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Novel symmetrical anthracene derivatives with bulky carbazolyl-fluorene, diphenylamino-fluorene, or carbazolyl-carbazole units connected to the anthracene frame through an ethynyl bridge were synthesized in excellent yield by using Sonogashira cross-coupling. The ethynyl bridge in the anthracene dyes increases π-electron conjugation and the bulky substituents considerably attenuate intermolecular interactions. The dyes possess high thermal stability, tremendous solubility in common organic solvents, and especially high photoluminescence quantum yield ( Φf) in solution in the range of 77-98 %. OLED devices were fabricated. The AFM images of thin films and blends prepared from all compounds show a uniform and flat surface, indicating excellent film-forming properties. Devices incorporating the anthracene derivative with diphenylamino-fluorene end-capping groups exhibited the highest value of current density ( J). All of the fabricated OLED devices emitted yellowish-orange light under applied voltage. [ABSTRACT FROM AUTHOR]

A series of small donor-acceptor (D-A) systems based on quinoline derivatives bearing a fluorenyl motif were synthesized through Ru-catalyzed reactions. Their photophysical, electrochemical, and structural properties were investigated deeply. The photoluminescence spectra of most of the compounds were characterized by an intense band at λ ≈ 400 nm, whereas a redshifted band occurred at λ = 560 nm if the substituent of the quinoline was changed to the strongly electron-withdrawing NO2 group. Most of the synthesized compounds exhibited appealing luminescence and electrical properties, which might make them useful materials for photovoltaics. Preliminary electrical conductivity measurements of indium tin oxide/compound/Al devices showed that the current is enhanced as the applied voltage increases and, therefore, proved the semiconducting properties of the investigated compounds. Moreover, one of the synthesized compound was tested as a component of the active layer in a bulk heterojunction (BHJ) solar cell, and a power conversion efficiency (PCE) of 0.25 % was obtained. [ABSTRACT FROM AUTHOR]

New quinolines bearing a 2,2′-bithiophene motif have been prepared through Ru- and In-catalyzed reactions as well as by Suzuki cross-coupling reactions. The novel quinolines have been characterized by using EI-HRMS and NMR spectroscopy. Additionally, the molecular structures of the novel quinolines were confirmed by X-ray crystallography. The photophysical and electrochemical properties of all quinoline derivatives were investigated by using absorption and luminescence spectroscopy and cyclic voltammetry. The main intense absorption bands associated with the quinoline derivatives were located between 350 and 450 nm. Intense blue-green and orange-red fluorescence, moderate Stokes shifts, and microsecond lifetimes were observed. Quinolines containing one bithiophene moiety underwent oxidation leading to dimerization, whereas bis(bithiophenyl)-substituted quinoline underwent polymerization. All the studied quinolines showed multistep reversible reduction, with 6-nitro-4-phenylquinoline being the easiest to reduce. The study of novel quinoline derivatives indicates a strong correlation between their electrochemical and spectroscopic properties and the character of the substituent (electron-donating or electron-withdrawing) in the quinoline ring. [ABSTRACT FROM AUTHOR]

A series of new π-conjugated donor (thienyl – T) and acceptor (A) oligomers were prepared by Stille coupling reaction. The T–A oligomers consisting of thiophene/bithiophene as donors and 1,2,4-triazine as an acceptor were prepared to investigate their photophysical and electrochemical properties. These compounds were spectroscopically confirmed to be highly conjugated. These UV-vis data show that the number and position of the thiophene considerably affect the width of the HOMO–LUMO gap and the rigidity of the conjugated system. Compounds A2TA, A3TA, A4TA show photoluminescence in a range 466–543 nm. [ABSTRACT FROM AUTHOR]

A highly selective rhodium and ruthenium catalyzed transformation of N-allylamines and N-allylamides to the corresponding 1-propenyl derivatives is described. Strong E-selectivity in the isomerization of allylamines was observed. The first catalytic system containing a transition metal complex for Z-selective isomerization of allylamides is presented. An application of siliceous mesoporous cellular foams for effective removal of the catalyst from the post-reaction mixture is described. [Copyright &y& Elsevier]

