C-Chlorinated, SiH-Containing Carbosilanes

The product is a limpid colorless liquid with an odor typical of SiH-containing carbosilanes, with bp. 83 ° (extrapolated from the vapor pressure measurement). It can be stored successfully in a sealed glass tube, but in contact with traces of H2O or air, polymerization occurs. While pure (11381)2 l2 remains unchanged over a period of years, in the presence of Al l3 at 20 ° it degrades over a period of months the starting material is completely consumed. Thirty percent of the 8i in (11381)2 l2 is converted to 8iH. are present are 

The cyclic compound (H28i— 12)3 was isolated as a pure product in approximately 50% yield by the reaction 

The bond energy of Si—Cl is higher than that of C—Cl, while the bond energy of C—H is much higher than that of Si—H. Hence transfer of Cl from C to Si, with simultaneous transfer of H from Si to C, liberates much energy. Solutions of these compounds in ether, hydrocarbon solvents, or CCl have been shown to be safe at room temperature. This explosive nature, which always appears when a pure sample of these compounds is heated, is attributed to a rearrangement, as illustrated by placing face to face the isomers of 1,3,5-trisilacyclohexane  

Notice that CH and SiCl groups exist in (Cl Si—CH2)3, which represents a thermodynamically favored arrangement of bound atoms in the molecule. In (H2Si—CCl2)3, however, the SiH and CCl groups occupy the opposite positions. The course of such explosive reactions has not been investigated in detail, however. 

The side reactions include a) the formation of CH-containing compounds, and b) the cleavage of the SiC bond. 

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