Synthesis, Structural Characterization, and Reactivity of Rare-Earth Complexes Derived from A New Phosphorus-Bridged Versatile Ligand, <i>ⁱ</i>Pr₂NP(C₉H₇)(C₂B₁₀H₁₁)

Abstract

New phosphorus-bridged ligands incorporating both indenyl and carboranyl moieties were prepared. Reaction of i Pr 2 NP(C 9 H 7 )Cl ( 1 ) with 1 equiv of Li 2 C 2 B 10 H 10 gave, after treatment with 1 equiv of n -BuLi, the dilithium salt [ i Pr 2 NP(C 9 H 6 )(C 2 B 10 H 10 )]Li 2 (OEt 2 ) 1.5 ( 2 ). 2 can be conveniently converted into its neutral counterpart i Pr 2 NP(C 9 H 7 )(C 2 B 10 H 11 ) ( 4 ) by treatment with excess dry Me 3 NHCl in CH 2 Cl 2 . Mixing 2 and 4 in a 1:1 molar ratio afforded quantitatively the monolithium salt [ i Pr 2 NP(C 9 H 6 )(C 2 B 10 H 11 )]Li(DME) 3 ( 3 ). Reaction of YbI 2 with 1 equiv of 2 gave the organoytterbium(II) complex [ η 5: σ - i Pr 2 NP(C 9 H 6 )(C 2 B 10 H 10 )]Yb(DME) 2 ( 5 ). 5 reacted further with 1 equiv of 3 to afford the organoytterbium(III) complex [{ η 5: σ - i Pr 2 NP(C 9 H 6 )(C 2 B 10 H 10 )} 2 Yb][Li(THF) 3 (Et 2 O)] ( 6 ). In sharp contrast, treatment of SmI 2 with 1 equiv of 2 generated the trivalent organosamarium complex [{ η 5: σ - i Pr 2 NP(C 9 H 6 )(C 2 B 10 H 10 )} 2 Sm][Li(DME) 3 ] ( 7 ). Reaction of LnCl 3 with 2 equiv of 2 gave the ionic complexes [{ η 5: σ - i Pr 2 NP(C 9 H 6 )(C 2 B 10 H 10 )} 2 Ln][Li(L 1 ) n L 2 ]] (L 1 = L 2 = DME, n = 2, Ln = Sm ( 7 ), Nd ( 8 ), Er ( 9 ); L 1 = DME, L 2 = THF, n = 2, Ln = Y ( 10 )). Reaction between equimolar amounts of LnCl 3 and 2 resulted in the isolation of the lanthanocene chlorides [{[ η 5: σ - i Pr 2 NP(C 9 H 6 )(C 2 B 10 H 10 )]LnCl} 2 ( μ -Cl) 3 Li(DME)][Li(DME) 3 ] 2 (Ln = Er ( 11 ), Y ( 12 )). The chloro groups in these complexes can be replaced by other moieties. For example, reaction of 12 with 2 equiv of KCH 2 Ph afforded the unexpected compound {[ η 5: σ - i Pr 2 NP(C 9 H 6 )(C 2 B 10 H 10 )] 2 Y}{( η 6 -C 6 H 5 CH 3 ) 2 K} ( 13 ) and treatment of 12 with 2 equiv of NaBH 4 produced the organoyttrium hydrides [{ η 5: σ - i Pr 2 NP(C 9 H 6 )(C 2 B 10 H 10 )}Y{( μ -H) 3 BH} 2 ][Li(DME) 3 ] ( 14 ). All complexes were fully characterized by various spectroscopic techniques and elemental analyses. The structures of some of the compounds were further confirmed by single-crystal X-ray analyses.