Sidearm Effects. Synthesis, Structural Characterization, and Reactivity of Rare Earth Complexes Incorporating a Linked Carboranyl-Indenyl Ligand with a Tethered Oxygen Atom

New ether-functionalized carboranyl-indenyl hybrid ligands were prepared. They can prevent lanthanocene chlorides from ligand redistribution reactions and offer samarium(II) complexes unusual reactivities. Treatment of Me 2 SiCl(C 9 H 6 CH 2 CH 2 OMe) with 1 equiv of Li 2 C 2 B 10 H 10 in toluene/Et 2 O afforded the monolithium salt [Me 2 Si(C 9 H 5 CH 2 CH 2 OMe)(C 2 B 10 H 11 )]Li(OEt 2 ) ( 2 ). Interaction of 2 with 1 equiv of n -BuLi in Et 2 O produced the dilithium salt [Me 2 Si(C 9 H 5 CH 2 CH 2 OMe)(C 2 B 10 H 10 )]Li 2 (OEt 2 ) 2 ( 3 ). Reaction of 3 with 1 equiv of LnCl 3 at room temperature gave the complex salts of general formula [{[η 5:σ-Me 2 Si(C 9 H 5 CH 2 CH 2 OMe)(C 2 B 10 H 10 )]Ln(THF)(μ-Cl) 3 Ln[η 5:η 1:σ-Me 2 Si(C 9 H 5 CH 2 CH 2 OMe)(C 2 B 10 H 10 )]} 2 {Li(THF)}][Li(THF) 4 ] (Ln = Y ( 4 ), Yb ( 5 )). Upon heating, 5 was converted into [η 5:η 1:σ-Me 2 Si(C 9 H 5 CH 2 CH 2 OMe)(C 2 B 10 H 10 )]Yb(THF)(μ-Cl) 2 Yb[η 5:η 1:σ-Me 2 Si(C 9 H 5 CH 2 CH 2 OMe)(C 2 B 10 H 10 )] ( 6 ) by eliminating LiCl. Treatment of 4 or 5 with 2 equiv of group 1 metal amides gave organo-rare-earth amide complexes [η 5:η 1:σ-Me 2 Si(C 9 H 5 CH 2 CH 2 OMe)(C 2 B 10 H 10 )]Y(NHC 6 H 3 -2,5- t Bu 2 )(μ-Cl)Li(THF) 3 ( 8 ) or [η 5:η 1:σ-Me 2 Si(C 9 H 5 CH 2 CH 2 OMe)(C 2 B 10 H 10 )]Yb(NHC 6 H 3 -2,6- i Pr 2 )(μ-Cl)Li(THF) 3 ( 9 ). An equimolar reaction of SmI 2 with 3 in THF generated, after addition of LiCl, [{[η 5:σ-Me 2 Si(C 9 H 5 CH 2 CH 2 OMe)(C 2 B 10 H 10 )] 2 Sm}{Li(THF)}] n ( 10 ) and [{η 5:η 1:η 6 -Me 2 Si(C 9 H 5 CH 2 CH 2 OMe)(C 2 B 10 H 10 )Sm} 2 (μ-Cl)][Li(THF) 4 ] ( 11 ). In sharp contrast, a less reactive YbI 2 reacted with 3 in THF, producing only salt metathesis product [η 5:η 1:σ-Me 2 Si(C 9 H 5 CH 2 CH 2 OMe)(C 2 B 10 H 10 )]Yb(DME)(THF) ( 12 ). 12 reacted with 1 equiv of 3 to give the ionic complex {[(μ-η 5:η 2 ):η 1:σ-Me 2 Si(C 9 H 5 CH 2 CH 2 OMe)(C 2 B 10 H 10 )] 2 Yb}{Li(THF) 2 } 2 ( 13 ). All complexes were characterized by various spectroscopic techniques and elemental analyses. The structures of 5, 6, and 8 − 13 were further confirmed by single-crystal X-ray analyses.