Compounds of germanium, tin, and lead, 30 - A heteroleptic diplumbene and a magnesium dibromide stabilized plumbylene dimer

Treatment of the diarylplumbylene R2Pb: (R = 2,4,6-iPr(3)C(6)H(2)) with the disilylplumbylene R'Pb-2: [R' = Si(SiMe3)(3)] furnishes the heteroleptic p lumbylene RR'Pb: which exists as the diplumbene RR'Pb=PbRR' (7) in the soli d state. The X-ray structure analysis of 7 reveals a trans-bent angle of 42 .7 degrees and a Pb-Pb bond length of 298.99(5) pm, the shortest observed s o far for diplumbenes with a lead-lead double bond. Reaction of mesitylmagn esium bromide with PbCl2 yielded black crystals of an MgBr2 stabilized dime sitylplumbylene dimer with a large trans-bent angle of 71 degrees, a lead-l ead separation of 335.49(6) pm, and long Pb ... Br contacts of 315.71(8) pm .