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 iPr2NP(C9H7)Cl (1) with 1 equiv of Li2C2B10H10 gave, after treatment with 1 equiv of n-BuLi, the dilithium salt [iPr2NP(C9H6)(C2B10H10)]Li2(OEt2)1.5 (2). 2 can be conveniently converted into its neutral counterpart iPr2NP(C9H7)(C2B10H11) (4) by treatment with excess dry Me3NHCl in CH2Cl2. Mixing 2 and 4 in a 1:1 molar ratio afforded quantitatively the monolithium salt [iPr2NP(C9H6)(C2B10H11)]Li(DME)3 (3). Reaction of YbI2 with 1 equiv of 2 gave the organoytterbium(II) complex [η5:σ-iPr2NP(C9H6)(C2B10H10)]Yb(DME)2 (5). 5 reacted further with 1 equiv of 3 to afford the organoytterbium(III) complex [{η5:σ-iPr2NP(C9H6)(C2B10H10)}2Yb][Li(THF)3(Et2O)] (6). In sharp contrast, treatment of SmI2 with 1 equiv of 2 generated the trivalent organosamarium complex [{η5:σ-iPr2NP(C9H6)(C2B10H10)}2Sm][Li(DME)3] (7). Reaction of LnCl3 with 2 equiv of 2 gave the ionic complexes [{η5:σ-iPr2NP(C9H6)(C2B10H10)}2Ln][Li(L1)nL2]] (L1 = L2 = DME, n = 2, Ln = Sm (7), Nd (8), Er (9); L1 = DME, L2 = THF, n = 2, Ln = Y (10)). Reaction between equimolar amounts of LnCl3 and 2 resulted in the isolation of the lanthanocene chlorides [{[η5:σ-iPr2NP(C9H6)(C2B10H10)]LnCl}2(μ-Cl)3Li(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 KCH2Ph afforded the unexpected compound {[η5:σ-iPr2NP(C9H6)(C2B10H10)]2Y}{(η6-C6H5CH3)2K} (13) and treatment of 12 with 2 equiv of NaBH4 produced the organoyttrium hydrides [{η5:σ-iPr2NP(C9H6)(C2B10H10)}Y{(μ-H)3BH}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.