Cyclopentadienyl vs Indenyl Substituents. Organolanthanide Complexes and Biscarborane Compounds Derived from a Versatile Ligand, Me₂Si(C₉H₇)(C₂B₁₀H₁₁)

Abstract

A versatile compound, Me2Si(C9H7)(C2B10H11) can be conveniently converted into the monoanion [Me2Si(C9H6)(C2B10H11)]Na, the dianion [Me2Si(C9H6)(C2B10H10)]Na2, and the trianion [Me2Si(C9H6)(C2B10H11)]K3 by treatment with 1 equiv or excess amounts of NaH or K metal in THF, respectively. Reaction of LnCl3 with 1 equiv of [Me2Si(C9H6)(C2B10H11)]Na in THF gave dichloride complexes [η5-Me2Si(C9H6)(C2B10H11)]LnCl2(THF)3 (Ln = Nd (1), Er (2)). They can further react with another equivalent of [Me2Si(C9H6)(C2B10H11)]Na to afford monochloride complexes [η5-Me2Si(C9H6)(C2B10H11)]2LnCl(THF)2 (Ln = Ce (3), Nd (4), Sm (5), Er (6)), which can also be prepared by treatment of LnCl3 with 2 equiv of [Me2Si(C9H6)(C2B10H11)]Na in THF. 4 reacts with excess NaH in THF to produce [Na(THF)6][{η5:σ-Me2Si(C9H6)(C2B10H10)}2Nd] (7), which can also be prepared from the reaction of NdCl3 with 2 equiv of [Me2Si(C9H6)(C2B10H10)]Na2 in THF. Treatment of 2 with 2 equiv of K metal at room temperature yielded [η5:η6-Me2Si(C9H6)(C2B10H11)]Er(THF)2 (8). Reaction of 6 with 1 equiv of NaH afforded [{η5:σ-Me2Si(C9H6)(C2B10H10)}{η5-Me2Si(C9H6)(C2B10H11)}]Er(μ-Cl)Na(THF)3 (9), which can also be prepared from the reaction of 2 with 1 equiv of [Me2Si(C9H6)(C2B10H10)]Na2 in THF. Treatment of 9 with a mixture of 1 equiv of NaOH and excess NaH in THF generated the dinuclear complex [Na2(THF)11][{η5:σ-Me2Si(C9H6)(C2B10H10)}{μ-η5:σ-(C9H6)SiMe2O}Er]2 (10). Treatment of Me2Si(C9H7)(C2B10H11) with excess NaH in THF under UV-light followed by reaction with 1 equiv of LnCl3 resulted in the isolation of unprecedented biscarborane compounds [LnCl2(THF)5][μ-CH-(closo-C2B10H11)-nido-CB10H11] (Ln = Er (11), Y (12)). All of these complexes were characterized by various spectroscopic and elemental analyses. The solid-state structures of 7 and 9−12 were confirmed by single-crystal X-ray analyses.

Mono(cyclopentadienyl) Complexes of the Rare-Earth Metals

“…35 By an analogous procedure, ErCl 3 and the tripotassium salt of the corresponding ligand gave [Er(η 5 :η 6 -C 9 H 6 SiMe 2 C 2 B 10 H 11 )(THF) 2 ], which can also be obtained by reaction of [Er(η 5 -C 9 H 6 SiMe 2 C 2 -B 10 H 11 )Cl 2 (THF) 3 ] with potassium metal in THF (Scheme 6). 74 The isopropylidene-bridged erbium complex [Er(η 5 :η 6 -C 5 H 4 CMe 2 C 2 B 10 H 11 )(THF) 2 ] was obtained by the reduction method and characterized by X-ray crystallography. Excess sodium in THF afforded [{Er(η 5 :η 7 -C 5 H 4 CMe 2 C 2 B 10 H 11 )} 2 {Na 4 (THF) 9 ] x , which contains an η 7 -bonded arachno-type [C 2 B 10 H 11 ] 4-and which underwent substitution with ErCl 3 to give an unusual tetranuclear cluster [Er 2 (η 5 :η 7 -C 5 H 4 -CMe 2 C 2 B 10 H 11 )(THF) 3 (µ-Cl)] 2 .…”

3 Boron

“…In related studies, the corresponding indenyl ligands have been prepared and reactivity with selected lanthanide halides reported. 104,105 Exo-nido and closo lanthanacarboranes (Ln Sm, Yb) bearing the bis-benzyl substituted carborane (PhCH 2 ) 2 C 2 B 10 H 10 have been reported. 106 In another related study, a number of complexes containing erbium 107 coordinated to Z 7 -C 2 B 10 H 11 have also been described.…”

Half-pseudoferrocene cations from nucleophilic addition of o-carboranyl anions to the [(η6-mesitylene)2Fe]2+ dication

“…We have just recently entered the area of the [(Me n C 6 H 6−n ) 2 -Fe] 2+ dications (1) by exploring their reactions with the dicarbollide anion [7,8-C 2 B 9 H 11 ] 2− that generated a complete series of polymethylated arene ferradicarbaboranes [1-(η 6 -Me n C 6 H 6−n )-closo-1,2,3-FeC 2 B 9 H 11 ] with the number of arene methyls n = 1-6. 1,2 These reactions resulted in the displacement of one of the arene ligands 2 in 1 by the π-donating dicarbollide dianion and not in nucleophilic addition to the arene ring.…”

“…These types of reactions have been reported mostly for carbanions and other strong nucleophiles (for example, H − ) and are known to be strongly affected and restricted by the nature of the nucleophile, arene, and solvent used. 3 Although nucleophilic addition reactions of the [2-Me-1,2-C 2 B 10 H 10 ] − anion to the cyclopentadiene ring in [RuCl(Cp)(PPh 3 ) 2 ] and to the arene ring in [(η 6 -arene)Cr-(CO) 3 ] have been reported 4,5 no addition reactions of σ-bonding carborane anions to iron-complexed arenes have surprisingly been examined. Therefore we believe that this paper will represent the first successful attempt in the area of iron-arene chemistry.…”

“…Synthesis of [(η5 -mes-exo-6-{1,2-C 2 B 10 H 11 })Fe(η6 -mes)] + -(B 10 H 11 C 2 -C 2 B 10 H 12 ) − (3acCA) Solid [(η 6 -mes) 2 Fe](PF 6 ) 2 (1aPF 6 ) (530 mg, 1 mmol) was added in several portions to a solution of Li[1,2-C 2 B 10 H 11 ] (2a) (451 mg, 3 mmol) in THF (50 ml) at room temperature and the mixture was stirred 3 h. Further work up as in the preceding experiment gave 516 mg (71%) of orange 3acCA upon crystallization from a CH 2 Cl 2 solution onto the surface of which a layer of hexane was carefully added. Anal.…”