LAUSR

4,4-Dihydrodithienosilole (DTSH2) was isolated from a mixture of 3,3′-dibromobithiophene, n-BuLi, and H2SiCl2 and was fully characterized. The reaction of DTSH2 with a Pt(0) complex, prepared in situ from [Pt(PCy3)2] and DPPE (1,2-bis(diphenylphosphino)ethane), produced a bis(silyl)platinum complex [Pt(DTSH)2(dppe)] (1) with two hydrodithienosilole ligands. DTSH2 undergoes cyclodimerization accompanied by skeletal rearrangement to afford a cis-fused bicyclic compound (2) upon heating the solution in the presence of a catalytic amount of 1 or [Ni(PPh3)4]. The product has a Si–Si bond that bridges two Si atoms, separated by 2.309(1) A. Bicyclic disilane 2 forms the Pt complex (3) with two Si ligands and retaining the 10-membered macrocycle ligand via the Si–Si bond cleavage.