A Bis(silylene)silole - synthesis, properties and reactivity.

A 1,1-bis(silylene)silole has been synthesised by a double salt-metathesis reaction from potassium silacyclopentadienediide, K[1], and an amidinato-stabilized silylene chloride in a 1 : 2 ratio. The red colour of the title compound is due to the lp(Si)/π*(silole) transition. This band is bathochromically shifted compared to that of other 1,1-bissilylsiloles suggesting enhanced conjugation between the silole π-system and the newly formed Si(II)-Si(IV)-Si(II) group. The bissilylene is easily oxidised by the elemental chalcogens S, Se, and Te and forms a bissilaimide by reaction with an arylazide.