Lanthanoid Pseudo-Grignard Reagents: A Major Untapped Resource

Safaa H. Ali; Glen B. Deacon; Peter C. Junk; Shima Hamidi; Michal Wiecko; Jun Wang

doi:10.1002/chem.201704383

Lanthanoid Pseudo-Grignard Reagents: A Major Untapped Resource

Safaa H. Ali
, Glen B. Deacon
, Peter C. Junk
, Shima Hamidi
, Michal Wiecko
, Jun Wang

School of Chemistry

Research output: Contribution to journal › Article › Research › peer-review

31 Citations (Scopus)

Abstract

Pseudo-Grignard reagents PhLnI (Ln=Yb, Eu), readily prepared by the oxidative addition of iodobenzene to ytterbium or europium metal at −78 °C in tetrahydrofuran (THF) or 1,2-dimethoxyethane (DME), react with a range of bulky N,N′-bis(aryl)formamidines to generate an extensive series of Ln^II or more rarely Ln^III complexes, namely [Eu(DippForm)I(thf)₄]⋅thf (1), [{EuI₂(dme)₂}₂] (2), [Eu(XylForm)I(dme)₂]⋅0.5 dme (3 a), [Eu(XylForm)I(dme)(μ-dme)]_n (3 b), [{Eu(XylForm)I(μ-OH)(thf)₂}₂] (4), [Yb(DippForm)I(thf)₃]⋅thf (5 a), [Yb(DippForm)I₂(thf)₃]⋅2 thf (5 b), [{Yb(MesForm)I(thf)₂}₂] (6), [{Yb(XylForm)I(thf)₂}₂] (7 a), and [Yb(XylForm)₂I(dme)]⋅dme (7 b) {(Form=ArNCHNAr; XylForm (Ar=2,6-Me₂C₆H₃), MesForm (Ar=2,4,6-Me₃C₆H₂), DippForm (Ar=2,6-iPr₂C₆H₃)}. Reaction of PhEuI and MesFormH in DME consistently gave 2, and reaction with XylFormH in THF gave 4. Europium complexes 1 and 3 a are seven-coordinate divalent monomers, whilst 3 b is a seven-coordinate dme-bridged polymer. Complex 5 a of the smaller Yb^II is a six-coordinate monomer, but the related 6 and 7 a are six-coordinate iodide-bridged dimers. 4 is a trivalent seven-coordinate hydroxide-bridged dimer, whereas complexes 5 b and 7 b are seven-coordinate monomeric Yb^III derivatives. A characteristic structural feature is that iodide ligands are cisoid to the formamidinate ligand. To illustrate the synthetic scope of the pseudo-Grignard reagents, [Yb(Ph₂pz)I(thf)₄] (Ph₂pz=3,5-diphenylpyrazolate) was oxidised with 1,2-diiodoethane to afford seven-coordinate monomeric pyrazolato-ytterbium(III) iodide [Yb(Ph₂Pz)I₂(thf)₃] (8) in high yield, whilst metathesis between [Yb(Ph₂pz)I(thf)₄] and NaCp (Cp=C₅H₅) gave [Yb(C₅H₅)(Ph₂pz)(thf)]_n (9), a nine-coordinate η⁵:η⁵-Cp-bridged coordination polymer. Reaction of the pseudo-Grignard reagent MeYbI with KN(SiMe₃)₂ gave [K(dme)₄][Yb{N(SiMe₃)₂}₃] (10) with a charge-separated three-coordinate homoleptic [Yb{N(SiMe₃)₂}₃]⁻ anion, a complex that could be obtained in high yield by deliberate synthesis from YbI₂ and KN(SiMe₃)₂ in DME.

Original language	English
Pages (from-to)	230-242
Number of pages	13
Journal	Chemistry - A European Journal
Volume	24
Issue number	1
DOIs	https://doi.org/10.1002/chem.201704383
Publication status	Published - 2 Jan 2018

Keywords

europium
formamidines
LnLX-type complexes
organolanthanoid complexes
X-ray diffraction
ytterbium

