1826-11-5Relevant articles and documents
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Dou et al.
, p. 2223 (1967)
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Photoswitching of an intramolecular chiral stack in a helical tetrathiazole
Hashimoto, Yuichiro,Nakashima, Takuya,Shimizu, Daiya,Kawai, Tsuyoshi
, p. 5171 - 5174 (2016)
On-off photoswitching of circularly polarized luminescence was achieved using a pyrene-bearing helical tetrathiazole, in which two pyrene fluorophores stack in a chiral fashion (folded state). The pyrene-excimer based CPL was reversibly controlled by a ge
Boosting free radical type photocatalysis over Pd/Fe-MOFs by coordination structure engineering
Bian, Fengxia,Cheng, Hongmei,Dong, Fan,Jiang, Heyan,Jiang, Yanke,Yang, Lin,Zang, Cuicui
, p. 5543 - 5552 (2021/08/25)
The development of novel heterogeneous photocatalytic systems, along with a deep understanding of the relationship between the catalytic center chemical environment and the catalytic performance, is of great significance. Herein, the surface microenvironment of Pd nanoparticles was modulated with engineered Fe-MOF coordination structures (octahedron MIL-100(Fe), concave octahedron MIL-101(Fe) and irregular lumpy MIL-53(Fe)). Two heterogeneous free radical photocatalytic organic transformations have been developed over Pd nanoparticle loaded Fe-MOFs (Pd/Fe-MOFs). The photocatalytic C-H arylation of thiazole and decarboxylation cross-coupling with cinnamic acid were investigated. Thiazole C-H arylation with halobenzenes was brought about through C-halogen bond activation with the photogenerated electron-rich Pd NPs, the aryl radical generation and the follow-up radical addition. The cinnamic acid decarboxylation cross-coupling was also achieved by means of C-halogen bond activation with photogenerated electron-rich Pd NPs. The base regulated the product stereoselectivity by affecting the balance between cinnamic acid and carboxylate anions, as well as the balance between aryl radicals and the coordination complex intermediates. The improvement of the heterogeneous photocatalytic performance for thiazole C-H arylation and cinnamic acid decarboxylation cross-coupling should be ascribed to the difference in the electron transfer efficiency to Pd NPs over various engineered Fe-O cluster coordination structures. This work highlights the importance of exploiting structure engineering for heterogeneous photocatalytic systems.
Development of Red-Shifted and Fluorogenic Nucleoside and Oligonucleotide Diarylethene Photoswitches
Kolmar, Theresa,Becker, Antonia,Pfretzschner, Ronja A.,Lelke, Alina,J?schke, Andres
supporting information, p. 17386 - 17394 (2021/10/20)
The reversible modulation of fluorescence signals by light is of high interest for applications in super-resolution microscopy, especially on the DNA level. In this article we describe the systematic variation of the core structure in nucleoside-based diarylethenes (DAEs), in order to generate intrinsically fluorescent photochromes. The introduction of aromatic bridging units resulted in a bathochromic shift of the visible absorption maximum of the closed-ring form, but caused reduced thermal stability and switching efficiency. The replacement of the thiophene aryl unit by thiazol improved the thermal stability, whereas the introduction of a benzothiophene unit led to inherent and modulatable turn-off fluorescence. This feature was further optimized by introducing a fluorescent indole nucleobase into the DAE core, resulting in an effective photoswitch with a fluorescence quantum yield of 0.0166 and a fluorescence turn-off factor of 3.2. The site-specific incorporation into an oligonucleotide resulted in fluorescence-switchable DNA with high cyclization quantum yields and switching efficiency, which may facilitate future applications.
