Search results for "ANTHRACENE"
showing 10 items of 171 documents
Fluorescence of Newo-Carborane Compounds with Different Fluorophores: Can it be Tuned?
2014
Two sets of o-carborane derivatives incorporating fluorene and anthracene fragments as fluorophore groups have been successfully synthesized and characterized, and their photophysical properties studied. The first set, comprising fluorene-containing carboranes 6-9, was prepared by catalyzed hydrosilylation reactions of ethynylfluorene with appropriate carboranylsilanes. The compound 1-[(9,9-dioctyl-fluorene-2-yl)ethynyl]carborane (11) was synthesized by the reaction of 9,9-dioctyl-2-ethynylfluorene and decaborane (B10H14). Furthermore, reactions of the lithium salt of 11 with 1 equivalent of 4-(chloromethyl)styrene or 9-(chloromethyl)anthracene yielded compounds 12 and 13. Members of the se…
Fragmentation of anthracene C14H10, acridine C13H9N and phenazine C12H8N2 ions in collisions with atoms
2014
International audience; We report experimental total, absolute, fragmentation cross sections for anthracene C14H10, acridine C13H9N, and phenazine C12H8N2 ions colliding with He at center-of-mass energies close to 100 eV. In addition, we report results for the same ions colliding with Ne, Ar, and Xe at higher energies. The total fragmentation cross sections for these three ions are the same within error bars for a given target. The measured fragment mass distributions reveal significant contributions from both delayed (≫10−12 s) statistical fragmentation processes as well as non-statistical, prompt (∼10−15 s), single atom knockout processes. The latter dominate and are often followed by sec…
Ion-Pairing Effects in the Self-Assembly of a Fluorescent Pseudorotaxane
2006
Herein we report on the self-assembly, in a low polarity solvent, of a pseudorotaxane species comprising binaphthyl-26-crown-8 (BN26C8) as the macrocyclic host and anthracenyl-benzylammonium as the threadlike positively charged guest (ABH+). Absorption and luminescence data reveal a very efficient energy transfer process occurring from the binaphthyl to the anthracene singlet excited states. The self-assembly is highly dependent on the nature of the counteranion confirming the crucial role played by it in the competition between the self-assembly process and the formation of ion pairs (ABH+X-). This behavior can be readily evidenced in dilute solutions from the analysis of the luminescence …
Effect of molecular geometry and extended conjugation on the performance of hydrogen-bonded semiconductors in organic thin-film field-effect transist…
2021
A general synthetic method has been used for the condensation of the 7-azaindole substructure at both extremes of centrosymmetric fused polyheteroaromatic systems. Four different aromatic spacers (benzene, naphthalene, anthracene and pyrene) that modify the molecular geometry and the π-conjugated surface have proved the ability of 7-azaindole to work as a building block that can control the crystal packing through reciprocal hydrogen bond interactions. Two possible self-assembled columnar arrangements have been observed as a result of the π–π interactions between hydrogen-bonded ribbon-like supramolecular structures. A detailed comparative analysis of the molecular organisation driven by hy…
Inhibitoren der Korrosion (11). Nachweis der auf Eisengrenzflächen gebildeten Sekundärinhibitoren durch UV-Absorptions- und Fluoreszenzspektroskopie
1972
Aus Triphenylbenzylphosphoniumchlorid bildet sich in saurer Losung auf der Eisenoberflache eine Schicht, die aufgrund der UV-Reflexionsspektroskopie mit Triphenylphosphin identisch sein durfte. Auch das Mono- und Bis-Phosphoniumsalz wird an der Eisengrenzflache reduktiv abgebaut; die dabei entstehenden Anthracenderivate werden auf dieselbe Weise identifiziert. Es handelt sich um Methylanthracen. Die zur weiteren Aufgliederung der Reaktionsprodukte vorgenommene dunnschicht-chromatografische Auftrennung (Untersuchung des Extrakts in Cyclohexanol und Methanol) ergibt kein sich deutlich unterscheidenden Fluoreszenzspektren. Identification, by UV absorption and fluorescence spectroscopy, of the …
