The Donor-Stabilized Silylene Bis[N,N′-diisopropylbenzamidinato(-)] silicon(II): Synthesis, Electronic Structure, and Reactivity
The Donor-Stabilized Silylene Bis[N,N′-diisopropylbenzamidinato(-)] silicon(II): Synthesis, Electronic Structure, and Reactivity
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DOI：
10.1002/chem.201402483
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发表时间：
2014-07-21
影响因子：
4.3
通讯作者：
Tacke, Reinhold
中科院分区：
文献类型：
--
作者：
Junold, Konstantin;Nutz, Marco;Tacke, Reinhold
已经开发了一种方便和稳健的合成双[N，N '-二异丙基苯甲脒（-）]硅（II）（1），一种供体稳定的亚硅烷基（35 g规模）。为了得到关于1的反应性特征的进一步信息，研究了一系列氧化加成反应。用PhSe-SePh（Se-Se键活化）、C6 F6（C-F活化）和CO2（C=O活化/环加成）处理1分别产生中性六配位硅（IV）配合物10、11和13。用N2 O处理1导致形成双核五配位硅（IV）配合物12（氧化加成/二聚），其含有四元Si 2 O2环。化合物10-13通过固态和溶液中的NMR光谱研究以及通过晶体结构分析来表征。甲硅烯1在固态下是三配位的（来自晶体结构分析），并且在苯溶液中以四配位异构体1'存在（来自计算研究）。基于最先进的相对论DFT分析，四配位物种1'被证明是苯溶液中的热力学上有利的异构体（相对于三配位物种1有利的Δ G=6.6 kcal mol（-1））。通过1和1 '的成键分析研究了其原因。计算了1和1'的~（29）Si NMR化学位移，并分析了溶剂化对1' NMR谱参数的影响。这些研究进一步支持了硅烯在溶液中是四配位的假设。
A convenient and robust synthesis of bis[N, N'-di-isopropylbenzamidinato(-)] silicon(II) (1), a donor-stabilized silylene, has been developed (35 g scale). To get further information about the reactivity profile of 1, a series of oxidative addition reactions were studied. Treatment of 1 with PhSe-SePh (Se-Se bond activation), C6F6 (C-F activation), and CO2 (C=O activation/cycloaddition) yielded the neutral six-coordinate silicon(IV) complexes 10, 11, and 13, respectively. Treatment of 1 with N2O resulted in the formation of the dinuclear five-coordinate silicon(IV) complex 12 (oxidative addition/dimerization), which contains a four-membered Si2O2 ring. Compounds 10-13 were characterized by NMR spectroscopic studies in the solid state and in solution and by crystal structure analyses. Silylene 1 is three-coordinate in the solid state (from crystal structure analysis) and exists as the four-coordinate isomer 1' in benzene solution (from computational studies). Based on state-of-the-art relativistic DFT analyses, the four-coordinate species 1' was demonstrated to be the thermodynamically favored isomer in benzene solution (favored by Delta G=6.6 kcal mol(-1) over the three-coordinate species 1). The reason for this was studied by bonding analyses of 1 and 1'. Furthermore, the 29Si NMR chemical shifts of 1 and 1' were computed, and in the case of 1' it was analyzed how this NMR spectroscopic parameter is affected by solvation. These studies further supported the assumption that the silylene is four-coordinate in solution.