Reactions of S&z.sbnd;allyl systems (allyl sulphides of R&z.sbnd;S&z.sbnd;allyl type, where R=Et, allyl, Ph, Me3C, Ph3C, as well as of allyl phenyl sulphoxide, allyl phenyl sulphone, 2,5-dihydro-1,1-dioxothiophene) with [RuClH(CO)(PPh3)3] and other ruthenium compounds have been investigated. Double-bond migration was observed in the case of allyl trityl sulphide, allyl t-butyl sulphide and both sulphones, that is, where co-ordinating properties of sulphur were not too strong. High-yielded syntheses of (E)- and (Z)-R&z.sbnd;S&z.sbnd;CH&z.dbnd6;CHCH3 (R=Me3C, Z:E=96:4 and Ph3C, Z:E=92:8), (E)&z.sbnd;Ph&z.sbnd;S(O2)&z.sbnd;CH&z.dbnd6;CHCH3 and 2,3-dihydro-1,1-dioxothiophene from respective allyl systems are described. The binuclear Ru complex, formed in the model reaction of allyl phenyl sulphide with [RuClH(CO)(PPh3)3] has been isolated and its structure has been resolved. The mechanism of the reaction between S&z.sbnd;allyl systems and [RuClH(CO(PPh3)3] is proposed. [Copyright &y& Elsevier]

NˆCˆN cyclometalated iridium(III) acetylide complexes in the 3 + 2+1 ligand mode were obtained and characterized. Cyclometalating ligands were bis(pyridyl)phenyl, bis(benzothiazolyl)phenyl and 2-phenylpyridine derivatives, while acetylene ligands represented 2-ethynylfluorene and 3-ethynylcarbazole derivatives. The HOMOs of the ethynyl iridium complexes are located on the ethynyl ligand and the iridium atom, whereas the LUMO is located exclusively on the NˆCˆN-cyclometalating ligand. All compounds showed phosphorescent properties, where the change of ligands significantly affects the wavelength of emission. Acetylide complexes emit light from the blue (∼ 400 nm) to orange (∼ 560 nm) range. Emission occurs from the mixed state 3MLCT/3LC, with a predominance of junction depending on the structure of the ligands. Image 1 • Iridium acetylide complexes with fluorene and carbazole motifs were examined. • Detailed characterization of optical, thermal and electrochemical properties of new complexes has been carried out. • In the Ir(III) complexes the emission takes place from the mixed state 3MLCT/3LC. [ABSTRACT FROM AUTHOR]

The course of the reaction of alkalide K-, K+(15-crown-5)2 1 with selected alcohols depends on the kind of alcohol and the mode of substrate delivery. In the case of methanol, potassium methoxide formed initially undergoes destruction at the excess of 1. It results in potassium oxide and methylpotassium. The latter opens the crown ether ring giving potassium tetraethylene glycoxide vinyl ether and methane. A similar course of the process is observed for propanol. Potassium glycidoxide is the main product formed in the reaction of 1 with glycidol. Its oxirane ring is opened at the excess of 1. Organopotassium alkoxides, i.e., potassium potassiomethoxide and dipotassium potassiopropane-1,2-dioxide are intermediate products of this reaction. They react then with the crown ether. Potassium methoxide, potassium enolate of acetaldehyde, dipotassium propane-1,2-dioxide and potassium tetraethylene glycoxide vinyl ether are the final products of this process. [Copyright &y& Elsevier]

The kind of substituent in alkyl glycidyl ethers affects the course of their reaction with K−, K+(15-crown-5)2. The cyclic oxirane ring is exclusively cleaved in the case of butyl glycidyl ether whereas the presence of the unsaturated allyl group in the glycidyl ether molecule unexpectedly prefers the scission of the linear ether bond. In both the systems organometallic intermediates are formed. They react with crown ether causing its ring opening. Allylpotassium formed from allyl glycidyl ether reacts also with another glycidyl ether molecule; the oxirane ring is opened in this case. [Copyright &y& Elsevier]