http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : Friese Daniel H. (검색결과 2 건)
- 무료
- 기관 내 무료
- 유료
-
Purc, Anna,Koszarna, Beata,Iachina, Irina,Friese, Daniel H.,Tasior, Mariusz,Sobczyk, Krzysztof,Pę,dziń,ski, Tomasz,Brewer, Jonathan,Gryko, Daniel T. Royal Society of Chemistry 2017 ORGANIC CHEMISTRY FRONTIERS Vol.4 No.5
<▼1><P>Benzofuran has been proven to be the versatile substituent for tuning the optics of diketopyrrolopyrroles.</P></▼1><▼2><P>An in-depth investigation of the reaction of substituted salicylaldehydes with chloroacetonitrile led to the development of new conditions for the synthesis of 2-cyanobenzofurans. The crucial improvement lies in the use of phase-transfer catalysis in the second step, <I>i.e.</I>, intramolecular aldol type condensation. In a two-step process, the reactants were transformed into a library of 3,6-bis(benzofuran-2-yl)diketopyrrolopyrroles. We show that the presence of a methyl group in a position adjacent to the cyano functionality only slightly decreased the yield of diketopyrrolopyrroles (to 30–57%). An analysis of the relationship between the degree of polarization/planarization of aryl-diketopyrrolopyrroles and their one- and two-photon spectroscopic properties is reported. Careful design of the desired dyes and enhanced control of their ability to assume a planar molecular structure resulted in interesting photophysical properties, such as absorption and emission in the so-called biological window. Despite having less promising linear spectroscopic properties, the deplanarized molecules possess pretty strong two-photon absorbing properties. Placing methyl groups at adjacent positions to the linkage between benzofuran and the DPP core caused the formation of yellow-emitting dyes with almost quantitative fluorescence quantum yield, moderate Stokes shift and reasonable two-photon absorption cross-sections.</P></▼2>
-
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>
연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
