An internal charge transfer-dependent solvent effect in V-shaped azacyanines
PBN-AR
Instytucja
Instytut Chemii Fizycznej Polskiej Akademii Nauk
Informacje podstawowe
Główny język publikacji
en
Czasopismo
ORGANIC & BIOMOLECULAR CHEMISTRY
ISSN
1477-0520
EISSN
1477-0539
Wydawca
ROYAL SOC CHEMISTRY
DOI
URL
Rok publikacji
2015
Numer zeszytu
Strony od-do
11714-11720
Numer tomu
13
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Autorzy
(liczba autorów: 1)
Streszczenia
Język
en
Treść
New V-shaped non-centrosymmetric dyes, possessing a strongly electron-deficient azacyanine core, have been synthesized based on a straightforward two-step approach. The key step in this synthesis involves palladium-catalysed cross-coupling of dibromo-N,N[prime or minute]-methylene-2,2[prime or minute]-azapyridinocyanines with arylacetylenes. The resulting strongly polarized [small pi]-expanded heterocycles exhibit green to orange fluorescence and they strongly respond to changes in solvent polarity. We demonstrate that differently electron-donating peripheral groups have a significant influence on the internal charge transfer, hence on the solvent effect and fluorescence quantum yield. TD-DFT calculations confirm that, in contrast to the previously studied bis(styryl)azacyanines, the proximity of S1 and T2 states calculated for compounds bearing two 4-N,N-dimethylaminophenylethynyl moieties establishes good conditions for efficient intersystem crossing and is responsible for its low fluorescence quantum yield. Non-linear properties have also been determined for new azacyanines and the results show that depending on peripheral groups, the synthesized dyes exhibit small to large two-photon absorption cross sections reaching 4000 GM.
Cechy publikacji
ORIGINAL_ARTICLE
Inne
System-identifier
691659
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