Lanthanide Metallocene Reactivity with Dialkyl Aluminum Chlorides: Modeling Reactions Used to Generate Isoprene Polymerization Catalysts

William J. Evans; Timothy M. Champagne; Dimitri Giarikos; Joseph W. Ziller

doi:10.1021/om049484o

Lanthanide Metallocene Reactivity with Dialkyl Aluminum Chlorides: Modeling Reactions Used to Generate Isoprene Polymerization Catalysts

William J. Evans
, Timothy M. Champagne
, Dimitri Giarikos
, Joseph W. Ziller

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

68 Scopus citations

Abstract

The well-defined coordination environment of trivalent [(C ₅ Me ₅ ) ₂ Ln] ⁺ complexes has been used to examine the reaction chemistry of the lanthanide carboxylate and R ₂ AlCl (R = Me, Et, ⁱ Bu) components used in the preparation of lanthanide-based diene polymerization catalysts. Each of the R ₂ AlCl reagents can replace a carboxylate ligand with chloride in reactions with [(C ₅ Me ₅ ) ₂ Sm(O ₂ CC ₆ H ₅ )] ₂ , but instead of forming a simple chloride complex like [(C ₅ Me ₅ ) ₂ SmCl] ₃ , bimetallic lanthanide aluminum dichloro complexes (C ₅ Me ₅ ) ₂ Sm(μ-Cl) ₂ AlR ₂ are generated by ligand redistribution. These bis(chloride)-bridged complexes are also readily formed from the divalent precursor (C ₅ Me ₅ ) ₂ Sm(THF) ₂ and R ₂ AlCl. However, the analogous reaction between (C ₅ Me ₅ ) ₂ Sm(THF) ₂ and Et ₃ Al gives (C ₅ Me ₅ ) ₂ Sm(THF)(μ-η ² -Et)AlEt ₃ , which contains the first Ln(III)−(η ² -Et) linkage, a coordination mode that differentiates Et from Me. To determine if mixed mono-chloride/alkyl-bridged (C ₅ Me ₅ ) ₂ Ln(μ-Cl)(μ-R)AlR ₂ complexes can be isolated, (C ₅ Me ₅ ) ₂ Y(μ-Cl)YCl(C ₅ Me ₅ ) ₂ was reacted with R ₃ Al. These reactions form [(C ₅ Me ₅ ) ₂ Y(μ-Cl)(μ-R)AlR ₂ ] _x complexes, but again there is a differentiation on the basis of R: the Me complex is a dimer and the others are monomers. (C ₅ Me ₅ ) ₂ Y(μ-Cl) ₂ AlR ₂ complexes were similarly prepared for comparison with the mixed ligand species and for additional Me, Et, and ⁱ Bu comparisons.

Original language	American English
Pages (from-to)	570-579
Number of pages	10
Journal	Organometallics
Volume	24
Issue number	4
DOIs	https://doi.org/10.1021/om049484o https://doi.org/10.1021/om049484o
State	Published - Feb 1 2005
Externally published	Yes

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Physical and Theoretical Chemistry
Organic Chemistry
Inorganic Chemistry

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Chemistry

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@article{76448b22d05444baa49ad7da912555d7,

title = "Lanthanide Metallocene Reactivity with Dialkyl Aluminum Chlorides: Modeling Reactions Used to Generate Isoprene Polymerization Catalysts",

abstract = " The well-defined coordination environment of trivalent [(C 5 Me 5 ) 2 Ln] + complexes has been used to examine the reaction chemistry of the lanthanide carboxylate and R 2 AlCl (R = Me, Et, i Bu) components used in the preparation of lanthanide-based diene polymerization catalysts. Each of the R 2 AlCl reagents can replace a carboxylate ligand with chloride in reactions with [(C 5 Me 5 ) 2 Sm(O 2 CC 6 H 5 )] 2 , but instead of forming a simple chloride complex like [(C 5 Me 5 ) 2 SmCl] 3 , bimetallic lanthanide aluminum dichloro complexes (C 5 Me 5 ) 2 Sm(μ-Cl) 2 AlR 2 are generated by ligand redistribution. These bis(chloride)-bridged complexes are also readily formed from the divalent precursor (C 5 Me 5 ) 2 Sm(THF) 2 and R 2 AlCl. However, the analogous reaction between (C 5 Me 5 ) 2 Sm(THF) 2 and Et 3 Al gives (C 5 Me 5 ) 2 Sm(THF)(μ-η 2 -Et)AlEt 3 , which contains the first Ln(III)−(η 2 -Et) linkage, a coordination mode that differentiates Et from Me. To determine if mixed mono-chloride/alkyl-bridged (C 5 Me 5 ) 2 Ln(μ-Cl)(μ-R)AlR 2 complexes can be isolated, (C 5 Me 5 ) 2 Y(μ-Cl)YCl(C 5 Me 5 ) 2 was reacted with R 3 Al. These reactions form [(C 5 Me 5 ) 2 Y(μ-Cl)(μ-R)AlR 2 ] x complexes, but again there is a differentiation on the basis of R: the Me complex is a dimer and the others are monomers. (C 5 Me 5 ) 2 Y(μ-Cl) 2 AlR 2 complexes were similarly prepared for comparison with the mixed ligand species and for additional Me, Et, and i Bu comparisons.",

author = "Evans, \{William J.\} and Champagne, \{Timothy M.\} and Dimitri Giarikos and Ziller, \{Joseph W.\}",

year = "2005",

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doi = "10.1021/om049484o",

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pages = "570--579",

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T1 - Lanthanide Metallocene Reactivity with Dialkyl Aluminum Chlorides: Modeling Reactions Used to Generate Isoprene Polymerization Catalysts

AU - Evans, William J.

