| Research Abstract |
The aim of our study has been to synthesize novel stable group-14 element unsaturated compounds and to reveal their structure and reactions.
The following are the major results: (1) Unusual reactions of stable dialkylsilylene with dichloromethane and chloromethylcyclopropane were discovered. The results were explained by invoking the ambiphilic nature of silylene. (2) The reactions of the electronically excited silylene with benzene derivatives were first observed. The excited silylene should have the nature of the singlet 1,1-biradical. (3) An apparent discrepancy for the dimer structure of bis(diisopropyl-amino)silylene between experiment and theory was solved by the detailed theoretical study. (4) Rates and mechanism of the E,Z-isomerization in tetrakis(trialkylsilyl)disilenes were revealed. (5) Unique mechanisms of the reactions of disilenes with alcohols and chloroalkanes were proposed on the basis of the theoretical and experimental studies. (6) A new silyllithium reagent, a 1,2-d
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ilithiodisilane (1), was prepared by the reaction of a tetrakis(trialkylsilyl)disilene with lithium in THF. (7) A 1,3-disilabicyclo[1.1.0]butane was synthesized using the reaction of the 1,2-dilithio-disilane 1 with a ketone. The disilabicyclobutane was found to have a unique inverted σ bridge bond. (8) A disilene-platinum complex, which has a metallacyclopropane type structure, was synthesized using the reaction of 1 with a dichloroplatinum and its structure was determined by X-ray crystallography. (9) A silicon-bowtie compound (spiropentasiladiene), whose carbon analogs have never been isolated, was first synthesized. The unique spiro-conjugation in the molecule was revealed by X-ray crystallography and theoretical calculations. (10) A stable 4-silatriafulvene having an Si=C bond with inverted polarity was synthesized and characterized by X-ray crystallography and various spectroscopies.
All these results will contribute to construct a new concepts of structure and bonding in the chemistry of main-group elements and to offer the basic structures for the future functional materials. Less
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