• Title/Summary/Keyword: Silyl($SiH_3$)

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Interaction of Hydrosilanes with the Surface of Rhodium

  • Boo Bong Hyun;Hong Seung Ki;Lee Sun Sook;Kim Hyun Sook
    • Bulletin of the Korean Chemical Society
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    • v.15 no.12
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    • pp.1103-1107
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    • 1994
  • Interaction of triethylsilane and diphenylsilane ($Ph_2$$SiH_2$, $Ph_2$$SiD_2$) with the surfaces of rhodium has been examined by trapping the reaction intermediates with 2,3-dimethyl-l,3-butadiene. 1,4-Hydrosilylation of the diene is predominantly observed to occur under mild condition over the rhodium catalyst. It is inferred from the product analyses that silylene and silyl radicals bonded to rhodium surfaces are the intermediates for addition of silylene to the diene, and for 1,4-hydrosilylation, respectively.

Dehydrocoupling of Bis(silyl)alkylbenzenes to Network Polysilanes, Catalyzed by Group 4 Metallocene Combination

  • Kim, Myoung-Hee;Lee, Jun;Moo, Soo-Yong;Kim, Jong-Hyun;Ko, Young Chun;Woo, Hee-Gweon
    • Journal of Integrative Natural Science
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    • v.3 no.1
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    • pp.1-6
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    • 2010
  • Bis(silyl)alkylbenzenes such as bis(1-sila-sec-butyl)benzene (1) and 2-phenyl-1,3-disilapropane (2) were synthesized in high yields by the reduction of the corresponding chlorosilanes with $LiAlH_4$ in diethyl ether. The dehydrocoupling of 1 and 2 was performed using group IV metallocene complexes generated in situ from $Cp_2MCl_2$/Red-Al and $Cp_2MCl_2$/n-BuLi (M = Ti, Hf), producing two phases of polymers. The TGA residue yields of the insoluble polymers were in the range of 64-74%. The molecular weights of the soluble polymers produced ranged from 700 to 5000 ($M_w$ vs polystyrene using GPC) and from 500 to 900 ($M_w$ vs polystyrene using GPC). The dehydropolymerization of 1 and 2 seemed to initially produce a low-molecular-weight polymer, which then underwent an extensive cross-linking reaction of backbone Si-H bonds, leading to an insoluble network polymer.

Photopolymerization of Methyl Methacrylate with Primarty Aryl- and Alkylsilanes

  • 우희권;홍란영;양수연;박선희;송선정;함희석
    • Bulletin of the Korean Chemical Society
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    • v.16 no.11
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    • pp.1056-1059
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    • 1995
  • The bulk photopolymerization of methyl methacrylate (MMA) with primary arylsilane (e.g., phenylsilane) and various primary alkylsilanes (e.g., benzylsilane, 3-phenoxyphenyl-1-silabutane, 3-naphthyl-1-silabutane, and 3-chlorophenyl-1-silabutane) was performed to produce poly(MMA)s containing the corresponding silyl moiety as an end group. It was found for the phenylsilane that while the polymerization yields increased and then decreased with a turning point at the molar ratio of MMA:silane=10:1 as the relative silane concentration increases, the polymer molecular weights decreased, and the TGA residue yields and the relative intensities of SiH IR stretching bands increased with increment of molar ratio of silane over MMA. The photopolymerization yield of MMA with the arylsilane was found to be higher than those with the alkylsilanes and without the silanes. Thus, the silanes seemed to significantly influence on the photopolymerization as both chain initiation and chain transfer agents.

Homolytic Reactions of Isonitriles (이소니트릴의 자유라디칼반응)

  • Sung Soo Kim
    • Journal of the Korean Chemical Society
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    • v.24 no.3
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    • pp.250-258
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    • 1980
  • Various radicals may add to isonitriles to give imidoyl radcals RN=CR'. This may be also generated via abstraction of imidoyl hydrogen from imine in the following manner: RN=CR' + R"${\cdot}{\rightarrow}$ RN=CR' + R"-H Imidoyl radicals would be stabilized via two pathways, ${\beta}$-cleavage and atom transfer reactions. ${\beta}$-Cleavage may occur in two directions depending upon structure of the radicals. Cyanide transfer and the "so-called" normal ${\beta}$-cleavage are the two modes of ${\beta}$-cleavage. Addition of t-butoxy radical to t-butyl isocyanide 7 generates an imidoyl radical t-Bu-N=C-O-Bu-t, which undergoes ${\beta}$-cleavage to give t-butyl isocyanate and t-butyl radical. Addition of phenyl radical to 7 forms the intermediate radical t-Bu-N=$C-C_6H_5$, which decomposes to give benzonitrile and t-butyl radical. The t-butyl radical generated from the ${\beta}$-cleavage adds to 7 giving the radical t-Bu-N=C-Bu-t, which cleaves only to pivalonitrile and t-butyl radical, inducing radical chain isomerization. Trimethylsilyl radical adds to 7 to give the intermediate t-Bu-N=$C-Si(CH_3)_3$, which collapses to $(CH_3)_3$SiCN and a t-butyl radical.

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