http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
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>
Giant Magnetoimpedance in Co67Fe₄Mo1.5Si16.5B₁₁ Metallic Glass Ribbon
M. Kuźmiński,K. Nesteruk,H. K. Lachowicz,A. Krzyżewski,Seong-Cho Yu,Heebok Lee,Cheol Gi Kim 한국자기학회 2004 Journal of Magnetics Vol.9 No.2
Giant magneto-impedance (GMI) effect in zero-magnetostrictive Co-based amorphous ribbons samples in their as-quenched and stress-released states as well as with intentionally induced magnetic anisotropy were investigated. Magnetic and impedance properties of the samples exhibiting different anisotropy were compared and the optimum operation conditions for the studied samples from the view-point of their utilization as a sensor element have been determined. A design of a model of magnetic field sensor and characteristics of the constructed prototype are presented.
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>