Bis[2-((dimethylamino)methyl)ferrocenyl]lead, (FcN)(2)Pb, as a ligand: Synthesis and characterization of the heterotrimetallic metalloplumbylene compounds (FcN)(2)PbM(CO)(5) (M = Cr, Mo, W)

The reaction of [FE(eta (5)-C5H5)(eta (5)-C5H3(CH2-NMe3-(2))-2)-C,N](2)Pb, (FcN)sPb (1), with the group 6 carbonyl derivatives M(CO)(5)L (M = Cr, W, L = THF; M = Mo, L = THF, NMe3) affords the heterotrimetallic plumbylene add ucts (FcN)(2)PbM(CO)(5) (M = Cr (2), Mo (3), W (4)) in excellent yield. All compounds were characterized by elemental analysis, X-ray crystallography, and IR and H-1 and C-13 NMR spectroscopy. The results show that the metall oplumbylenes 2-4 exist solely as meso diastereomers, both in the solid stat e and in solution, although the starting compound 1 consists in solution of a mixture of two interconverting diastereomers, rac- and meso-(FcN)(2)Pb. The Pb-M bond lengths are indicative of some degree of pi -bonding.