Lebedev Yury N, Das Ujjal, Chernov Oleg, Schnakenburg Gregor, Filippou Alexander C
Institut für Anorganische Chemie, Universität Bonn, Gerhard-Domagk-Straße 1, 53121 Bonn (Germany).
Chemistry. 2014 Jul 21;20(30):9280-9. doi: 10.1002/chem.201403108. Epub 2014 Jun 17.
A novel method for the synthesis of 1H-siloles is presented. It involves a [2+2+1] cycloaddition of the ynediamines R2N-C≡C-NR2 (R = Me, Et) with SiI2(Idip) (Idip = 1,3-bis(2,6-diisopropylphenyl)imidazolin-2-ylidene) to afford the orange-colored, highly water-sensitive 1,1-diiodo-2,3,4,5-tetraamino-1H-siloles SiI2{C4(NR2)4} (1-I: R = Me; 2-I R = Et). Treatment of 2-I with an excess of SiBr4 afforded after I/Br exchange the 1,1-dibromo-1H-silole SiBr2{C4(NEt2)4} (2-Br). The 1H-siloles 1-I, 2-I, and 2-Br were fully characterized and their molecular structures determined by single-crystal X-ray diffraction. The compounds feature a slightly twisted five-membered silacyclopenta-2,4-diene ring and a double/single C-C bond alternation in the diene fragment. Reaction of 2-I with the N-heterocyclic carbene IMe4 (IMe4 = 1,3,4,5-tetramethylimidazolin-2-ylidene) leads, after displacement of the iodide groups, to the unprecedented diiodide salt Si(IMe4)2{C4(NEt2)4}2 (3), containing a 1H-silole dication with a four-coordinate Si(IV) center. The crystal structure of 3 reveals similar bonding characteristics for the dicationic 1H-silole to those of the neutral 1H-siloles 1-I-2-Br. Two-electron reduction of 3 with C8K affords, after elimination of one IMe4 group, the thermolabile, carbene-stabilized 1-silacyclopentadien-1-ylidene Si{C4(NEt2)4}(IMe4) (4), which was characterized by elemental analysis and (1)H, (13)C{(1)H}, and (29)Si{(1)H} NMR spectroscopies.
本文介绍了一种合成1H-硅杂环戊二烯的新方法。该方法涉及炔二胺R2N-C≡C-NR2（R = 甲基、乙基）与SiI2(Idip)（Idip = 1,3-双(2,6-二异丙基苯基)咪唑啉-2-亚基）进行[2+2+1]环加成反应，得到橙色、对水高度敏感的1,1-二碘-2,3,4,5-四氨基-1H-硅杂环戊二烯SiI2{C4(NR2)4}（1-I：R = 甲基；2-I：R = 乙基）。用过量的SiBr4处理2-I，经碘/溴交换后得到1,1-二溴-1H-硅杂环戊二烯SiBr2{C4(NEt2)4}（2-Br）。对1H-硅杂环戊二烯1-I、2-I和2-Br进行了全面表征，并通过单晶X射线衍射确定了它们的分子结构。这些化合物具有一个略微扭曲的五元硅杂环戊-2,4-二烯环，并且在二烯片段中存在碳-碳双键/单键交替。2-I与N-杂环卡宾IMe4（IMe4 = 1,3,4,5-四甲基咪唑啉-2-亚基）反应，在碘基团被取代后，生成了前所未有的二碘盐Si(IMe4)2{C4(NEt2)4}2（3），其中含有一个具有四配位Si(IV)中心的1H-硅杂环戊二烯二价阳离子。3的晶体结构表明，二价阳离子1H-硅杂环戊二烯的键合特征与中性1H-硅杂环戊二烯1-I - 2-Br的相似。用C8K对3进行双电子还原，在消除一个IMe4基团后，得到热不稳定的、由卡宾稳定的1-硅杂环戊二烯-1-亚基Si{C4(NEt2)4}(IMe4)（4），通过元素分析以及1H、13C{1H}和29Si{1H}核磁共振光谱对其进行了表征。
