Synthetic Aspects of (C5H4SiMe3)3Ln Rare-Earth Chemistry: Formation of (C5H4SiMe3)3Lu via [(C5H4SiMe3)2Ln]+ Metallocene Precursors

Peterson, Jeffrey K.; MacDonald, Matthew R.; Evans, William J.

doi:10.1021/om400116d

Cited by 42 publications

(35 citation statements)

References 58 publications

(88 reference statements)

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“…[37] KCp'' was made analogously to KCp'. [35] [K(18-crown-6)(THF) 2 ][Cp'' 3 U],2 -K(18c6):I nag lovebox, addition of solid KC 8 (70 mg, 0.50 mmol) to av igorously stirred green solution of Cp'' 3 U( 204 mg, 0.236 mmol) and 18-crown-6 (68 mg, 0.26 mmol) in THF (3 mL) caused the mixture to immediately turn black. After stirring 4min, the reaction was filtered to remove black solids, presumably graphite, and the solvent was removed under reduced pressure.…”

Section: Methodsmentioning

confidence: 99%

Expanding the Chemistry of Molecular U²⁺ Complexes: Synthesis, Characterization, and Reactivity of the {[C₅H₃(SiMe₃)₂]₃U}⁻ Anion

Windorff

MacDonald

Meihaus

et al. 2015

Chemistry A European J

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124

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The synthesis of new molecular complexes of U2+ has been pursued to make comparisons in structure, physical properties, and reactivity with the first U2+ complex, [K(2.2.2‐cryptand)][Cp′3U], 1 (Cp′=C5H4SiMe3). Reduction of Cp′′3U [Cp′′=C5H3(SiMe3)2] with KC8 in the presence of 2.2.2‐cryptand or 18‐crown‐6 generates [K(2.2.2‐cryptand)][Cp′′3U], 2‐K(crypt), or [K(18‐crown‐6)(THF)2][Cp′′3U], 2‐K(18c6), respectively. The UV/Vis spectra of 2‐K and 1 are similar, and they are much more intense than those of U3+ analogues. Variable temperature magnetic susceptibility data for 1 and 2‐K(crypt) reveal lower room temperature χMT values relative to the experimental values for the 5f3 U3+ precursors. Stability studies monitored by UV/Vis spectroscopy show that 2‐K(crypt) and 2‐K(18c6) have t1/2 values of 20 and 15 h at room temperature, respectively, vs. 1.5 h for 1. Complex 2‐K(18c6) reacts with H2 or PhSiH3 to form the uranium hydride, [K(18‐crown‐6)(THF)2][Cp′′3UH], 3. Complexes 1 and 2‐K(18c6) both reduce cyclooctatetraene to form uranocene, (C8H8)2U, as well as the U3+ byproducts [K(2.2.2‐cryptand)][Cp′4U], 4, and Cp′′3U, respectively.

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Section: Methodsmentioning

confidence: 99%

Expanding the Chemistry of Molecular U²⁺ Complexes: Synthesis, Characterization, and Reactivity of the {[C₅H₃(SiMe₃)₂]₃U}⁻ Anion

Windorff

MacDonald

Meihaus

et al. 2015

Chemistry A European J

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124

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“…NMR solvents (Cambridge Isotope Laboratories) were dried over NaK/benzophenone, degassed by three freeze−pump−thaw cycles, and vacuum transferred prior to use. Anhydrous LnCl 3 (Ln = Y, La, Ce, Dy), 20 KCp′ (Cp′ = C 5 H 4 SiMe 3 ), 21 KC 8 , 22 Cp′ 3 Ln (Ln = Y, 2 La, 21 Reaction of 1-Ce with Naphthalene. In a glovebox, a solution of naphthalene (6 mg, 0.05 mmol) in THF (1 mL) was added to a stirred dark purple solution of [K(2.2.2-cryptand)][Cp′ 3 Ce]·THF, 1-Ce (90 mg, 0.087 mmol), in THF (2 mL).…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

Reactivity of the Ln²⁺ Complexes [K(2.2.2-cryptand)][(C₅H₄SiMe₃)₃Ln]: Reduction of Naphthalene and Biphenyl

