| Research Abstract |
(a) Condensation of 1, 1, 1-tribormo-2, 2, 2-triethyldisilane with sodium afforded ploy (triethylsilylsilyne) (1) in 70% yield. Gel permeation chromatography of 1 indicated a Mw=1400 versus polystyrene,in a single envelope with polydispersity of 1.04. Characterization was achieved by ^<29>Si, ^<13>C, and ^1H NMR spectrocopy, and infrared spectrocopy. The ^<29>Si NMR spectrum of 1 exhibited broad resonance centered at +150 ppm, which was assigned to the sp^2 Si atoms of the oligomer backbone.
(b) Electrochemical properties of iodine-doped sample of 1 was measured. The completely doped sample was obtained as black precipitate from the dichloromethane solution of 1 and iodine.
The sample showed a metallic behavior, first observed for organosilicon compounds, above 170 K and became semiconducting eith an activation energy, Ea, of 0.3 meV.
(c) Novel unsaturated cyclopolysilanes such as tetrasilacyclobutene and octasilacycloocta-1, 5-diene were generated photochemically from dodecaisopropyltricyclo [4.2.0.0^<2, 5>] octasilane (2). When a solution of 2 and methanol in cyclohexane was irradiated for 3 min at room temperature, with a high-pressure mercury lamp, 2 was cleanly photoalyzed to give 1-methoxy-1, 2, 3, 3, 4, 4-hexaisopropylcyclotetrasilane exclusively. The formation of the cycloterasilane is indicative of the formation of a tetetrasilacyclobutene intermediate, which could be trapped by methanol. Similar photolysis of the syn isomer was found to afford lead a dodecaisopropyloctasilacycloocta-1, 5-diene intermediate, which could be trapped by methanol.
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