A SYSTEMATIC SYNTHETIC APPROACH TO A NOVEL, MIXED 2,3-C2B4-ERBIUM(III) AND 2,4-C2B4-ERBIUM(III) CARBORANE BENT-SANDWICH COMPLEX

The reaction between -Li(TMEDA)-1-Li(TMEDA)-2,3-(SiMe(3))(2)-2,3-C2B4H 4 (1a) and anhydrous ErCl3, in a molar ratio of 2:1, in dry benzene at 0 degrees C produced, in 93% yield, a novel Er(III) bent-sandwich com plex, [(mu-H)(3)Li(TMEDA)]-1,1'-commo-Er(2,3-C2B4H4)(2)] (2), as an or ange crystalline solid. The reaction of 2 with 1 equiv of -Li(TMEDA)-1 -Li(TMEDA)-2,4-(SiMe(3))(2)-2,4-C2B4H4 (1b) in dry benzene at 0 degree s C produces the pink, dimeric Er(III) mixed-carborane bent-sandwich c omplex {Li(TMEDA)(2)}(2){commo-1-[2, 2,3-C2B4H4]-1-Er-[2,4-(SiMe(3))(2 )-2,4-C2B4H4]}(2) (3) in 95% yield, thus demonstrating a possible gene ral synthetic route to mixed-carborane metal complexes.