Electrochemical Oxidation and Radical Cations of Structurally Non-rigid Hypervalent Silatranes: Theoretical and Experimental Studies

详细信息    查看全文

• 作者：Prof. Valery F. Sidorkin ; Dr. Elena F. Belogolova ; Dr. Yu Wang ; Prof. Viatcheslav Jouikov and Dr. Evgeniya P. Doronina
• 刊名：Chemistry - A European Journal
• 出版年：2017
• 出版时间：February 3, 2017
• 年：2017
• 卷：23
• 期：8
• 页码：1910-1919
• 全文大小：1203K
• ISSN：1521-3765

文摘

Using 18 silatranes XSi(OCH₂CH₂)₃N (1) as examples, the potentials of electrochemical oxidation Ep>0p> of the hypervalent compounds of Si were calculated for the first time at the ab initio and DFT levels. The experimental peak potentials E_p (acetonitrile) show an excellent agreement (MAE=0.03) with the MP2//B3PW91 calculated Ep>0p> (C-PCM). Radical cations of 1 reveal a stretch isomerism of the N→Si dative bond. Localization of the spin density (SD) on the substituent X and the short (s) coordination contact Si⋅⋅⋅N (d_SiN<2.13 Å) along with the high five-coordinate character of Si are typical for the first isomer 1p>+.(s)p>, whereas the second one, 1p>+.(l)p>, has a longer (l) Si⋅⋅⋅N distance (d_SiN>3.0 Å), the four-coordinate Si and the SD localized on the silatrane nitrogen atom N_s. The vertical model of adiabatic ionization (1→1p>+.(s)p> or 1→1p>+.(l)p>) was developed. It allows, in accordance with an original experimental test (electrooxidation of 1 in the presence of ferrocene), a reliable prediction of the most probable pathways of the silatrane oxidation. The reliable relationships of Ep>0p>(1) with the strength characteristics of the dative contact N→Si were revealed.