Synthesis, Reactivity, and Structural Characterization of Organolanthanide Compounds Incorporating both Cyclopentadienyl and Carboranyl Groups

Reaction of Me 2 Si(C 5 H 5 )Cl with 1 equiv of Li 2 C 2 B 10 H 10 in toluene/ether at 0 °C, after hydrolysis, gave Me 2 Si(C 5 H 5 )(C 2 B 10 H 11 ) ( 1 ) in 79% isolated yield. 1 can be conveniently converted into the monoanion [Me 2 Si(C 5 H 4 )(C 2 B 10 H 11 )]Na ( 2 ), the dianion [Me 2 Si(C 5 H 4 )(C 2 B 10 H 10 )]Li 2 ( 3 ), and the trianion [Me 2 Si(C 5 H 4 )(C 2 B 10 H 11 )]K 3 ( 4 ) by treatment with NaH, MeLi, and K metal in THF at room temperature, respectively. 2 reacted with 1 equiv of LnCl 3 in THF to give [η 5 -Me 2 Si(C 5 H 4 )(C 2 B 10 H 11 )]LnCl 2 (THF) 3 (Ln = Nd ( 5 ), Sm ( 6 ), Er ( 7 ), Yb ( 8 )) in good yield. Treatment of LnCl 3 with 2 equiv of 2 or reaction of [η 5 -Me 2 Si(C 5 H 4 )(C 2 B 10 H 11 )]LnCl 2 (THF) 3 with an equimolar amount of 2 in THF resulted in the isolation of [η 5 -Me 2 Si(C 5 H 4 )(C 2 B 10 H 11 )] 2 LnCl(THF) 2 (Ln = Nd ( 9 ), Sm ( 10 ), Y ( 11 ), Gd ( 12 ), Yb ( 13 )) in good yield. Interaction of 3 with LnCl 3 in THF in a molar ratio of 1:1 or 2:1 or reaction of [η 5 -Me 2 Si(C 5 H 4 )(C 2 B 10 H 11 )] 2 LnCl(THF) 2 with 2 equiv of MeLi in THF gave the same compounds [{η 5:σ-Me 2 Si(C 5 H 4 )(C 2 B 10 H 10 )} 2 Ln][Li(THF) 4 ] (Ln = Nd ( 14 ), Y ( 15 ), Er ( 16 ), Yb ( 17 )). Treatment of NdCl 3 with an equimolar amount of 4 in THF or reaction of [η 5 -Me 2 Si(C 5 H 4 )(C 2 B 10 H 11 )]NdCl 2 (THF) 3 with excess K metal in THF produced [η 5:η 6 -Me 2 Si(C 5 H 4 )(C 2 B 10 H 11 )]Nd(THF) 2 ( 18 ). Under similar reaction conditions, however, interaction of LnCl 3 (Ln = Sm, Yb) with 4 in THF afforded the organolanthanide(II) compounds {[η 5:η 6 -Me 2 Si(C 5 H 4 )(C 2 B 10 H 11 )]Ln II (THF) 2 }{K(THF) 2 } (Ln = Sm ( 20 ), Yb ( 21 )). The Sm analogue of 18, [η 5:η 6 -Me 2 Si(C 5 H 4 )(C 2 B 10 H 11 )]Sm(THF) 2 ( 19 ), was prepared from an unprecedented redox reaction of SmI 2 with 2 equiv of 2 in THF. Reaction of 19 with excess K metal in THF gave 20 . Unlike the SmI 2 case, interaction of YbI 2 with 2 equiv of 2 in THF gave [η 5 -Me 2 Si(C 5 H 4 )(C 2 B 10 H 11 )] 2 Yb II (THF) 2 ( 22 ). All of these compounds were characterized by various spectroscopic and elemental analyses. The solid-state structures of compounds 5, 8, 9, 10, 14, 15, 16, 17, 19, and 22 were confirmed by single-crystal X-ray analyses. The reaction mechanism of the formation of 19 is also proposed.