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Showing 1 to 13 of 13 for “"Acenes"”.
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In Pursuit of Extraordinarily Twisted Acenes
Longitudinally twisted acenes are a topologically interesting class of polycyclic aromatic hydrocarbons (PAHs), and it could be argued that they have quite beautiful chemical structures, too. X-ray crystal analysis of many of these acenes has found them to adopt a helical conformation where the …
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Chemistry of acenes, [60]fullerenes, cyclacenes and carbon nanotubes
… the present work, we studied the chemistries of acenes, cyclacenes, [60]fullerenes and CNTs. Acenes are well known organic semiconductors. Pentacene is a benchmark organic semiconductor due to low HOMO-LUMO gap and high charge carrier mobilities in its thin film. Its poor solubility and …
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Thermolysis of multiply-methylated acenes : experiments and mechanicstic modelling
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 1996.
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Computational and experimental studies of acenes, starphenes and [60]fullerene derivatives
<p>The computational and experimental studies of acenes, starphenes and [60]fullerene derivatives is described. Acenes are promising organic semiconductors. Hybrid density functional theory applying a triple-zeta valence basis set (B3LYP/6-311+G**) has been used to approximate the HOMO - LUMO …
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Fullerene-acene chemistry: Part I Studies on the regioselective reduction of acenes and acene quinones; Part II Progress toward the synthesis of large acenes and their Diels-Alder chemistry with [60]fullerene
<p>The regioselective reduction of acenes and acene quinones has been studied. Using hydriodic acid (HI) in acetic acid (HOAc) as reductant, it was found that acenes smaller than five rings reduce in a regioselective fashion. It was also found that phenyl substituted acenes with as many as seven …
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Probing regioselectivity in the Diels -Alder cycloadditions between *[60]fullerene and aryl substituted acenes
… of [60]fullerene across phenyl substituted acenes. [60]Fullerene shows an unusual propensity for cycloaddition across the 5,12 position of 15 and the 5,14 and 7,12 positions of 22. This reactivity is compared and contrasted to the reactivity of other dienophiles including dimethyl …
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Quantum mechanical origin of the plasmonic properties of noble metal nanoparticles
… The high-energy, high-intensity beta-peak of acenes also results from a constructive addition of single-particle transitions and I show that it can be assigned to a plasmon. I also show that the plasmon modes of both acenes and metallic nanoparticles can be described with a simple …
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Investigating the Photophysics of New and Stable Singlet Fission Materials
… fission materials: via benzannulation of acenes in TTBP or via excited state aromaticity in INDTs. Our characterisation of TTBP leads to a new design principle for reducing non-radiative voltage losses by maximising photoluminescence yield. The final study on tetracene derivatives …
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Hydrogenation of nanostructured carbon, synthesis of organic semiconductors and progress towards synthesis of fullerenes and nanoribbons from polyaromatic hydrocarbons
… analysis difficult.</p><p>The synthesis of acenes, bisacenes and periacenes was accomplished. Unsubstituted bipentacene was successfully synthesized for the first time and showed improved solubility compared to pentacene. Peripentacenequinone was also synthesized, a stable organic …
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Pushing the Boundaries of Endothermic Singlet Fission in Organic Semiconductors through Structure and Energetic Control
… and energetics. SF occurs via two steps in acenes: a photoexcited singlet, S1, decays to form TT, and TT breaks into two free triplets, T1. The role played by morphology or the local geometry of molecules in triplet generation via SF is vital, as the process depends on the placement of …
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Synthesis and analysis of siloranes for use as a biomaterial and extended twisted molecular ribbons
… was then studied on the aromatized isopropyl acenes utilizing VT-NMR spectroscopy. Coalescence of the methyl peaks in the 1H NMR spectrum was not observed at temperatures up to 408 K. Utilizing this method, the barrier to enantiomerization of these compounds was found to be greater than 24.0 …
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LINEARLY EXTENDED PYRYLIUM SALTS (LEPS) AND LINEARLY EXTENDED THIOPYRYLIUM SALTS (LETS) AS ORGANIC SEMICONDUCTORS
… combine linearly conjugated π-systems of acenes with the highly electron-deficient nature of pyrylium and thiopyrylium salts. The LEPS and LETS compounds described here were synthesized efficiently using new reactions. Their properties were calculated through high-level computation and …
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Alkynylated acenothiadiazoles and N-heteroacenes: synthesis, functionalization, and study of the optical properties for optoelectronic and sensory materials
… towards oxygen and moisture. Alkynylated N-Heteroacenes fulfill many of these requirements. Substitution with alkyne groups as well as the introduction of the pyrazine subunit both inhibits oxidative degradation at sensitive position in the molecules. Additionally the trialkylsilylethynyl group …