- First cycloruthenation of 2-alkenylpyridines: synthesis, characterization and properties
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Several cyclometalated ruthenium complexes 1-5 with 2-alkenylpyridines as C,N-chelating ligands were synthesized and then characterized by NMR, MS, IR and UV-Vis spectra. According to the single crystal of complex 2, it is evident that carbon from vinyl group is successfully bonded to Ru(ii) center. Moreover, the Ru-N bond trans to the Ru-C bond is elongated (2.127(5) ?), which is consistent with the strong trans effect of the carbon atom compared to that of the nitrogen atom. With different electron-donating groups linked to vinyl, these complexes exhibited regular changes in MLCT absorption bands, which were identified by UV-Vis and CV spectra in combination with DFT and TD-DFT. Interestingly, protonated intermediate species of these complexes in acidic solutions were tracked by the absorption changes and MS spectra, which displayed a possible protonation process of these complexes with the cleavage of Ru-C σ bonds.
- Wu, Yuhao,Su, Xianlong,Xie, Chaoyi,Hu, Rongrong,Li, Xianghong,Zhao, Qiang,Zheng, Guoli,Yan, Junkun
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p. 4138 - 4146
(2021/02/02)
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- Excited-state proton transfer and excited-state de-hydrogen bonding of the push-pull styryl system
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The excited-state reaction of push-pull styryl system was studied in this work. In the excited state, compounds of 2-StP-NMe2, 2-StQ-NMe 2, 4-StQ-NMe2 and 4-StP-NMe2 possess a sufficiently large acidity change f
- Wang, Shun-Li,Gao, Guo-Yi,Ho, Tong-Ing,Yang, Li-Yu
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p. 217 - 222
(2007/10/03)
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- Photocatalyzed [2 + 2 + 2]-cycloaddition of nitriles with acetylene: An effective method for the synthesis of 2-pyridines under mild conditions
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The photocatalyzed [2 + 2 + 2]-cycloaddition of nitriles with 2 equiv of acetylene to 2-pyridines can be carried out under mild conditions and represents a valuable extension to common synthetical methods. For the ideal wavelength range (350-500 nm), lamps as well as sunlight can be used. Working at room temperature and in organic solvents such as toluene or hexane as well as in water gives satisfying results in many cases. However, it is also possible to vary the solvent and the reaction temperature of the photocatalyzed synthesis and to choose, with respect to the specific substrate, specific requirements for this particular reaction and general requirements of the method. This simple and selective method derives its potential mainly from the large variety of applicable nitriles. Suitable substrates include (functionalized) aliphatic and aromatic nitriles as well as cyanamides derived from secondary amines.
- Heller, Barbara,Sundermann, Bernd,Buschmann, Helmut,Drexler, Hans-Joachim,You, Jingsong,Holzgrabe, Ulrike,Heller, Eberhard,Oehme, Guenther
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p. 4414 - 4422
(2007/10/03)
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- CHARACTERISTIC FEATURES OF THE CONDENSATION OF PICOLINE BORON TRIFLUORIDE COMPLEXES WITH AROMATIC ALDEHYDES
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The formation of complexes 2- and 4-picolines with BF3 results in a significant activation of their methyl groups.This makes it possible to carry out condensations with aromatic aldehydes under mild conditions.The reaction of 2-picoline with 4-(dimethylamino)benzaldehyde in acetic anhydride solution results in the splitting of the pyridine ring with formation of an unstable product.
- Vasil'ev, A. N.,Mushkalo, L. K.
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p. 1718 - 1720
(2007/10/02)
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