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.
Switching between mono and doubly reduced odd alternant hydrocarbon: designing a redox catalyst
Ahmed, Jasimuddin,Datta, Paramita,Das, Arpan,Jomy, Stephy,Mandal, Swadhin K.
, p. 3039 - 3049 (2021/03/14)
Since the early Hückel molecular orbital (HMO) calculations in 1950, it has been well known that the odd alternant hydrocarbon (OAH), the phenalenyl (PLY) system, can exist in three redox states: closed shell cation (12π e?), mono-reduced open shell neutral radical (13π e?) and doubly reduced closed shell anion (14π e?). Switching from one redox state of PLY to another leads to a slight structural change owing to its low energy of disproportionation making the electron addition or removal process facile. To date, mono-reduced PLY based radicals have been extensively studied. However, the reactivity and application of doubly reduced PLY species have not been explored so far. In this work, we report the synthesis of the doubly reduced PLY species (14π e?) and its application towards the development of redox catalysisviaswitching with the mono-reduced form (13π e?) for aryl halide activation and functionalization under transition metal free conditions without any external stimuli such as heat, light or cathodic current supply.
