikroporöse Polymere (CMPs) auf Basis von Tetrakis(4-ethinylphenyl)stannan als formaler Wiederholungseinheit wurden synthetisiert und hinsichtlich ihrer BET-Oberflächen sowie ihrer thermischen Eigenschaften untersucht. Wir beschreiben zum ersten Mal eine direkte Methode zur Evaluierung der Molekülstruktur der organischen Verstrebungen, welche die Zinnzentren in den CMPs miteinander verbinden. Die gezielte und milde Zersetzung der Zinn-CMPs erfolgt durch die Einwirkung von Chloressigsäure, wobei die Zinn-Kohlenstoff-Bindungen gespalten und die überraschend diversen Strukturen der organischen Brücken gezielt evaluiert werden können.

Liquid-phase processing is a key prerequisite for the cost-efficient fabrication of organic electronic devices. We report an approach for light-induced modulation of the solubility of π-conjugated polymers (polyfluorene) with side chains functionalized with hydroxycinnamic acid. Irradiation with light cleaves the solubilizing side chains and renders the thin films of the polyfluorene insoluble. In a proof of concept device, polyfluorenes were applied as emissive layers in OLEDs. Photoirradiation of the emission layer leads to an increase in OLED performance combined with a modulation of the solubility of the thin film. These results offer the possibility for further development in terms of manipulating the solubility and emissive parameters of an important class of functional materials.

Two different conjugated microporous polymers (CMPs) based on tetrakis(4-ethynylphenyl)stannane as the repeating unit were synthesized and their BET surfaces and thermal properties were investigated. The first direct method to elucidate the molecular structure of the organic linkers between the tin centers by digestion of the CMP is described. Selective cleavage of the tin–carbon bonds with chloroacetic acid afforded the isolated bridging units and provided insight into the surprisingly varied chemical composition of these networks.

We describe the efficient synthesis of substituted benzo[3,4]cyclobuta[1,2-b]phenazine, benzo[3,4]cyclobuta[1,2]benzo[1,2-i]phenazine, and benzo[3,4]cyclobuta[1,2-b]naphtho[2,3-i]phenazine by a condensation reaction of aromatic diamines with the stable biphenylene-2,3-dione.

The palladium-catalyzed coupling of a substituted o-diaminoanthracene and a substituted o-diaminophenazine to substituted 2,3-dichloroquinoxalines furnishes 10 differently substituted N,N′-dihydrotetraaza- or -hexaazahexacenes with the quinoxaline group of the azaacenes carrying fluorine, chlorine, or nitro groups. The N,N′-dihydrotetraazahexacenes with hydrogen, chlorine, and fluorine subtituents are oxidized to azaacenes, whereas only the parent N,N′-dihydrohexaazahexacenes, with hydrogen substituents, are oxidized by MnO₂. The resultant azaacenes are characterized by their optical and spectroscopic data. In addition, single-crystal X-ray structures have been obtained for the parent tetraazahexacenes and their difluoro-substituted derivatives. The di- and tetrachloro derivatives of the N,N′-dihydrohexaazahexacene have also been structurally characterized.

Combining the molecular wire effect with a biphasic sensing approach (analyte in water, sensor-dye in 2-methyltetrahydrofuran) and a microfluidic flow setup leads to the construction of a mercury-sensitive module. We so instantaneously detect Hg²⁺ ions in water at a 500 μM concentration. The sensor, conjugated non-water soluble polymer 1 (XFPF), merely supports dibutylaniline substituents as binding units. Yet, selective and sensitive detection of Hg²⁺-ions is achieved in water. The enhancement in sensory response, when comparing the reference compound 2 to that of 1 in a biphasic system in a microfluidic chip is >10³. By manipulation of the structure of 1, further powerful sensor systems should be easily achieved.

A series of ethynylated silanes, including tetraethynylsilane, was treated with tetraphenylcyclopentadienone at 300 °C under microwave irradiation to give the aromatized Diels–Alder adducts as sterically encumbered mini-dendrimers with up to 20 benzene rings. The sterically most congested adducts display red-shifted emission through intramolecular π–π interactions in the excited state.

The antimicrobial potency of phenazine derivatives is attenuated by their inherently hydrophobic nature, complicating their use as antibiotic drugs. We have analyzed the cytotoxicity and mode of action of water-soluble bis-triazolyl phenazines against E. coli and a human epithelial (HaCat) cell line. We observed complete inhibition of bacterial growth over concentration ranges that do not affect the viability of human epithelial cells. Confocal fluorescence microscopy revealed a high degree of interaction between the phenazine compounds and E. coli, as well as evidence of membrane damage in phenazine-treated E. coli. Additional data suggests that the potency of these particular water-soluble phenazine compounds does not result from the production of reactive oxygen species, but rather from cytotoxic interference with metabolic electron-transfer cascades.

The known tetrakis((trimethylsilyl)ethynyl)silane was prepared and deprotected. By using trifluoromethanesulfonic acid, the smooth stepwise desilylation of the starting material was achieved, and all of the partially protected and the fully deprotected species were isolated by sublimation. Crystal structures of all of the partially and the fully deprotected species were obtained. None of the compounds is thermally sensitive. Attempts to explosively decompose these species upon heating failed.

Two literature-known TIPS-ethynyl-dibromoacenes were prepared and employed to synthesize cyclotrimers by using Yamamoto coupling conditions. Two large, well-soluble starphenes were isolated in good yields. Crystallographic characterization verifies the triangular shape and shows significant differences in crystal packing.