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10.1002/chem.201704383

257365171-oaFinal published version, 2.14 MB

Cite this

@article{e80756f95e3a4b4bafb0b9a2a4de4851,

title = "Lanthanoid Pseudo-Grignard Reagents: A Major Untapped Resource",

abstract = "Pseudo-Grignard reagents PhLnI (Ln=Yb, Eu), readily prepared by the oxidative addition of iodobenzene to ytterbium or europium metal at −78 °C in tetrahydrofuran (THF) or 1,2-dimethoxyethane (DME), react with a range of bulky N,N′-bis(aryl)formamidines to generate an extensive series of LnII or more rarely LnIII complexes, namely [Eu(DippForm)I(thf)4]⋅thf (1), [\{EuI2(dme)2\}2] (2), [Eu(XylForm)I(dme)2]⋅0.5 dme (3 a), [Eu(XylForm)I(dme)(μ-dme)]n (3 b), [\{Eu(XylForm)I(μ-OH)(thf)2\}2] (4), [Yb(DippForm)I(thf)3]⋅thf (5 a), [Yb(DippForm)I2(thf)3]⋅2 thf (5 b), [\{Yb(MesForm)I(thf)2\}2] (6), [\{Yb(XylForm)I(thf)2\}2] (7 a), and [Yb(XylForm)2I(dme)]⋅dme (7 b) \{(Form=ArNCHNAr; XylForm (Ar=2,6-Me2C6H3), MesForm (Ar=2,4,6-Me3C6H2), DippForm (Ar=2,6-iPr2C6H3)\}. Reaction of PhEuI and MesFormH in DME consistently gave 2, and reaction with XylFormH in THF gave 4. Europium complexes 1 and 3 a are seven-coordinate divalent monomers, whilst 3 b is a seven-coordinate dme-bridged polymer. Complex 5 a of the smaller YbII is a six-coordinate monomer, but the related 6 and 7 a are six-coordinate iodide-bridged dimers. 4 is a trivalent seven-coordinate hydroxide-bridged dimer, whereas complexes 5 b and 7 b are seven-coordinate monomeric YbIII derivatives. A characteristic structural feature is that iodide ligands are cisoid to the formamidinate ligand. To illustrate the synthetic scope of the pseudo-Grignard reagents, [Yb(Ph2pz)I(thf)4] (Ph2pz=3,5-diphenylpyrazolate) was oxidised with 1,2-diiodoethane to afford seven-coordinate monomeric pyrazolato-ytterbium(III) iodide [Yb(Ph2Pz)I2(thf)3] (8) in high yield, whilst metathesis between [Yb(Ph2pz)I(thf)4] and NaCp (Cp=C5H5) gave [Yb(C5H5)(Ph2pz)(thf)]n (9), a nine-coordinate η5:η5-Cp-bridged coordination polymer. Reaction of the pseudo-Grignard reagent MeYbI with KN(SiMe3)2 gave [K(dme)4][Yb\{N(SiMe3)2\}3] (10) with a charge-separated three-coordinate homoleptic [Yb\{N(SiMe3)2\}3]− anion, a complex that could be obtained in high yield by deliberate synthesis from YbI2 and KN(SiMe3)2 in DME.",

keywords = "europium, formamidines, LnLX-type complexes, organolanthanoid complexes, X-ray diffraction, ytterbium",

author = "Ali, \{Safaa H.\} and Deacon, \{Glen B.\} and Junk, \{Peter C.\} and Shima Hamidi and Michal Wiecko and Jun Wang",

year = "2018",

month = jan,

day = "2",

doi = "10.1002/chem.201704383",

language = "English",

volume = "24",

pages = "230--242",

journal = "Chemistry - A European Journal",

issn = "0947-6539",

publisher = "Wiley-VCH Verlag GmbH \& Co. KGaA",

number = "1",

}

TY - JOUR

T1 - Lanthanoid Pseudo-Grignard Reagents

T2 - A Major Untapped Resource

AU - Ali, Safaa H.

AU - Deacon, Glen B.

AU - Junk, Peter C.

AU - Hamidi, Shima

AU - Wiecko, Michal

AU - Wang, Jun

PY - 2018/1/2

Y1 - 2018/1/2

N2 - Pseudo-Grignard reagents PhLnI (Ln=Yb, Eu), readily prepared by the oxidative addition of iodobenzene to ytterbium or europium metal at −78 °C in tetrahydrofuran (THF) or 1,2-dimethoxyethane (DME), react with a range of bulky N,N′-bis(aryl)formamidines to generate an extensive series of LnII or more rarely LnIII complexes, namely [Eu(DippForm)I(thf)4]⋅thf (1), [{EuI2(dme)2}2] (2), [Eu(XylForm)I(dme)2]⋅0.5 dme (3 a), [Eu(XylForm)I(dme)(μ-dme)]n (3 b), [{Eu(XylForm)I(μ-OH)(thf)2}2] (4), [Yb(DippForm)I(thf)3]⋅thf (5 a), [Yb(DippForm)I2(thf)3]⋅2 thf (5 b), [{Yb(MesForm)I(thf)2}2] (6), [{Yb(XylForm)I(thf)2}2] (7 a), and [Yb(XylForm)2I(dme)]⋅dme (7 b) {(Form=ArNCHNAr; XylForm (Ar=2,6-Me2C6H3), MesForm (Ar=2,4,6-Me3C6H2), DippForm (Ar=2,6-iPr2C6H3)}. Reaction of PhEuI and MesFormH in DME consistently gave 2, and reaction with XylFormH in THF gave 4. Europium complexes 1 and 3 a are seven-coordinate divalent monomers, whilst 3 b is a seven-coordinate dme-bridged polymer. Complex 5 a of the smaller YbII is a six-coordinate monomer, but the related 6 and 7 a are six-coordinate iodide-bridged dimers. 4 is a trivalent seven-coordinate hydroxide-bridged dimer, whereas complexes 5 b and 7 b are seven-coordinate monomeric YbIII derivatives. A characteristic structural feature is that iodide ligands are cisoid to the formamidinate ligand. To illustrate the synthetic scope of the pseudo-Grignard reagents, [Yb(Ph2pz)I(thf)4] (Ph2pz=3,5-diphenylpyrazolate) was oxidised with 1,2-diiodoethane to afford seven-coordinate monomeric pyrazolato-ytterbium(III) iodide [Yb(Ph2Pz)I2(thf)3] (8) in high yield, whilst metathesis between [Yb(Ph2pz)I(thf)4] and NaCp (Cp=C5H5) gave [Yb(C5H5)(Ph2pz)(thf)]n (9), a nine-coordinate η5:η5-Cp-bridged coordination polymer. Reaction of the pseudo-Grignard reagent MeYbI with KN(SiMe3)2 gave [K(dme)4][Yb{N(SiMe3)2}3] (10) with a charge-separated three-coordinate homoleptic [Yb{N(SiMe3)2}3]− anion, a complex that could be obtained in high yield by deliberate synthesis from YbI2 and KN(SiMe3)2 in DME.

