Polyhedral Silicon and Germanium Compounds

多面体碳化合物，如四面体、棱柱烷和立方烷，由于其高度的对称性而具有独特的性质和美感，长期以来一直吸引着化学家。为了丰富14族元素的化学性质，硅和锗类似物的合成是一个巨大的挑战，因为它可能导致碳化合物意想不到的新的物理和化学性质。然而，直到最近，这样的合成一直被认为是不可能的。该项目成功地合成、分离和表征了多面体硅和锗化合物，如六硅丙烷、六硅丙烷、八硅立方烷和八面体马卡巴。研究结果如下：1)八硅立方烷和八角杂立方烷的合成与表征；2)八硅立方烷和八角杂立方烷的结构测定；3)六硅立方烷和六硅立方烷的合成与表征；4)六硅立方烷和六硅立方烷的结构测定；5)UV-Vis光谱和固体核磁共振光谱测定物性。事实上，当在340-380 nm波长的光下在溶液中低温照射时，六硅丙烷和六硅丙烷提供了相应的杜瓦苯衍生物。

Polyhedral carbon compounds such as tetrahedrane, prismane, and cubane have long fascinated chemists because of the unique properties and aesthetic appeal due to high symmetry. In an effort to enrich group 14 element chemisty, synthesis of the silicon and germanium analogues is a great challenge since it could lead to novel physical and chemical properties unexpected from the carbon compounds. However, such synthesis was thought to be impossible until recently. The successful syntheses, isolation, and characterization of polyhedral silicon and germanium compounds such as hexasilaprismane, hexagermaprismane, octasilacubane, and octagermacubane have been performed by this project. The research results are as follows.1) Synthesis and characterization of octasilacubane and octagermacubane.2) Structural determination of octasilacubane and octagermacubane by the X-ray crystallography.3) Synthesis and characterization of hexasilaprismane and hexagermaprismane.4) Stuctural determination of hexasilaprismane and hexagermaprismane by the X-ray crystallography.5) Physical properties by UV-Vis spectra and solid state NMR spectra.Prismanes are valence isomers of benzene, Dewar benzene, benzvalene. Indeed, the hexasilaprismane and hexagermaprismane afforded the corresponding Dewar benzene derivatives upon irradiation in solution at low temperature with light having wavelengths of 340-380 nm.