Tetrahedrane and Cyclobutadiene: Synthesis and Structure of Highly Strained Hydrocarbons

四面烷是一种碳氢化合物，具有高度应变的C-C西格玛键。由于骨架的高度应变，C-C sigma键轨道能级的增加导致了sigma-pi共轭。环丁二烯是四面体的价异构体之一，是一个矩形平面四元环上含有四个pi电子的环状不饱和化合物。我们研究了硅基稳定取代四面体的合成、结构分析和性质。全氟芳基取代的环丁二烯衍生物通过相应的四面体的光化学异构化反应制备了对空气和湿气敏感的红色固体。第一个芳基取代的环丁二烯通过光谱数据和X射线结晶学进行了表征。我们还开发了多种取代四面体的合成路线，到目前为止已经报道了20多个稳定的衍生物。

Tetrahedrane is a hydrocarbon with highly strained C-C sigma bonds. Because of the extremely strained skeleton, the increase in the energy level of C-C sigma-bond orbitals results in the sigma-pi conjugation. Cyclobutadiene is one of valence isomers of tetrahedrane and a cyclic unsaturated compound with four pi-electrons within a rectangular planar four-membered ring.We have investigated the synthesis, structural analysis and properties of substituted tetrahedranes stabilized by silyl groups. The perfluoroaryl substituted cyclobutadiene derivatives were prepared as air- and moisture-sensitive red solids by the photochemical isomerization of the corresponding tetrahedranes. The first aryl substituted cyclobutadienes were characterized by spectroscopic data as well as by Xray crystallography. We also developed new versatile synthetic routes of substituted tetrahedranes, and reported more than 20 stable derivatives up to now.