YLSILYL)-2,3-DICARBA-1-PLUMBA-CLOSO-HEPTABORANE(6)

The title compound, 1-Pb[(eta5-C5H5)Fe{eta5-C5H4-CH2 (CH3)2N}]-2-(CH3) -3-[Si(CH3)3]-2,3-C2B4H4] (3) was crystallized in the monoclinic space group P2(1)/n. The structure of this complex is quite similar to thos e found for the corresponding germa-, stanna- and plumbacarborane anal ogues of the formula 1-M[(eta5'-C5H5) {eta5-C5H4CH2(CH3)2N}]-2,3-[Si(C H3)3]2-2,3-C2B4H4] [M = Sn (1); M = Ge and Pb (2)]. As in (1) and (2) the dihedral angles between the C5H5 and C2B3 planes in (3) are about 91-degrees. This is the result of a slight rotation of the ferrocenyl ligand about the C(11)-C(21) bond making the Pb-C(12) bond a distance of closest approach and thus establishing the existence of secondary m etal-C5H5 (pi) interactions in the stabilization of these donor-accept or complexes.