Chemical Properties of Tetragermaplatinacyclopentane. Insertion of an Alkyne into a Pt–Ge Bond and Silylation Caused by H2SiPh2

A platinum complex having dibutylgermyl ligands, [Pt(GeHBu2)2(dmpe)] (dmpe = 1,2-bis(dimethylphosphino)ethane), reacted with excess H2GeBu2 at 90 °C to yield a five-membered tetragermaplatinacycle, [Pt(GeBu2GeBu2GeBu2GeBu2)(dmpe)] (6). The direct reaction of H2GeBu2 with [Pt(dmpe)2] in 5:1 ratio also gave 6 in 67% yield. The reaction of dimethyl acetylenedicarboxylate with 6 caused insertion of a CC bond into a Pt–Ge bond to form a seven-membered germaplatinacycloheptene, which was characterized by X-ray crystallography. Complex 6 reacted with H2GePh2 and H2SiPh2 in 1:2 ratio to produce a mixture of tetragermane dihydride H(GeBu2)4H and bis(silyl)- or bis(germyl)platinum complexes [Pt(EHPh2)2(dmpe)] (E = Si, Ge).