Synthesis, Structure, and Reactivity of Organolanthanide Carboranyl Compounds and Lanthanacarboranes Derived from a Versatile Ligand, Me2C(C5H5)(C2B10H11)

The compound Me2C(C5H5)(C2B10H11) (I) could be conveniently converted into the monoanion [Me2C(C5H4)(C2B10H11)]- (I-1) and the dianion [Me2C(C5H4)(C2B10H10)]2- (I-2) by treatment with excess NaH and 2 equiv of n-BuLi, respectively. The monoanion I-1 could be further converted into the trianion [Me2C(C5H4)(nido-C2B10H11)]3- (I-3) by reaction with 2 equiv of Na metal in THF and into the pentaanion [Me2C(C5H4)(arachno-C2B10H11)]5- in the presence of LnCl3 and excess Na metal in THF. Reactions of LnCl3 with the monoanion I-1 in molar ratios of 1:1, 1:2, and 1:3 generated the mono-, bis-, and tris-ligated organolanthanide compounds [η 5-Me2C(C5H4)(C2B10H11)]LnCl2(S)n ((S)n = (THF)3, Ln = Er (1), Sm (2); (S)n = (DME)2, Ln = Nd (3)), [η 5-Me2C(C5H4)(C2B10H11)]2SmCl(THF)2 (4), and [η 5-Me2C(C5H4)(C2B10H11)]3Sm·0.5C7H8 (5), respectively. Reaction of LnCl3 with 1 or 2 equiv of the dianion I-2 gave the same compound, [{η 5:σ-Me2C(C5H4)(C2B10H10)}2Ln][Li(DME)3] (Ln = Sm (6), Yb (7)). 6 could also be prepared by treatment of 2 with 1 equiv of the dianion I-2. Reaction of YbI2 with 1 equiv of I-2, followed by treatment with 1 equiv of I-1, also gave compound 7. However, YbI2 reacted with 2 equiv of I-1 to afford the organoytterbium(II) compound [η 5-Me2C(C5H4)(C2B10H11)]2Yb(THF)2 (8). Interaction of SmI2 with 2 equiv of I-1 yielded two compounds, the redox product [η 5:η 6-Me2C(C5H4)(C2B10H11)]Sm(THF)2 (9) and the tris-ligated compound 5. The compound [η 5:η 6-Me2C(C5H4)(C2B10H11)]Er(THF)2 (10), an analogue of 9, was prepared by treatment of 1 with 2 equiv of Na metal or by reaction of ErCl3 with 1 equiv of I-3. Treatment of 10 with excess Na metal gave the first organolanthanide compound containing a η 7-carboranyl ligand, [{[η 5:η 7-Me2C(C5H4)(C2B10H11)]Er}2{Na4(THF)9}] n (11). Its Dy analogue, [{[η 5:η 7-Me2C(C5H4)(C2B10H11)]Dy}2{Na4(THF)9}] n (12), could also be prepared by a “one-pot” reaction of DyCl3, I-1, and excess Na metal. Treatment of 11 with 2 equiv of ErCl3 in THF gave the novel tetranuclear cluster [{η 5:η 7-Me2C(C5H4)(C2B10H11)}Er2(μ-Cl)(THF)3]2 (13), in which the Er3+ ions replace all Na+ ions in 11. All of these compounds were fully characterized by various spectroscopic data and elemental analyses. The solid-state structures of compounds 4−11 and 13 have been confirmed by single-crystal X-ray analyses.