Multiply-bonded Group 14 compounds theoretical studies

The above ab initio and related calculations clearly reveal that unsaturated silicon compounds are less stable than their carbon analogs (156,170), but as gas-phase studies and the chemistry of sterically crowded silicon derivatives have proved (153,154,156,158,162,172-175) such compounds can no longer be labeled as nonexistent (176,177). A number of isolable double-bonded silicon derivatives have recently been synthesized and characterized in agreement with theoretical predictions (Table III) (169,173,178-195). The data illustrate well that the kinetic stability of multiply bonded silicon species can be greatly improved by substitution of sufficiently bulky groups across the p -pw bond. The ease of addition reactions is then severely restricted. The new target for organosilicon chemists appears to be silicon triple-bonded compounds (196,197). 

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