Density functional theory studies of OH-modified open-ended single-wall zigzag carbon nanotubes (SWCNTs)
2010
Abstract Functionalized carbon nanotubes (CNTs) are often formed as result of oxidation and cleaning of raw product grown on metal catalyst. Structure and energy of ideal and OH-modified single-wall nanotubes (SWCNTs) of different length (2.8, 7.0 and 13.5 A) were obtained at the DFT-B3LYP level. From one to nine OH groups were added at the end of the nanotube and a nonadditive dependence of attachment energy on the number of substituents was observed. The energetics of SWCNT end substitution with OH groups was supported by high level MP2 and CCSD(T) determination of reaction energy: R – H + 1 / 2 O 2 → R – OH + Δ E for methane, benzene and anthracene. In addition, a vibrational analysis of…
Optical Switching and Antenna Effect of Dendrimers with an Anthracene Core
2007
Dendrimers 6G(i) (i=1-4) consisting of an anthracene core and Fréchet dendrons which are attached via a CH(2)OCH(2) chain in the 9-position undergo quantitative and completely reversible intramolecular [4pi+4pi] cycloaddition. The process can be monitored by absorption and fluorescence measurements. The Fréchet dendrons act as an energy funnel that collects and focuses the photon energy but does not change the photostationary states, which for both directions are completely on the product side when the separate chromophores are selectively irradiated. The quantum yields of anthracene fluorescence and of singlet energy transfer from the dendrons to the core were studied as a function of dend…
Radioactively labelled epoxides. part V. Tritium labelled K-region oxides and trans-dihydrodiols of pyrene, benzo[a]pyrene and dibenz[a, h]anthracene
1987
Tritium labelled K-region oxides of pyrene, benzo[a]pyrene and dibenz[a,h]anthracene have been prepared by cyclization of the corresponding trans-dihydrodiols which were obtained by reduction of K-region quinones with sodium borotritide in the presence of oxygen. This synthetic pathway not only yields two metabolically important radioactively labelled derivatives of polycyclic aromatic hydrocarbons in a simple and efficient manner, but also requires a rather inexpensive source of tritium.
Anthracene-containing PPE-PPV copolymers: Effect of side-chain nature and length on photophysical and photovoltaic properties
2009
Rupali Jadhav1,2, Stefan Turk3, Florian Kuhnlenz1, Vera Cimrova4, Silke Rathgeber5, Daniel A. M. Egbe*,2,3, and Harald Hoppe**,1 1 Institute of Physics, Ilmenau University of Technology, Weimarer Str. 32, 98693 Ilmenau, Germany 2 Linz Institute for Organic Solar Cells (LIOS), Johannes Kepler University Linz, Altenbergerstr. 69, 4040 Linz, Austria 3 Institute for Print and Media Technology, Chemnitz University of Technology, Reichenhainer Str. 70, 09126 Chemnitz, Germany 4 Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovský Sq. 2, 162 06 Prague 6, Czech Republic 5 Johannes Gutenberg-University Mainz, Staudingerweg 7, 55128 Mainz, Germany
Anthracene Fluorescence Quenching by a Tetrakis (Ketocarboxamide) Cavitand
2014
Quenching of both fluorescence lifetime and fluorescence intensity of anthracene was investigated in the presence of a newly derived tetrakis (ketocarboxamide) cavitand at various concentrations. Time-correlated single photon counting method was applied for the lifetime measurements. A clear correlation between the fluorescence lifetime of anthracene as a function of cavitand concentration in dimethylformamide solution was observed. The bimolecular collisional quenching constant was derived from the decrease of lifetime. Fluorescence intensity was measured in the emission wavelength region around 400 nm as a result of excitation at 280 nm. Effective quenching was observed in the presence of…