RATE CONSTANTS FOR THE REACTIONS OF CCL(X2-PI) WITH A SERIES OF SILANES

Rate constants for the gas phase reactions of CCl generated by the flash photolysis of CHBr2Cl with a series of silanes have been obtained by kinetic absorption spectroscopy. In general, the rate constants are very high, and range from (4.8 ± 0.5) × 108 (SiH4) to (6.4 ± 0.34) × 109 for Si2H6. CCl does not insert into the SiC or primary CH bonds of silanes and its rate of reaction with tertiary SiH bonds is 600 times greater than with tertiary CH bonds. CCl reacts slowly with the SiSi bond. kH/kD varies from 1.9 to 1.0 on going from primary to tertiary SiH bonds. The electrophilic character of CCl is manifested, on a per SiH bond basis, by excellent correlations between the rate constants and the hydrilic character of the SiH bond, and between log k and the ionization potential. © 1979.