Solvent free hydrostannation and Stille reactions using ionic liquid supported organotin reagents

Hydrostannation reactions were performed cleanly using ionic liquid supported organotin reagents. These green reducing agents were used both under free radical and palladium-catalyzed conditions. One of the new ionic liquid supported organotin reagents so obtained was evaluated successfully in Stille cross-coupling reactions to give aryl-substituted allylic alcohols in solvent free conditions

Functional DNA-grafted supramolecular polymers-chirality, cargo binding and hierarchical organization

\u3cp\u3eThe synthesis, characterization and functionalization of DNA-grafted supramolecular polymers are described. Cargo loading of the helical supramolecular assemblies with gold nanoparticles is demonstrated.\u3c/p\u3

Morphological diversity of supramolecular polymers of DNA-containing oligopyrenes-formation of chiroptically active nanosheets

\u3cp\u3eThe effect of DNA on the morphology of supramolecular polymers assembled from chimeric DNA-pyrene oligophosphodiesters in water is described. The number of deoxynucleotides determines if the self-assembly yields 1D or 2D structures. A single guanosine nucleotide attached to a heptapyrenotide induces chiroptical activity in self-assembled nanosheets.\u3c/p\u3

Morphological diversity of supramolecular polymers of DNA-containing oligopyrenes-formation of chiroptically active nanosheets

The effect of DNA on the morphology of supramolecular polymers assembled from chimeric DNA-pyrene oligophosphodiesters in water is described. The number of deoxynucleotides determines if the self-assembly yields 1D or 2D structures. A single guanosine nucleotide attached to a heptapyrenotide induces chiroptical activity in self-assembled nanosheets

Assembling Multiporphyrin Stacks Inside the DNA Double Helix

Double stranded DNA hybrids containing up to four consecutive, face-to-face stacked porphyrins are described. Non-nucleosidic, 5,15-bisphenyl-substituted porphyrin building blocks were incorporated into complementary oligonucleotide strands. Upon hybridization multiple porphyrins are well accommodated inside the DNA scaffold without disturbing the overall B-DNA structure. The formation of double strands containing up to four free base porphyrins is enabled without compromising duplex stability. UV/vis, fluorescence, and CD spectroscopy demonstrate the formation of porphyrins H-aggregates inside the DNA double helix and provide evidence for the existence of strong excitonic coupling between interstrand stacked porphyrins. H-aggregation results in considerable fluorescence quenching. Most intense CD effects are observed in stacks containing four porphyrins. The findings demonstrate the value of DNA for the controlled formation of molecularly defined porphyrin aggregates

Impedance spectroscopy of OLEDs as a tool for estimating mobility and the concentration of charge carriers in transport layers

The article presents a novel impedance spectroscopy based technique designed to characterise organic light emitting diodes (OLED) during operation. A number of devices based on NPB (N,N′-di(1-naphthyl)-N,N′-diphenyl-(1,1′-biphenyl)-4,4′-diamine) and TPBi (2,2′,2′′-(1,3,5-benzinetriyl)-tris(1-phenyl-1-H-benzimidazole)) conducting layers, CBP (4,4′-bis(N-carbazolyl)-1,1′-biphenyl) as a host and BPTZ-DBTO2 (3,6-bis(10H-phenothiazine-10-yl)-9H-fluorene-[dibenzothiophene-S,S-dioxide]) as an emitter were taken as an example to validate the method. Using equivalent electrical circuits, values of capacitance and conductivity of both hole- (HTL) and electron-transport (ETL) layers were determined and analysed separately. Those parameters, as well as current–voltage characteristics, were used to calculate (i) mobility (μ, cm2 V−1 s−1) of both types of charge carriers, (ii) charge density (n, cm−3) of the charge carriers, and (iii) electric field intensity (E, V m−1) in both transport layers as functions of the applied voltage