CHEMISTRY OF C-TRIMETHYLSILYL-SUBSTITUTED HETEROCARBORANES .19. SYNTHETIC AND STRUCTURAL STUDIES ON TRINUCLEAR LN(III) CARBORANE CLUSTERS [LN(III)=SM, GD, TB, DY, HO] .1. CONVERSION TO SANDWICHED MANGANESE(II)AND COBALT(III) CARBORANE COMPLEXES

The reaction of 4,5-Li(THF)(2)-1-Li(THF)(2)-2,3-(SiMe(3))(2)C2B4H4 wit h anhydrous LnCl(3) (Ln = Sm, Gd, Tb, Dy, Ho), in a molar ratio of 2:1 in dry benzene (C6H6), produced the sandwiched paramagnetic species ) )(2)-2,3-C2B4H4](3)[(mu(2)-1-Li-2,3-(SiMe(3))(2)- B4H4)(3)(mu(3)-OMe)] [mu(2)-Li(C4H8O)](3)(mu(3)-O)} (Ln = Sm (1), Gd (2), Tb (3), Dy (4), H o (5)) in 59%, 58%, 49%, 52%, and 59% yields, respectively. All compou nds were characterized by IR spectroscopy and by single-crystal X-ray diffraction studies; compound 1 was also characterized by H-1, B-11, a nd C-13 NMR spectroscopy. Compounds 1-5 are isostructural clusters con sisting of three half-sandwich lanthanacarboranes, three lithiacarbora nes, three bridging lithium atoms, and three THF molecules of solvatio n. Their structures are such that the nine metal atoms form a tricappe d trigonal prism with the lanthanide metals at the capping positions. The reaction of 2 with MnCl2 in benzene, followed by the addition of T MEDA, gave a dinuclear manganacarborane sandwich complex, EDA)-1,1'-co mmo-Mn[2,3-(SiMe(3))(2)-2,3-C2B4H4](2) (6) Compound 6 was characterize d on the basis of its elemental analysis and IR spectrum and also by X -ray diffraction. The reaction of 1 with CoCl2 in dry benzene, followe d by the addition of TMEDA, gave the cobalt(III) sandwich complex, (2) {1,1'-commo-Co[2,3-(SiMe(3))(2)-2,3-C2B4H4](2)} (7). Complex 7 was cha racterized on the basis of H-1, Li-7, B-11, and C-13 NMR spectra and I R spectra and also by X-ray diffraction.