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N. N. Chipanina G. N. Sarapulova D. A. Bravo-Zhivotovskii S. D. Pigarev O. A. Byazankina Yu. I. Frolov N. S. Vyazankin 《Russian Chemical Bulletin》1984,33(2):310-313
Conclusions The values of C=0 in the IR spectra and the position of the band from the n * electronic transition in the UV spectra of the amides R1CONR2R3 vary linearly with the inductive effect of the R1 substituent (for R2=R3=H, Alk). This may indicate the absence of the intramolecular coordination Ge 0, where or. The substituent R1=Ge(C2H5)2 exhibits electron-acceptor properties besides a +I-effect.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 349–352, February, 1984. 相似文献
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Y. Apeloig D. Bravo-Zhivotovskii M. Yuzefovich M. Bendikov A. I. Shames 《Applied magnetic resonance》2000,18(3):425-434
Electron paramagnetic resonance (EPR) spectroscopy was fruitfully used for studying the formation and the reactions of the star polysilane radical (Me3SiMe2Si)3Si (1).1, which was successfully generated both thermally and photochemically from a variety of precursors, was found to be significantly more stable kinetically than the (Me3Si)3Si radical. Thus, (Me3SiMe2Si)3Si⋅ has a half-life time of ca. 6 min at 20°C, while (Me3Si)3Si⋅ can be observed only at −25°C. Density-functional quantum-mechanical calculations show that1 and (Me3Si)3Si⋅ have the same thermodynamic stability. The high kinetic stability of1 is attributed to its backfold “umbrella”-type conformation where the β-silyl groups point “inwards” towards the radical center. This conformation protects the radical center of1 from dimerization and other reactions. The EPR spectrum of1 and in particular the Si α-hyperfine coupling constant of 5.99 mT shows that1 is less pyramidal than (Me3Si)3Si⋅ but is more pyramidal than (i-Pr3Si)3Si⋅, with an estimated SiSiSi bond angle around the radical center of 118∘. Photolysis and thermolysis of [(Me3SiMe2Si)3Si]2 also involves the intermediacy of1. Photolysis of [(Me3SiMe2Si)3Si]2 leads to (Me3SiMe2Si)4Si, while thermolysis produced the less strained isomer of 1, (Me3SiMe2Si)3SiSi-Me2Si(Me3SiMe2Si)2SiMe3. In this study we provide the first direct evidence that silyl radicals are involved as intermediates in the reactions of silanes with di(tert-butyl)mercury. 相似文献
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Mashin Eivgeni Kratish Yosi Kaushansky Alexander Bravo-Zhivotovskii Dmitry Apeloig Yitzhak 《Structural chemistry》2017,28(2):537-544
Structural Chemistry - The synthesis and the X-ray structural analysis of novel pincer and half-pincer silyllithiums: Ar2 (N)(tBu2MeSi)SiLi (Ar(N) = o-dimethylbenzylamine) (2a),... 相似文献
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D. A. Bravo-Zhivotovskii T. I. Vakul'skaya I. S. Biltueva N. S. Vyazankin M. G. Voronkov 《Russian Chemical Bulletin》1989,38(6):1334-1334
Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, p. 1453, June, 1989. 相似文献
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D. A. Bravo-Zhivotovskii S. D. Pigarev O. A. Vyazankina A. S. Medvedeva L. P. Safronova N. S. Vyazankin 《Russian Chemical Bulletin》1984,33(8):1733-1734
Conclusions The reaction of Et3GeLi with N,N-dialkylamides of trimethylsilylpropiolic acid led under conditions of kinetic control to triethyl(trimethylsilylpropiolyl)germane and under conditions of thermodynamic control to the corresponding amide of triethylgermylcarboxylic acid.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1897–1898, August, 1984. 相似文献
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