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RISS 인기검색어
- 검색키워드
- 저자 : Tasior, Mariusz (검색결과 4 건)
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Tasior, Mariusz,Hassanein, Khaled,Mazur, Leszek M.,Sakellari, Ioanna,Gray, David,Farsari, Maria,Samoć,, Marek,Santoro, Fabrizio,Ventura, Barbara,Gryko, Daniel T. The Royal Society of Chemistry 2018 Physical chemistry chemical physics Vol.20 No.34
<P>A three-step synthetic route to a structurally unique π-expanded pyrrolo[3,2-<I>b</I>]pyrrole derived bis-ketone has been developed. In contrast to all previous ladder-type pyrrolopyrroles, the new dye exhibits a low-energy absorption band in the visible region which is responsible for its red-purple color. Interestingly, even though the compound is centrosymmetric, this band coincides with the lowest energy two-photon absorption (TPA) transition. This non-typical behaviour has been computationally rationalized by finding two close lying excited states, one of which (S1) is active for OPA and the other (S2) for TPA processes, which arise from the mixing of two symmetric partial charge-transfer states. The ultrafast excited-state dynamics was characterized by means of transient absorption analysis. A relaxation process involving S1 symmetry breaking occurs in a few ps, leading to the formation of the lowest energy charge-transfer state. This is weakly emitting, with a measured lifetime in the order of tens of picoseconds. Interestingly, two-photon polymerization has been achieved using this new ketone. The high yield of radical photo-initiation upon two-photon excitation was demonstrated by the fabrication of woodpile photonic crystal templates by direct laser writing using a zirconium-silicon hybrid composite.</P>
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π-Expanded coumarins: synthesis, optical properties and applications
Tasior, Mariusz,Kim, Dokyoung,Singha, Subhankar,Krzeszewski, Maciej,Ahn, Kyo Han,Gryko, Daniel T. The Royal Society of Chemistry 2015 Journal of Materials Chemistry C Vol.3 No.7
<P>Coumarins fused with other aromatic units have recently emerged as a hot topic of research. Their synthesis is partly based on classical methodologies such as Pechmann reaction or Knoevenagel condensation, but it also sparked the discovery of completely new pathways. In very recent years so-called vertically expanded coumarins were synthesized, effectively expanding the portfolio of existing architectures. A subtle relationship exists between the structure of fused coumarins and their optical properties. Although absorption of UV-radiation and light is a unifying theme among these π-expanded coumarins, the fluorescence properties strongly depend on the structure. The mode of fusion, the type of additional ring and the presence of electron-donating and electron-withdrawing substituents all influence the photophysical parameters. Recent advances made it possible to modulate their absorption from 300 nm to 550 nm, resulting in new coumarins emitting orange light. This review serves as a guide through both synthesis strategies and structure-property relationship nuances. Strong intramolecular charge-transfer character made it possible to reach suitable values of two-photon absorption cross-section. Photophysical advantages of π-expanded coumarins have been already utilized in fluorescent probes and two-photon excited fluorescence microscopy.</P>
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An internal charge transfer-dependent solvent effect in V-shaped azacyanines
Tasior, Mariusz,Bald, Ilko,Deperasiń,ska, Irena,Cywiń,ski, Piotr J.,Gryko, Daniel T. The Royal Society of Chemistry 2015 Organic & Biomolecular Chemistry Vol.13 No.48
<P>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-<I>N</I>,<I>N</I>′-methylene-2,2′-azapyridinocyanines with arylacetylenes. The resulting strongly polarized π-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 S<SUB>1</SUB> and T<SUB>2</SUB> states calculated for compounds bearing two 4-<I>N</I>,<I>N</I>-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.</P> <P>Graphic Abstract</P><P>Intramolecular charge transfer dictates linear and non-linear optical properties of D–π-A<SUP>+</SUP>–π-D compounds. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c5ob01633a'> </P>
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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>
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