The Cyclo[(disilanylene)(butadiyne)]s [(i-Pr)2Si(i-Pr)2SiC≡CC≡C]n (n = 2–4)

The new type of the twelve- to twenty-four-membered rings [(i-Pr) 2 Si(i-Pr) 2 SiC≡CC≡C] n (1, n = 2; 2, n = 3; 3, n = 4) were synthesized and the molecular structures of 1 and 2 were analyzed by X-ray crystallography. The compounds show unusual electronic properties due to the interaction of the C≡C π orbitals with the Si-Si σ bonds.