AB - Pseudo-Grignard reagents PhLnI (Ln=Yb, Eu), readily prepared by the oxidative addition of iodobenzene to ytterbium or europium metal at −78 °C in tetrahydrofuran (THF) or 1,2-dimethoxyethane (DME), react with a range of bulky N,N′-bis(aryl)formamidines to generate an extensive series of LnII or more rarely LnIII complexes, namely [Eu(DippForm)I(thf)4]⋅thf (1), [{EuI2(dme)2}2] (2), [Eu(XylForm)I(dme)2]⋅0.5 dme (3 a), [Eu(XylForm)I(dme)(μ-dme)]n (3 b), [{Eu(XylForm)I(μ-OH)(thf)2}2] (4), [Yb(DippForm)I(thf)3]⋅thf (5 a), [Yb(DippForm)I2(thf)3]⋅2 thf (5 b), [{Yb(MesForm)I(thf)2}2] (6), [{Yb(XylForm)I(thf)2}2] (7 a), and [Yb(XylForm)2I(dme)]⋅dme (7 b) {(Form=ArNCHNAr; XylForm (Ar=2,6-Me2C6H3), MesForm (Ar=2,4,6-Me3C6H2), DippForm (Ar=2,6-iPr2C6H3)}. Reaction of PhEuI and MesFormH in DME consistently gave 2, and reaction with XylFormH in THF gave 4. Europium complexes 1 and 3 a are seven-coordinate divalent monomers, whilst 3 b is a seven-coordinate dme-bridged polymer. Complex 5 a of the smaller YbII is a six-coordinate monomer, but the related 6 and 7 a are six-coordinate iodide-bridged dimers. 4 is a trivalent seven-coordinate hydroxide-bridged dimer, whereas complexes 5 b and 7 b are seven-coordinate monomeric YbIII derivatives. A characteristic structural feature is that iodide ligands are cisoid to the formamidinate ligand. To illustrate the synthetic scope of the pseudo-Grignard reagents, [Yb(Ph2pz)I(thf)4] (Ph2pz=3,5-diphenylpyrazolate) was oxidised with 1,2-diiodoethane to afford seven-coordinate monomeric pyrazolato-ytterbium(III) iodide [Yb(Ph2Pz)I2(thf)3] (8) in high yield, whilst metathesis between [Yb(Ph2pz)I(thf)4] and NaCp (Cp=C5H5) gave [Yb(C5H5)(Ph2pz)(thf)]n (9), a nine-coordinate η5:η5-Cp-bridged coordination polymer. Reaction of the pseudo-Grignard reagent MeYbI with KN(SiMe3)2 gave [K(dme)4][Yb{N(SiMe3)2}3] (10) with a charge-separated three-coordinate homoleptic [Yb{N(SiMe3)2}3]− anion, a complex that could be obtained in high yield by deliberate synthesis from YbI2 and KN(SiMe3)2 in DME.

KW - europium

KW - formamidines

KW - LnLX-type complexes

KW - organolanthanoid complexes

KW - X-ray diffraction

KW - ytterbium

UR - https://www.scopus.com/pages/publications/85037636939

U2 - 10.1002/chem.201704383

DO - 10.1002/chem.201704383

M3 - Article

AN - SCOPUS:85037636939

SN - 0947-6539

VL - 24

SP - 230

EP - 242

JO - Chemistry - A European Journal

JF - Chemistry - A European Journal

IS - 1

ER -

Lanthanoid Pseudo-Grignard Reagents: A Major Untapped Resource

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Keywords

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Reactive metal-organics embracing the rare earth and alkaline earth metals

Advancing the chemistry of topical Rare Earth metals

Australian Synchrotron

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Lanthanoid Pseudo-Grignard Reagents: A Major Untapped Resource

Abstract

Keywords

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Projects

Reactive metal-organics embracing the rare earth and alkaline earth metals

Advancing the chemistry of topical Rare Earth metals

Equipment

Australian Synchrotron

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