Cationic Clusters Consisting of Heavier Group 14 Elements

研究了14族重元素中稳定离子的化学性质，包括正离子、阴离子和自由基。通过实验和计算研究，研究了这些离子在固态和溶液中的电子和晶体结构特征。高度密集的3,3-二（二叔丁基甲基硅1）-1,2-二（三叔丁基硅基）环三硅烯是一种具有Si=Si键的不饱和三元化合物，用四芳基硼酸三苯基甲基处理得到（二叔丁基甲基硅基）二（三叔丁基硅基）环三硅基离子，这是环丙烯离子的第一个可分离的硅同系物。x射线晶体结构和光谱数据表明，环三硅离子不仅是一个自由的硅基阳离子，而且是一个具有正电荷离域的2a电子芳族物质。用石墨钾还原脱卤法制备了重环丁二烯二离子四（二叔丁基甲基硅氧烷）-1,2-二硅氧烷-3,4-二聚环丁二烯二离子和四（二叔丁基甲基硅氧烷）四硅基丁二烯二离子。根据环丁二烯离子的结构特点和不存在各向异性环电流效应，发现其为非芳香族。三[二叔丁基（甲基）硅基]硅基和germyl阴离子与二氯二甲二氧环配合物的单电子氧化反应生成了稳定的三[二叔丁基（甲基）硅基]硅基和germyl自由基。硅基自由基和根霉基自由基的晶体结构均表现为围绕自由基中心的完全平面几何结构。EPR谱显示了两个自由基的a-特征，对应于自由基中心的平面几何和sp2杂化。

The chemistry of the stable ionic species of heavier group 14 elements has been studied, including both cationic and anionic species together with radical species. The electronic and crystal structural features of these ionic species, both in the solid state and in solution, have been investigated by the experimental and computational study.1. The highly crowded 3,3-bis(di-tert-butylmethylsily1)-1,2-bis(tri-tert-butylsilyl)cyclotrisilene, an unsaturated three-membered compound with an Si=Si bond, was treated with triphenylmethylium tetraarylborate to produce (di-tert-butylmethylsilyl)bis(tri-tert-butylsilyl)cyclotrisilenylium ion, representing the first isolable silicon congener of the cyclopropenylium ion. The X-ray crystal structure and spectral data show that the cyclotrisilenylium ion is not only a free silyl cation but also a 2a electron aromatic species with delocalization of the positive charge over the three-membered skeleton.2. The heavy cyclobutadiene dianions, tetrakis(di-tert-butylmethylsily1)-1,2-disila-3,4-digermacyclobutadiene dianion and tetrakis(di-tert-butylmethylsilyl)tetrasilacyclobutadiene dianion, have been synthesized by the reductive dehalogenation of the corresponding precursors with potassium graphite. The cyclobutadiene dianions were found to be nonaromatic by their structural features and the lack of diatropic ring current effects.3. The one-electron oxidation reaction of tris[di-tert-butyl(methyl)silyl]silyl and germyl anions with dichlorogermylene dioxane complex resulted in the formation of stable tris[di-tert-butyl(methypsilyl]sily1 and germyl radicals. The crystal structures of both silyl and germyl radicals showed a completely planar geometry around the radical centers. The EPR spectra indicate the a-character of both radicals, corresponding to a planar geometry and sp2 hybridization of the radical centers.