Synthesis, Structure, and Functions of Low-Valent Organosilicon, -germanium, and -tin Compounds

本文研究了硅离子、硅烯等低价有机硅化合物及其相关锗、锡化合物的合成、分离、结构和反应，以期发现这些化合物的独特功能。(1)在77K条件下，从3-MP和2-MeTHF基质中光解相应的三硅烷中首次分离到乙烯基硅烯和三烷基硅基硅烯。与理论预测相反，乙烯基取代引起了二甲基硅烯n(Sl)-3p（SI）跃迁的显著红移。水仙花在超长波长处表现出极大的跃迁带，表明存在较小的S-T分裂。(2)合成了2,2,5,5 -四基斯（三甲基硅基）锡环戊烷- 1,1 -二基(1)，并通过核磁共振、高分辨率质量、紫外可见光谱和x射线晶体学对其进行了表征，作为固体和溶液中第一个配位数为2的单体二基锡炔，与结构相似的bls[双（三甲基）基]锡炔(2)形成对比。它在溶液中是单体，但在固态中是二聚体。新设计的环状配体In 1比两个bls（三甲基基）甲基取代基In 2更有效地保护二价tln原子免受二聚化。(3)硅烷与三烷基四[3,5 -二（三氟甲基）苯基]硼酸盐（TFPB）在过量醚存在的二氯甲烷-d_2中反应时，用^1H， ^<13>C和^<29>Si核磁共振观察到硅离子的第一醚配合物在低温下为长能态，而在没有任何碱的情况下不产生三价硅离子。使用TFPB作为非亲核反阴离子是成功观察配合物的关键；在相同条件下生成的高氯酸盐与醚的相互作用不明显。通过对（3-乙氧基丙基）四甲基硅烷与三甲基TFPB反应的NYIR监测，得到了硅离子与烷氧基氧的分子内络合的明确证据。少

Synthesis, isolation, structure, and reactions of low-valent organosilicon compounds such as silicenium Ions and silylenes, and related germanium and tin compounds were investigated In order to discover the unique functions of these species. Following remarkable results were obtained :(1)The first vinylsilylenes and trlalkylsilylsilylenes were Isolated from photolysis of the corresponding trisilanes In 3-MP and 2-MeTHF matrices at 77K. Contrary to the theoretical predictions, vinyl substitution caused a significant red shift of the n(Sl)-3p(SI)transition of dimethylsilylene. Silylsllylelnes showed the transition band maxima at unusually long wavelength, suggesting the small S-T splitting.(2)A dialkylstannylene, 2, 2, 5, 5-tetrakis(trimethylsilyl)stannacyclopentane-l, l-diyl(1)was synthesized and characterized with NMR, high resolution mass, and UV-VIS spectroscopy, and X-ray crystallography, as the first monomeric dialkylstannylene with the coordination number of two In the solid state … More as well as In solution, In contrast to the structurally similar bls[bis(trimethylsllyl)methyl]stannylene(2), which Is known to be monomeric in solution but dimeric In the solid state. The newly designed cyclic ligand In 1 sterically protects the divalent tln atom from dimerization more effectively than two bls(trimethylsllyl)methyl substituents In 2.(3)The first ether complexes of silicenium Ions were observed as long-Hved species at low temperatures by ^1H, ^<13>C, and ^<29>Si NMR during the reactions of silanes with trityl tetrakis[3, 5-bis(trifluoromethyl)phenyl]borate(TFPB)In dichloromethane-d_2 in the presence of excess ethers, while trivalent silicentum Ions were not produced In the absence of any bases. The use of TFPB as a non-nucleophilic counter anion was crucial for the successful observation of the complexes ; sllyl perchlorates formed under the similar conditlons did not show significant Interaction with ethers. Clear evidence for the Intramolecular complexation of silicenlum Ions with alkoxy oxygens was obtained by monitoring the reaction of(3-ethoxypropyl)dlmethylsilane with trityl TFPB by NYIR. Less