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RISS 인기검색어
- 검색키워드
- 저자 : Banasiewicz, M. (검색결과 5 건)
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Orłowski, Rafał,Banasiewicz, Marzena,Clermont, Guillaume,Castet, Fré,dé,ric,Nazir, Rashid,Blanchard-Desce, Mireille,Gryko, Daniel T. The Royal Society of Chemistry 2015 Physical chemistry chemical physics Vol.17 No.37
<P>We describe the design, synthesis, and fluorescent profile of two environment-sensitive dyes in which an electron-donating group is conjugated to an electron-accepting unit <I>via</I> a pyrrolo[3,2-<I>b</I>]pyrrole ring system. The maximum emission wavelength (<I>λ</I><SUB>em</SUB>) of these donor–donor–acceptor (D–D–A) pyrrolo[3,2-<I>b</I>]pyrroles was found to be very sensitive to the environment (a bathochromic shift of about 100 nm in polar solvents). The longer emission wavelength in polar aprotic as well as hydrophilic solvents compared with that in low-polarity hydrophobic solvents was due to an ICT character of the excited state. The Stokes shift increased in both cases following the polarity differences, reaching ∼7000 cm<SUP>−1</SUP> in MeOH for the compound possessing a cyano group and dimethylamino groups at the periphery. Interestingly, the two-photon absorption responses were also found to be quite sensitive to solvent polarity with an increase by a factor of about 2 on going from an apolar solvent to a highly polar protic or aprotic solvent.</P> <P>Graphic Abstract</P><P>The pyrrolo[3,2-<I>b</I>]pyrrole core was determined to be an efficient linker allowing the conjugation of peripheral benzene rings. The resulting dipolar compounds displayed strong solvatochromism of fluorescence. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c5cp03523f'> </P>
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Łukasiewicz, Łukasz G.,Ryu, Hye Gun,Mikhaylov, Alexander,Azarias, Cloé,Banasiewicz, Marzena,Kozankiewicz, Bolesław,Ahn, Kyo Han,Jacquemin, Denis,Rebane, Aleksander,Gryko, Daniel T. Wiley (John WileySons) 2017 Chemistry, an Asian journal Vol.12 No.14
<P>Five centrosymmetric and one dipolar pyrrolo[3,2-b]pyrroles, possessing either two or one strongly electron-withdrawing nitro group have been synthesized in a straightforward manner from simple building blocks. For the symmetric compounds, the nitroaryl groups induced spontaneous breaking of inversion symmetry in the excited state, thereby leading to large solvatofluorochromism. To study the origin of this effect, the series employed peripheral structural motifs that control the degree of conjugation via altering of dihedral angle between the 4-nitrophenyl moiety and the electron-rich core. We observed that for compounds with a larger dihedral angle, the fluorescence quantum yield decreased quickly when exposed to even moderately polar solvents. Reducing the dihedral angle (i.e., placing the nitrobenzene moiety in the same plane as the rest of the molecule) moderated the dependence on solvent polarity so that the dye exhibited significant emission, even in THF. To investigate at what stage the symmetry breaking occurs, we measured two-photon absorption (2PA) spectra and 2PA cross-sections (sigma(2PA)) for all six compounds. The 2PA transition profile of the dipolar pyrrolo[3,2-b]pyrrole, followed the corresponding one-photon absorption (1PA) spectrum, which provided an estimate of the change of the permanent electric dipole upon transition, approximate to 18D. The nominally symmetric compounds displayed an allowed 2PA transition in the wavelength range of 700-900nm. The expansion via a triple bond resulted in the largest peak value, sigma(2PA)=770GM, whereas altering the dihedral angle had no effect other than reducing the peak value two- or even three-fold. In the S0S1 transition region, the symmetric structures also showed a partial overlap between 2PA and 1PA transitions in the long-wavelength wing of the band, from which a tentative, relatively small dipole moment change, 2-7D, was deduced, thus suggesting that some small symmetry breaking may be possible in the ground state, even before major symmetry breaking occurs in the excited state.</P>
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Bidirectional Solvatofluorochromism of a Pyrrolo[3,2-<i>b</i>]pyrrole-Diketopyrrolopyrrole Hybrid
Ryu, Hye Gun,Mayther, Maximillian F.,Tamayo, Jesse,Azarias, Cloé,Espinoza, Eli M.,Banasiewicz, Marzena,Łukasiewicz, Łukasz G.,Poronik, Yevgen M.,Jeż,ewski, Artur,Clark, John,Derr, James B. American Chemical Society 2018 The Journal of Physical Chemistry Part C Vol.122 No.25
<P>Hybridization of electron donors and acceptors provides routes to long-wavelength absorbing and fluorescing dyes. Varying the coupling of low-lying charge-transfer (CT) states with the ground and different locally excited states profoundly affects the photophysics of such donor-acceptor conjugates. Herein, we hybridize an electron-deficient diketopyrrolopyrrole (DPP) moiety with an electron-rich pyrrolopyrrole (PP) that is symmetrically N-arylated with 4-nitrophenyl substituents. The lowest Franck-Condon state is located on the DPP ring structure and dominates the photophysics of the hybrid. Similar to the DPP moiety, the hybrid exhibits optical absorption that is invariant to the solvent media. The PP donor considerably modulates its fluorescence by undergoing electron transfer to the locally excited DPP to form a CT state. For nonpolar media, an increase in solvent polarity causes a bathochromic shift of the fluorescence reaching the longest wavelengths for chloroform and DCM. A further increase in the medium polarity moves the fluorescence maximum hypsochromically back to where it is for alkane solvents. This bidirectional solvatofluorochromism accompanies a polarity-induced increase in the nonradiative decay rates leading to a decrease in the emission quantum yield. The solvent dependence of the energy level of the CT state is responsible for the observed polarity-induced fluorescence behavior of the hybrid. This emission behavior, along with the solvent invariance of the absorption, results in multimodal sensitivity to the solvation environment.</P> [FIG OMISSION]</BR>
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Solvatofluorochromic, non-centrosymmetric π-expanded diketopyrrolopyrrole
Grzybowski, Marek,Jeż,ewski, Artur,Deperasiń,ska, Irena,Friese, Daniel H.,Banasiewicz, Marzena,Hugues, Vincent,Kozankiewicz, Bolesław,Blanchard-Desce, Mireille,Gryko, Daniel T. The Royal Society of Chemistry 2016 Organic & Biomolecular Chemistry Vol.14 No.6
<P>A novel non-centrosymmetric π-expanded diketopyrrolopyrrole was designed and synthesized. Strategic placement of <I>tert</I>-butyl groups at the periphery of a diketopyrrolopyrrole allowed us to selectively fuse one moiety <I>via</I> tandem Friedel–Crafts-dehydration reactions, resulting in a non-centrosymmetric dye. The structure of the dye was confirmed by X-ray crystallography, revealing that it contains a nearly flat arrangement of four fused rings. Extensive photophysical studies of this new functional dye revealed that the intensity of its emission strongly depends on solvent polarity, which is typical for dipolar chromophores. In non-polar solvents, the fluorescence quantum yield is high whereas in polar solvents such as MeOH, it is 12%. However, upon two-photon excitation the compound behaves like a centrosymmetric dye, showing a two-photon absorption maximum at significantly shorter wavelengths than twice the wavelength of the one-photon absorption maximum.</P> <P>Graphic Abstract</P><P>A donor–acceptor type π-expanded diketopyrrolopyrrole behaves as non-centrosymmetric as far as linear optical properties are concerned but as ‘pseudo-symmetric’ for two-photon absorption. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c5ob02583d'> </P>
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