Diiodotetrasupersilylcyclotetrasilene (tBu3Si)4Si4I2—A Molecule Containing an Unsaturated Si4 Ring

The red-orange tetrasilacyclobutene 1 (R*=SitBu₃) is formed quantitatively by the reaction of tetrasilatetrahedrane 2 and iodine. Surprisingly, water and methanol do not react with 1 with addition to the Si−Si double bond, but instead with replacement of the silicon-bound iodine atoms with oxygen or the methoxy group, respectively. The substitutions possibly proceed by dissociative activation via intermediate 3 .