2015

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The reductive capacity of the recently discovered Ln 2+ complexes [K(2.2.2-cryptand)][Cp′ 3 Ln], 1-Ln (Cp′ = C 5 H 4 SiMe 3 ; Ln = Y, La, Ce, Dy), has been probed by examining their reactions with aromatic hydrocarbons. [K-(2.2.2-cryptand)][Cp′ 3 Y], 1-Y, is capable of reducing naphthalene and forms a mixture of the naphthalenide dianion complex [K(2.2.2-cryptand)][Cp′ 2 Y(η 4 -C 10 H 8 )], 2-Y, as well as the ligand redistribution product [K(2.2.2-cryptand)][Cp′ 4 Y], 3-Y, and the cyclopentadienyl ligand salt [K(2.2.2-cryptand)]-[Cp′], 4. Naphthalene is reduced analogously by 1-La, 1-Ce, and 1-Dy. Each complex in the yttrium reaction was synthesized independently to confirm its identity in the mixture. Complex 2-Y was prepared from [Cp′ 2 Y(THF) 2 ]-[BPh 4 ], 5 (synthesized from [Et 3 NH][BPh 4 ] and Cp′ 3 Y), and K/naphthalene. Complex 3-Y was obtained by adding KCp′ to Cp′ 3 Y in the presence of 2.2.2-cryptand. [K(2.2.2-cryptand)][Cp′] was synthesized from 2.2.2-cryptand and KCp′. Each C 10 unit in the reduced naphthalene products, 2-Y, 2-La, 2-Ce, and 2-Dy, is bent with four carbon atoms of one ring oriented toward the metal, while the remaining six carbon atoms form a planar ring consistent with (η 4 -C 10 H 8 ) 2− coordination. In the solid state, 3-Y contains one η 1 -Cp′ ligand and three η 5 -Cp′ rings, whereas all four Cp′ rings in 3-La have η 5 -coordination. In the solid-state structure of 4, the (Cp′) − anion is not coordinated to potassium, which is encapsulated by the cryptand and located 7.063 Å from the ring centroid. Complex 1-Y also reduces biphenyl to form [K(2.2.2-cryptand)][Cp′ 2 Y(η 6 -C 6 H 5 Ph)], 6-Y, which contains a dianion with a planar aromatic phenyl ring as a substituent on a nonplanar η 6 -C 6 ring oriented toward the metal ion. ■ INTRODUCTIONRecently, the number of +2 ions available in the lanthanide series in soluble molecular complexes has been expanded from the traditional list of six, namely, Eu 2+ , Yb 2+ , Sm 2+ , Tm 2+ , Dy 2+ , and Nd 2+ , to the rest of the lanthanides except radioactive promethium via the potassium graphite reactions shown in Schemes 1 1 and 2. 2−4 The availability of these complexes allows the reaction chemistry of these new oxidation states to be investigated for the first time.A traditional way to characterize reducing agents too reactive for reproducible electrochemistry is to treat them with polycyclic hydrocarbons of known reduction potential. 5−8 This was initially used to characterize the reactivity 5 of (C 5 Me 5 ) 2 Sm 9 and subsequently used for NdI 2 6 and DyI 2 . 7 (C 5 Me 5 ) 2 Sm can reduce anthracene (−1.98 V vs SCE 10 ) to form [(C 5 Me 5 ) 2 Sm] 2 (μ-C 14 H 10 ), but it does not reduce naphthalene (−2.60 V vs SCE 10 ). 5 The stronger reductants, NdI 2 and DyI 2 , reduce naphthalene in 1,2-dimethoxyethane (DME) and THF to produce [NdI 2 (THF) 3 ] 2 (μ-C 10 H 8 ) 6 and (C 10 H 8 )DyI(DME) 2 , 7 respectively. Although other reduced naphthalene complexes of the rare earth ions are known, 8,11−18 their preparations involve either (a) initial...

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“…It was found that dinitrogen can be reduced by photochemical activation of the Ln 3+ mixed-ligand tris(cyclopentadienyl) 4 ], which was then allowed to react with KCp to produce Cp 3 Lu as a yellow microcrystalline solid in good yield (86%) (Scheme 84) [60].…”

Section: Cp 3 Ln and Cp 3 Lnl Compoundsmentioning

confidence: 99%

“…The reaction of LaCl 3 and KCp in improperly dried THF gave the mixed-ligand complex Cp 2 CpLa(THF), rather than the expected hydrolysis product, [Cp 2 La(-OH)] 2 . Scheme 85 summarizes these reactions [60].…”

Section: Cp 3 Ln and Cp 3 Lnl Compoundsmentioning

confidence: 99%

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Lanthanides and actinides: Annual survey of their organometallic chemistry covering the year 2013

Edelmann

2015

Coordination Chemistry Reviews

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Synthetic Aspects of (C₅H₄SiMe₃)₃Ln Rare-Earth Chemistry: Formation of (C₅H₄SiMe₃)₃Lu via [(C₅H₄SiMe₃)₂Ln]⁺ Metallocene Precursors

Cited by 42 publications

References 58 publications

Expanding the Chemistry of Molecular U²⁺ Complexes: Synthesis, Characterization, and Reactivity of the {[C₅H₃(SiMe₃)₂]₃U}⁻ Anion

Expanding the Chemistry of Molecular U²⁺ Complexes: Synthesis, Characterization, and Reactivity of the {[C₅H₃(SiMe₃)₂]₃U}⁻ Anion

Reactivity of the Ln²⁺ Complexes [K(2.2.2-cryptand)][(C₅H₄SiMe₃)₃Ln]: Reduction of Naphthalene and Biphenyl

Lanthanides and actinides: Annual survey of their organometallic chemistry covering the year 2013

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Synthetic Aspects of (C5H4SiMe3)3Ln Rare-Earth Chemistry: Formation of (C5H4SiMe3)3Lu via [(C5H4SiMe3)2Ln]+ Metallocene Precursors

Cited by 42 publications

References 58 publications

Expanding the Chemistry of Molecular U2+ Complexes: Synthesis, Characterization, and Reactivity of the {[C5H3(SiMe3)2]3U}− Anion

Expanding the Chemistry of Molecular U2+ Complexes: Synthesis, Characterization, and Reactivity of the {[C5H3(SiMe3)2]3U}− Anion

Reactivity of the Ln2+ Complexes [K(2.2.2-cryptand)][(C5H4SiMe3)3Ln]: Reduction of Naphthalene and Biphenyl

Lanthanides and actinides: Annual survey of their organometallic chemistry covering the year 2013

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Synthetic Aspects of (C₅H₄SiMe₃)₃Ln Rare-Earth Chemistry: Formation of (C₅H₄SiMe₃)₃Lu via [(C₅H₄SiMe₃)₂Ln]⁺ Metallocene Precursors

Expanding the Chemistry of Molecular U²⁺ Complexes: Synthesis, Characterization, and Reactivity of the {[C₅H₃(SiMe₃)₂]₃U}⁻ Anion

Expanding the Chemistry of Molecular U²⁺ Complexes: Synthesis, Characterization, and Reactivity of the {[C₅H₃(SiMe₃)₂]₃U}⁻ Anion

Reactivity of the Ln²⁺ Complexes [K(2.2.2-cryptand)][(C₅H₄SiMe₃)₃Ln]: Reduction of Naphthalene and Biphenyl