- 作者: 王瑜 ; 王志傑
- 作者服務機構: 台灣大學化學系
- 中文摘要: 1,3,5,7-Tetra-t-butyl-s-indacene is a twelve-membered fused-ring compound; the stabilization of the compound by bulky t-butyl groups is discussed. The distribution of bonding electron density is depicted in terms of deformation density using the experimental X-X method, a multipole expansion model and a calculation according to the extended Huckel molecular orbital method (EHMO). The molecules crystallize according to the space group P2/sub 1//n with cell parameters a=9.700(3), b=11.746(3), c=10,858(2).ANG.,.beta.=107.67(2).degree., Z=2 at 100K. The molecule has a center of inversion(.1bar.) and belongs to the symmetry point group C/sub i/. The packing of two unique t-butyl gropus in the asymmetric unit appears significantly different. However, the map of deformation density in the plane of the ring shows pseudo D/sub 2h/ symmetry. The accumulation of density at the midpoint of the the bonds is observed as expected. The theoretical deformation densities agree with the experimental ones. Analyses of the molecular-orbital wavefunctions provide a good illustration of the aromatic .pi.-electron system. A theoretical study of a series of substituents (-H, -CH/sub 3/, -t-butyl) on s-indacene illustrates the stabilization effect of the t-butyl group on the 12-.pi.-electron ring system.
- 英文摘要: --
- 中文關鍵字: Deformation Density Distribution; Electron Density Distribution; S-Indacene; Huckel Molecular Orbital Method; 1,3,5,7-Tetra-T-Butyl-S-Indacene
- 英文關鍵字: 變形密度分布;電子密度分布;Huckel分子軌域法