TOKITOH Norihiro The University of Tokyo, Graduate School of Science, Research Associate, 大学院・理学系研究科, 助手 (90197864)
KAWASHIMA Takayuki The University of Tokyo, Graduate School of Science, Associate Professor, 大学院・理学系研究科, 助教授 (80011766)
|Budget Amount *help
¥36,600,000 (Direct Cost : ¥36,600,000)
Fiscal Year 1993 : ¥7,600,000 (Direct Cost : ¥7,600,000)
Fiscal Year 1992 : ¥29,000,000 (Direct Cost : ¥29,000,000)
In this study the following three projects were carried out. (1) Synthesis of stable silicenium ions and their reactivities. (2) Synthesis and reactivities of penta-coordinate oxaphosphetanes and oxasiletanides. (3) Synthesis and reactivities of double-bond compounds between group 14 and group 16 elements.
(1) Synthesis of silicenium ions (ArX)_3Si^+(X=S, Se ; Ar=2,4,6-tri-t-butylphenyl) and mes_3Si^+ was carried out by the reaction of (ArX)_3SiCl with AgClo_4 and that of Mes_3 SiCl with SbCl_5. Both reactions gave products explicable in terms of the intermediary of silicenium ions, but they could not be isolated.
(2) Penta-coordinate oxaphosphetanes and oxasiletanides, intermediates of the Wittig and Peterson reactions, respectively, were synthesized by taking advantage of the Martin ligand C_6H_5(CF_3)_2(OH) which is known to stabilize high-coordinate compounds, and their structures were established by X-ray crystallography. An study on their thermolyses revealed the mechanism of the Wittig and Peterson reactions.
(3) Synthesis of compounds having a double bond between heavy group 14 and group 16 elements (heavy congeners of a ketone), TbArM=X(M=Si, Ge, Sn ; Tb=2,4,6-tris[bis(trimethylsilyl)methyl] phenyl ; Ar=mesityl or 2,4,6-triisopropylphenyl(Tip)) was studied. The first stable germanethione, Tb(Tip) Ge=S, was isolated and its structure was established by X-ray crystallography. It underwent various additions and cycloadditions oward the very reactive Ge=S bond.