Unusual Reactivity of a Disilyne with 4-Dimethylaminopyridine: Formation of an Intramolecularly N-Coordinated Silylene and Its Isomerization to a Zwitterionic Silyl Anion

Reaction of isolable 1,1,4,4-tetrakis[bis(trimethylsilyl)methyl]-1,4-diisopropyltetrasila-2-yne (1) with an equiv amount of 4-dimethylaminopyridine unexpectedly produced the intramolecularly N-coordinated silylene 2 as the primary product. However, 2 was not thermally stable at room temperature in solution and slowly isomerized to silyl anion 3 with a zwitterionic structure via 1,2-hydrogen migration followed by Si–N bond formation.