A Disilene Base Adduct with a Dative Si-Si Single Bond

An experimental and theoretical study of the base‐stabilized disilene 1 is reported, which forms at low temperatures in the disproportionation reaction of Si2Cl6 or neo‐Si5Cl12 with equimolar amounts of NMe2Et. Single‐crystal X‐ray diffraction and quantum‐chemical bonding analysis disclose an unprecedented structure in silicon chemistry featuring a dative Si→Si single bond between two silylene moieties, Me2EtN→SiCl2→Si(SiCl3)2. The central ambiphilic SiCl2 group is linked by dative bonds to the amine donor and the bis(trichlorosilyl)silylene acceptor, which leads to push–pull stabilization. Based on experimental and theoretical examinations a formation mechanism is presented that involves an autocatalytic reaction of the intermediately formed anion Si(SiCl3)3− with neo‐Si5Cl12 to yield 1. Geben und nehmen: Ein Perchlordisilen‐Amin‐Addukt mit einer ungewöhnlichen gewinkelten Struktur (siehe Bild) wurde durch Kristallisation isoliert. Eine quantenchemische Bindungsanalyse offenbart dative N1→Si1‐ und Si1→Si2‐Bindungen, die zu einer Push‐Pull‐Stabilisierung der zentralen SiCl2‐Gruppe führen.