A Heteroleptic Diplumbene and a Magnesium Dibromide Stabilized Plumbylene Dimer

Treatment of the diarylplumbylene R2Pb: (R = 2,4,6-iPr3C6H2) with the disilylplumbylene R′2Pb: [R′ = Si(SiMe3)3] furnishes the heteroleptic plumbylene RR′Pb: which exists as the diplumbene RR′Pb=PbRR′ (7) in the solid state. The X-ray structure analysis of 7 reveals a trans-bent angle of 42.7° and a Pb–Pb bond length of 298.99(5) pm, the shortest observed so far for diplumbenes with a lead–lead double bond. Reaction of mesitylmagnesium bromide with PbCl2 yielded black crystals of an MgBr2 stabilized dimesitylplumbylene dimer with a large trans-bent angle of 71°, a lead–lead separation of 335.49(6) pm, and long Pb···Br contacts of 315.71(8) pm.