1 Ocak 2004 Dergi makalesi Açık Erişim

Zhao, L; Perepichka, IF; Turksoy, F; Batsanov, AS; Beeby, A; Findlay, KS; Bryce, MR

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  <dc:creator>Zhao, L</dc:creator>
  <dc:creator>Perepichka, IF</dc:creator>
  <dc:creator>Turksoy, F</dc:creator>
  <dc:creator>Batsanov, AS</dc:creator>
  <dc:creator>Beeby, A</dc:creator>
  <dc:creator>Findlay, KS</dc:creator>
  <dc:creator>Bryce, MR</dc:creator>
  <dc:date>2004-01-01</dc:date>
  <dc:description>A series of 2,5-di(aryleneethynyl) pyrazine derivatives has been synthesised in 23-41% yields by two-fold reaction of 2,5-dibromo-3,6-dimethylpyrazine 3 with ethynylarenes (arene=phenyl, 2-pyridyl, 4-ethylphenyl, 4-chlorophenyl, 4-biphenyl) under standard Sonogashira conditions [CuI, Pd(PPh3)(2)C(l)2, NEt3, THF]. Compound 3 has been converted into 2,5-diethynyl-3,6-dimethylpyrazine, which reacts with 2-iodothiophene to yield 2,5-bis(thien-2-ylethynyl)-3,6-dimethylpyrazine. In the X-ray crystal structure of 2,5-di(phenylethynyl)-3,6-dimethylpyrazine 4 the two phenyl rings are parallel and the pyrazine ring is inclined to their planes by 14.2degrees. Quantum chemical calculations establish that the HOMO-LUMO gap for 4 (3.56 eV) is lower than that of di(phenylethynyl) benzene 12 (3.72 eV). The nitrogen atoms of 4 serve to localise the HOMO on the central ring's carbon atoms, resulting in a quinoidal-type population, in contrast to 12. Cyclic voltammetric studies establish that 4 undergoes a reduction to the radical anion at ca. -1.9 V (vs. Ag/Ag+ in MeCN), which is almost reversible at high scan rates (500 mV s(-1)). The UV-vis absorption and photoluminescence profiles of 4 in cyclohexane are similar to those of 12; the emission for 4 (lambda(max) 379 and 395 nm) is red-shifted compared to 12. Single-layer OLEDs using MEH-PPV as the emissive polymer show significantly enhanced external quantum efficiencies (up to 0.07%) when 20% by weight of 2,5-di(biphenyl-4-ethynyl)-3,6-dimethylpyrazine 8 is added as a dopant: this is ascribed to the enhanced electron-transporting properties of the pyrazine system.</dc:description>
  <dc:identifier>https://aperta.ulakbim.gov.trrecord/94797</dc:identifier>
  <dc:identifier>oai:zenodo.org:94797</dc:identifier>
  <dc:rights>info:eu-repo/semantics/openAccess</dc:rights>
  <dc:rights>http://www.opendefinition.org/licenses/cc-by</dc:rights>
  <dc:source>NEW JOURNAL OF CHEMISTRY 28(8) 912-918</dc:source>
  <dc:title>2,5-di(aryleneethynyl)pyrazine derivatives: synthesis, structural and optoelectronic properties, and light-emitting device</dc:title>
  <dc:type>info:eu-repo/semantics/article</dc:type>
  <dc:type>publication-article</dc:type>
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