Ring Expansion of Cyclic Triplatinum(0) Silylene Complexes Induced by Insertion of Alkyne into a Si–Pt Bond

Triangular triplatinum(0) complexes with bridging diarylsilylene ligands, [{Pt­(PMe3)}3(μ-SiAr2)3] (1: Ar = Ph, 2: Ar = C6H4F-4), reacted with dimethyl acetylenedicarboxylate to afford new Pt3 complexes. The equimolar reaction of complex 1 produced a linear triplatinum complex with μ2-diphenylsilylene and μ3-phenyl­(vinylene)­silylene ligands. The latter ligand was formed via migration of a Ph group of the bis­(diphenylsilyl)­ethylene ligand. The reaction of 2 with the alkyne in a 1:3 molar ratio yielded the product having a disilaplatinacyclic moiety and a Pt center with the donor-stabilized silylene ligand, and they were separated by the coordinated alkyne molecule. A common intermediate having a disilaplatinacyclopentene group was converted into the respective triplatinum complexes, depending on the substituents of the silylene ligand.