Activation of CS(2) and CO(2) by Silylium Cations

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.