Reaction of a diaryldigermyne with ethylene.

Reaction of the stable digermyne BbtGe[triple bond, length as m-dash]GeBbt (Bbt = 2,6-[CH(SiMe)]-4-[C(SiMe)]-CH) with ethylene initially afforded the corresponding 1,2-digermacyclobutene. Depending on the reaction conditions applied, further reaction of this 1,2-digermacyclobutene with ethylene furnished two different reaction products: a 1,4-digermabicyclo[2.2.0]hexane or a bis(germiranyl)ethane. Combined experimental and theoretical results suggested that the 1,4-digermabicyclo[2.2.0]hexane and the bis(germiranyl)ethane are the thermodynamic and kinetic reaction products, respectively. A reaction mechanism in agreement with these results was proposed.