4‐Alkyl‐2,2,6,6‐tetramethyl‐1,4,2,6‐oxaazadisilinanes: synthesis,structure, and conformational analysis |
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| Authors: | Nataliya F. Lazareva Bagrat A. Shainyan Erich Kleinpeter |
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| Affiliation: | 1. A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Division of the Russian Academy of Science, 1 Favorsky Street, 664033 Irkutsk, Russian Federation;2. Chemisches Institut der Universitat Potsdam, D‐14415 Potsdam, Germany |
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| Abstract: | 4‐Alkyl‐2,2,6,6‐tetramethyl‐1,4,2,6‐oxaazadisilinanes RN[CH2Si(Me)2]2O [R = Me ( 1 ), i‐Pr ( 2 )] were synthesized by two methods which provided good yields up to 84%. Low temperature NMR study of compounds ( 1 ) and ( 2 ) revealed a frozen ring inversion with the energy barriers of 8.5 and 7.7 kcal/mol at 163 and 143 K, respectively, which is substantially lower than that for their carbon analog, N‐methylmorpholine. DFT calculations performed on the example of molecule ( 1 ) showed that N? Meax conformer to exist in the sofa conformation with the coplanar fragment C? Si? O? Si? C, and its N? Meeq conformer in a flattened chair conformation. Copyright © 2009 John Wiley & Sons, Ltd. |
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| Keywords: | 4‐alkyl‐1,4,2,6‐oxaazadisilinanes conformational analysis dynamic NMR NBO analysis quantum chemical calculations |
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