AU - Champagne, Timothy M.

AU - Giarikos, Dimitri

AU - Ziller, Joseph W.

PY - 2005/2/1

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N2 - The well-defined coordination environment of trivalent [(C 5 Me 5 ) 2 Ln] + complexes has been used to examine the reaction chemistry of the lanthanide carboxylate and R 2 AlCl (R = Me, Et, i Bu) components used in the preparation of lanthanide-based diene polymerization catalysts. Each of the R 2 AlCl reagents can replace a carboxylate ligand with chloride in reactions with [(C 5 Me 5 ) 2 Sm(O 2 CC 6 H 5 )] 2 , but instead of forming a simple chloride complex like [(C 5 Me 5 ) 2 SmCl] 3 , bimetallic lanthanide aluminum dichloro complexes (C 5 Me 5 ) 2 Sm(μ-Cl) 2 AlR 2 are generated by ligand redistribution. These bis(chloride)-bridged complexes are also readily formed from the divalent precursor (C 5 Me 5 ) 2 Sm(THF) 2 and R 2 AlCl. However, the analogous reaction between (C 5 Me 5 ) 2 Sm(THF) 2 and Et 3 Al gives (C 5 Me 5 ) 2 Sm(THF)(μ-η 2 -Et)AlEt 3 , which contains the first Ln(III)−(η 2 -Et) linkage, a coordination mode that differentiates Et from Me. To determine if mixed mono-chloride/alkyl-bridged (C 5 Me 5 ) 2 Ln(μ-Cl)(μ-R)AlR 2 complexes can be isolated, (C 5 Me 5 ) 2 Y(μ-Cl)YCl(C 5 Me 5 ) 2 was reacted with R 3 Al. These reactions form [(C 5 Me 5 ) 2 Y(μ-Cl)(μ-R)AlR 2 ] x complexes, but again there is a differentiation on the basis of R: the Me complex is a dimer and the others are monomers. (C 5 Me 5 ) 2 Y(μ-Cl) 2 AlR 2 complexes were similarly prepared for comparison with the mixed ligand species and for additional Me, Et, and i Bu comparisons.

AB - The well-defined coordination environment of trivalent [(C 5 Me 5 ) 2 Ln] + complexes has been used to examine the reaction chemistry of the lanthanide carboxylate and R 2 AlCl (R = Me, Et, i Bu) components used in the preparation of lanthanide-based diene polymerization catalysts. Each of the R 2 AlCl reagents can replace a carboxylate ligand with chloride in reactions with [(C 5 Me 5 ) 2 Sm(O 2 CC 6 H 5 )] 2 , but instead of forming a simple chloride complex like [(C 5 Me 5 ) 2 SmCl] 3 , bimetallic lanthanide aluminum dichloro complexes (C 5 Me 5 ) 2 Sm(μ-Cl) 2 AlR 2 are generated by ligand redistribution. These bis(chloride)-bridged complexes are also readily formed from the divalent precursor (C 5 Me 5 ) 2 Sm(THF) 2 and R 2 AlCl. However, the analogous reaction between (C 5 Me 5 ) 2 Sm(THF) 2 and Et 3 Al gives (C 5 Me 5 ) 2 Sm(THF)(μ-η 2 -Et)AlEt 3 , which contains the first Ln(III)−(η 2 -Et) linkage, a coordination mode that differentiates Et from Me. To determine if mixed mono-chloride/alkyl-bridged (C 5 Me 5 ) 2 Ln(μ-Cl)(μ-R)AlR 2 complexes can be isolated, (C 5 Me 5 ) 2 Y(μ-Cl)YCl(C 5 Me 5 ) 2 was reacted with R 3 Al. These reactions form [(C 5 Me 5 ) 2 Y(μ-Cl)(μ-R)AlR 2 ] x complexes, but again there is a differentiation on the basis of R: the Me complex is a dimer and the others are monomers. (C 5 Me 5 ) 2 Y(μ-Cl) 2 AlR 2 complexes were similarly prepared for comparison with the mixed ligand species and for additional Me, Et, and i Bu comparisons.

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U2 - 10.1021/om049484o

DO - 10.1021/om049484o

M3 - Article

SN - 0276-7333

VL - 24

SP - 570

EP - 579

JO - Organometallics

JF - Organometallics

IS - 4

ER -

Lanthanide Metallocene Reactivity with Dialkyl Aluminum Chlorides: Modeling Reactions Used to Generate Isoprene Polymerization Catalysts

Abstract

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