Azaacene sind seit langem bekannt, entweder als N,N′-Dihydroverbindungen oder in ihrer oxidierten Form als 4 n+2π-Systeme, aber erst seit kurzer Zeit versucht man, prozessierbare und charakterisierbare Derivate zu erhalten. In den letzten drei Jahren wurden neue Synthesewege für größere N-Heteroacene entwickelt. Besonders die Pd-katalysierten Kupplungen aromatischer Diamine mit aktivierten aromatischen Dihalogeniden haben zahlreiche neuartige Azaacene einfach zugänglich gemacht. Seit 2010 konnte eine Vielzahl Azapentacene und stabiler Oligoazahexacene synthetisiert werden, darunter auch ein symmetrisches Tetraazapentacen, das ein ausgezeichnetes Elektronentransportmaterial für Dünnschichttransistoren darstellt.

The photophysical properties of a series of para-substituted donor–acceptor cruciform fluorophores (p1–4) were investigated and compared with their meta and ortho isomers (m1–4 and o1–4). The structural variations were found to have a significant effect on the solvatochromism, fluorescence quantum yields (Φ_fl), fluorescence lifetimes (τ_fl), and response upon addition of trifluoroacetic acid. The observed spectral shifts in absorption and emission caused by protonation of the cruciforms make them promising candidates as chemosensors. Additional computational studies provided more insight into the electronic structure of the systems.

Azaacenes have been known for a very long time, either as N,N′-dihydro compounds or in their oxidized form as 4 n+2π systems, but only recently have processable and charcterizable derivatives been sought. In the last three years synthetic routes to large N-heteroacenes have been developed. In particular, the Pd-catalyzed coupling of aromatic diamines with activated aromatic dihalogenides has enabled simple access to numerous new azaacenes. Since 2010, azapentacene and stabile oligoazahexacene have been synthesized, as well as a symmetrical tetraazapentacene, which acts as an excellent electron-transport material for thin-film transistors.

Alkene metathesis is a superb methodology. We report the progress using alkene metathesis in the synthesis of polymeric organic semiconductors. Three classes of polymers have been synthesized using acyclic diene metathesis (ADMET) or ring opening metathesis polymerization (ROMP), viz., poly(acetylene)s (PA), poly(arylene-vinylene)s (PAV), and organometallic polymers. For PAs, ROMP of cyclooctatetraenes is best, whereas for PAV, both ADMET and indirect and direct ROMP are viable. Metathesis performs flawlessly with the correct monomers, as molybdenum and particularly the robust Ru carbenes demonstrate. When performing ROMP, one is often rewarded with structurally uniform polymers that can display very low polydispersities. Overall, metathesis is a powerful tool for the preparation of semiconducting polymers.

Dialkynylated BODIPYs bearing pyridine or dibutylaniline substituents have been synthesized, and their photophyisical properties in the presence of different metal ions have been studied. 4-Pyridyl substitution gives a highly selective fluorescence probe for Hg^II ions.

A series of functionalized diaza- and tetraazatetracenes was synthesized, either by condensation of an aromatic diamine with an ortho-quinone/diethyloxalate followed by chlorination with POCl₃ to give diazatetracenes or by palladium-catalyzed coupling of a phenylenediamine with various 2,3-dichloroquinoxalines to give tetraazatetracenes (after oxidation with MnO₂). Representative examples included halogenated and nitrated derivatives. The optical properties of these azatetracenes were discussed with respect to their molecular structures and substitution patterns. The diazatetracenes and tetraazatetracenes formed two different groups that had significantly different electronic structures and properties. Furthermore, 1,2,3,4-tetrafluoro-6,11-bis((triisopropylsilyl)ethynyl)benzo[b]phenazine was synthesized, which is the first reported fluorinated diazatetracene. Single-crystal X-ray analysis of this compound is reported.

We demonstrate that aldehyde-substituted donor–acceptor cruciforms [1,4-bis(arylethynyl)-2,5-distyrylbenzenes] are useful dosimeters for primary amines, primary diamines, and secondary amines. The 1,n-diamines are particularly reactive towards this dosimeter and can be detected in less than 100 ppm concentration. Using a single aldehyde-functionalized cruciform in seven different solvents allowed us to discern fourteen different amines by digital photography and statistical evaluation of the response patterns extracted as red, green, blue (RGB) values.

Two amphoteric cruciforms 6 and 7 (XF; 4,4′-[(1E,1′E)-(2,5-bis{[4-(dibutylamino)phenyl]ethynyl}-1,4-phenylene)bis(ethene-2,1-diyl)]diphenol, 4,4′-[{2,5-bis[(E)-4-(dibutylamino)styryl]-1,4-phenylene}bis(ethyne-2,1-diyl)]diphenol) were prepared by a Horner reaction followed by a Sonogashira coupling and subsequent deprotection. The XFs display significant changes in absorption and emission when exposed to trifluoroacetic acid, tetrabutylammonium hydroxide, and metal triflates. The substitution pattern of 6 and 7 leads to spatial separation of the frontier molecular orbitals, which allows the HOMO or LUMO of the XF to be addressed independently by acidic or basic agents. XF 6, which has hydroxyl groups on the styryl axis, displays changes in emission color upon exposure to ten amines in eight different solvents. The change in fluorescence upon the addition of amines was analyzed by linear discriminant analysis. These XFs may have potential in sensor applications for metal cations and amines.