Description:
<jats:title>Abstract</jats:title><jats:p>A detailed quantum‐chemical study on the amine‐induced disproportionation reaction of perchlorinated silanes to <jats:italic>neo</jats:italic>‐Si<jats:sub>5</jats:sub>Cl<jats:sub>12</jats:sub> is reported. The key intermediate in the resulting mechanistic scenario is a dichlorosilylene amine adduct, which is in tune with recent experimental findings. Yet, at variance with the generally accepted notion of silicon‐chain growth by concerted silylene insertion into Si−Cl bonds of lower silanes, the formation of <jats:italic>neo</jats:italic>‐Si<jats:sub>5</jats:sub>Cl<jats:sub>12</jats:sub> follows more complex pathways. The reactivity is dominated by the Lewis–base character of the dichlorosilylene amine adduct and characterized by three elementary steps that bear close resemblance to the key elementary steps identified earlier for the chloride‐induced disproportionation of Si<jats:sub>2</jats:sub>Cl<jats:sub>6</jats:sub>. NBO and QTAIM analyses of the key reactive species SiCl<jats:sub>2</jats:sub><jats:bold>⋅</jats:bold>NMe<jats:sub>3</jats:sub> and SiCl<jats:sub>3</jats:sub><jats:sup>−</jats:sup> provide a rationale for these striking similarities.</jats:p>