- Triphenylamine, carbazole or tetraphenylethylene-based gold(I) complexes: Tunable solid-state room-temperature phosphorescence and various mechanochromic luminescence characteristics
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Three novel gold(I) complexes based on triphenylamine, carbazole or tetraphenylethylene moiety have been successfully designed and synthesized. Meanwhile, their structures were characterized by nuclear magnetic resonance spectroscopy and elemental analysis. Their solid-state luminescence characteristics were surveyed by photoluminescence spectroscopy, and their distinct mechanical stimulus-responsive behaviors in the solid state were also investigated by photoluminescence spectroscopy. Interestingly, the solid-state phosphorescence and emission lifetimes of these mononuclear gold(I) complexes 1–3 could be tuned by introducing different fluorophores involving triphenylamine, carbazole or tetraphenylethylene. Furthermore, luminogen 1 exhibited switchable mechanochromic luminescence behavior with color change from yellow to colorless, and the solid-state luminescence on-off mechanochromism between yellow-green and colorless of luminogen 2 could also be observed. However, no mechanochromism phenomenon was observed for tetraphenylethene-containing luminogen 3. The powder X-ray diffraction results suggested that the unusual high-contrast mechanochromism characteristics of luminogens 1 and 2 could be attributed to a crystalline-to- amorphous morphology transition.
- Chen, Zhao,Liu, Gang,Pu, Shouzhi,Liu, Sheng Hua
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- Tetracoordinate borates as catalysts for reductive formylation of amines with carbon dioxide
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We report sodium trihydroxyaryl borates as the first robust tetracoordinate organoboron catalysts for reductive functionalization of CO2. These catalysts, easily synthesized from condensing boronic acids with metal hydroxides, activate main group element-hydrogen (E-H) bonds efficiently. In contrast to BX3 type boranes, boronic acids and metal-BAr4 salts, under transition metal-free conditions, sodium trihydroxyaryl borates exhibit high reactivity of reductive N-formylation toward a variety of amines (106 examples), including those with functional groups such as ester, olefin, hydroxyl, cyano, nitro, halogen, MeS-, ether groups, etc. The over-performance to catalyze formylation of challenging pyridyl amines affords a promising alternative method to the use of traditional formylation reagents. Mechanistic investigation supports electrostatic interactions as the key for Si/B-H activation, enabling alkali metal borates as versatile catalysts for hydroborylation, hydrosilylation, and reductive formylation/methylation of CO2.
- Du, Chen-Xia,Huang, Zijun,Jiang, Xiaolin,Li, Yuehui,Makha, Mohamed,Wang, Fang,Zhao, Dongmei
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supporting information
p. 5317 - 5324
(2020/09/17)
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- CuSO4-Catalyzed Tandem C(sp3)-H Insertion Cyclization of Toluenes with Isonitriles to Form Indoles
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A CuSO4-catalyzed tandem benzylic C-H insertion cyclization of toluene derivatives and isonitriles is described. The naturally abundant salt CuSO4 serves as a low-cost ligand-free redox catalyst. This reaction provides a practical mo
- Shan, Xiang-Huan,Wang, Mei-Mei,Tie, Lin,Qu, Jian-Ping,Kang, Yan-Biao
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supporting information
p. 357 - 360
(2020/01/31)
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