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

The compound Me 2 C(C 5 H 5 )(C 2 B 10 H 11 ) ( I ) could be conveniently converted into the monoanion [Me 2 C(C 5 H 4 )(C 2 B 10 H 11 )] - ( I-1 ) and the dianion [Me 2 C(C 5 H 4 )(C 2 B 10 H 10 )] 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 [Me 2 C(C 5 H 4 )( nido -C 2 B 10 H 11 )] 3 - ( I-3 ) by reaction with 2 equiv of Na metal in THF and into the pentaanion [Me 2 C(C 5 H 4 )( arachno -C 2 B 10 H 11 )] 5 - in the presence of LnCl 3 and excess Na metal in THF. Reactions of LnCl 3 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 -Me 2 C(C 5 H 4 )(C 2 B 10 H 11 )]LnCl 2 (S) n ((S) n = (THF) 3, Ln = Er ( 1 ), Sm ( 2 ); (S) n = (DME) 2, Ln = Nd ( 3 )), [ η 5 -Me 2 C(C 5 H 4 )(C 2 B 10 H 11 )] 2 SmCl(THF) 2 ( 4 ), and [ η 5 -Me 2 C(C 5 H 4 )(C 2 B 10 H 11 )] 3 Sm·0.5C 7 H 8 ( 5 ), respectively. Reaction of LnCl 3 with 1 or 2 equiv of the dianion I-2 gave the same compound, [{ η 5: σ -Me 2 C(C 5 H 4 )(C 2 B 10 H 10 )} 2 Ln][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 YbI 2 with 1 equiv of I-2, followed by treatment with 1 equiv of I-1, also gave compound 7 . However, YbI 2 reacted with 2 equiv of I-1 to afford the organoytterbium(II) compound [ η 5 -Me 2 C(C 5 H 4 )(C 2 B 10 H 11 )] 2 Yb(THF) 2 ( 8 ). Interaction of SmI 2 with 2 equiv of I-1 yielded two compounds, the redox product [ η 5: η 6 -Me 2 C(C 5 H 4 )(C 2 B 10 H 11 )]Sm(THF) 2 ( 9 ) and the tris-ligated compound 5 . The compound [ η 5: η 6 -Me 2 C(C 5 H 4 )(C 2 B 10 H 11 )]Er(THF) 2 ( 10 ), an analogue of 9, was prepared by treatment of 1 with 2 equiv of Na metal or by reaction of ErCl 3 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 -Me 2 C(C 5 H 4 )(C 2 B 10 H 11 )]Er} 2 {Na 4 (THF) 9 }] n ( 11 ). Its Dy analogue, [{[ η 5: η 7 -Me 2 C(C 5 H 4 )(C 2 B 10 H 11 )]Dy} 2 {Na 4 (THF) 9 }] n ( 12 ), could also be prepared by a “one-pot” reaction of DyCl 3, I-1, and excess Na metal. Treatment of 11 with 2 equiv of ErCl 3 in THF gave the novel tetranuclear cluster [{ η 5: η 7 -Me 2 C(C 5 H 4 )(C 2 B 10 H 11 )}Er 2 ( μ -Cl)(THF) 3 ] 2 ( 13 ), in which the Er 3+ 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.