Abstract
The hydride-bridged silylium cation [Et(3) Si-H-SiEt(3) ](+) , stabilized by the weakly coordinating [Me(3) NB(12) Cl(11) ](-) anion, undergoes, in the presence of excess silane, a series of unexpected consecutive reactions with the valence-isoelectronic molecules CS(2) and CO(2) . The final products of the reaction with CS(2) are methane and the previously unknown [(Et(3) Si)(3) S](+) cation. To gain insight into the entire reaction cascade, numerous experiments with varying conditions were performed, intermediate products were intercepted, and their structures were determined by X-ray crystallography. Besides the [(Et(3) Si)(3) S](+) cation as the final product, crystal structures of [(Et(3) Si)(2) SMe](+) , [Et(3) SiS(H)Me](+) , and [Et(3) SiOC(H)OSiEt(3) ](+) were obtained. Experimental results combined with supporting quantum-chemical calculations in the gas phase and solution allow a detailed understanding of the reaction cascade.