REACTIVITY OF DECAMETHYLSAMAROCENES WITH TRIALKYLALUMINUM REAGENTS INCLUDING THE STRUCTURE OF A BRIDGED ISOBUTYLALUMINUM COMPLEX, (C5Me5)2Sm[(μ-CH2CHMe2)2AI(CH2CHMe2)2]

Evans, William J.; Leman, John T.; Clark, Robert D.

doi:10.1515/mgmc.2000.23.3.163

Cited by 14 publications

(27 citation statements)

References 20 publications

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“…GC-MS of the organic byproducts of eq 2 revealed PhC(Et) 2 (OH) and PhC(Et)CHMe, both of which are consistent with attack of alkylaluminum reagents on carboxylates and (C 5 Me 5 ) 2 Sm(μ- i Bu) 2 Al i Bu 2 , have been definitively identified in the product mixtures.…”

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confidence: 68%

“…22 GC-MS of the organic byproducts of eq 2 revealed PhC(Et) 2 (OH) and PhC(Et)dCHMe, both of which are consistent with attack of alkylaluminum reagents on carboxylates. 23 Analogous reactions between [(C 5 Me 5 ) 2 Sm(µ-O 2 CPh)] 2 and AlMe 3 and Al i Bu 3 also form mixtures, but only the analogues of 1, namely [(C 5 Me 5 ) 2 Sm(µ-Me) 2 AlMe 2 ] n (n ) 1, 2) 24 and (C 5 Me 5 ) 2 Sm(µ-i Bu) 2 Al i Bu 2 , 25 have been definitively identified in the product mixtures.…”

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confidence: 99%

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An Ethyl Aluminum Oxide (EAO) Complex with μ-η¹:η²-Ethyl Coordination Derived from a Samarocene Carboxylate and Triethylaluminum

2005

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confidence: 68%

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An Ethyl Aluminum Oxide (EAO) Complex with μ-η¹:η²-Ethyl Coordination Derived from a Samarocene Carboxylate and Triethylaluminum

2005

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“…Although the reactivity of TMA toward various divalent ytterbium and samarium compounds has been examined, aryloxide derivatives apparently escaped that attention. For example, YbCp* 2 (THF) 2 simply forms the organoaluminum adduct complex Cp* 2 Yb(μ-Et)AlEt 2 (THF), while samarocene(II) complexes reduce AlR 3 compounds to yield samarocene(III) tetraalkylaluminate complexes. , Depending on the amount of AlR 3 reagent, silylamide complexes of Yb(II) and Sm(II) form bis-AlR 3 adducts or bis(tetraalkylaluminate) complexes of composition Ln[N(SiMe 3 ) 2 ] 2 (AlMe 3 ) 2 17b and [Ln(AlR 4 ) 2 ] n , respectively.…”

Section: Resultsmentioning

confidence: 99%

Reactivity of Trimethylaluminum with Lanthanide Aryloxides: Adduct and Tetramethylaluminate Formation

et al. 2003

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The reaction of various highly substituted lanthanide(III) and -(II) aryloxide complexes with trimethylaluminum (TMA) was investigated. The solvent-free, π-arene-bridged dimers [Ln(OAr i Pr,H)3]2, derived from the ortho-iPr2-substituted aryloxide ligand OC6H3 i Pr2-2,6, form bis-TMA adduct complexes, Ln(OAr i Pr,H)3(AlMe3)2, for the metal centers yttrium, samarium, and lanthanum. Homoleptic monomeric Ln(OAr)3, featuring a large La center and sterically bulkier ortho-tBu2-substituted aryloxide ligands, afford the mono-TMA adducts La(OAr t Bu,R)3(AlMe3) (R = H, Me). The hetero-bridged moieties “Ln(μ-OAr)(μ-Me)Al” of these adduct complexes are rigid in solution, while at ambient temperature the exchange of bridging and terminal aluminum methyl groups is fast on the NMR time scale. Monomeric Ln(OAr t Bu,R)3 (R = H, Me, tBu) of the smaller rare-earth-metal centers yttrium and lutetium react with TMA to give mono(tetramethylaluminate) complexes of the type (Ar t Bu,RO)2Ln[(μ-Me)2AlMe2]. The heteroleptic Cp*-supported complex (C5Me5)Y(OAr t Bu,H)2 also produced a tetramethylaluminate complex, namely (C5Me5)Y(OAr t Bu,H)[(μ-Me)2AlMe2], in the TMA reaction. The solvated aryloxide complexes Ln(OAr)2(THF) x (x = 1, 2), featuring the divalent rare-earth-metal centers ytterbium and samarium, yield the bis-TMA adduct complexes Ln[(μ-OAr t Bu,R)(μ-Me)AlMe2]2. However, it was found that the generation of homoleptic hexane-insoluble [Ln(AlMe4)2] n is an important reaction pathway governed by the size (oxophilicity) of the metal center (Yb ≫ Sm), the amount of TMA, the reaction period, and the substituents of the aryloxide ligand (OAr i Pr,H ≫ OAr t Bu,H > OAr t Bu,Me ≫ OAr t Bu, t Bu). For the Ln(III) aryloxide complexes, peralkylated complexes Ln(AlMe4)3 were detected only in the presence of the least bulky ligand, OAr i Pr,H. Various mechanistic scenarios are depicted on the basis of the rare-earth-metal species identified, including byproducts such as [Me2Al(μ-OAr)]2, and of the interactivity of rare-earth alkoxide complexes with trialkylaluminum compounds known from the literature. The complexes Y(OC6H3 i Pr2-2,6)[(μ-OC6H3 i Pr2-2,6)(μ-Me)AlMe2]2 and Ln(OC6H3 t Bu2-2,6)2[(μ-Me)2AlMe2] (Ln = Y, Lu) have been characterized by X-ray diffraction structure determinations.

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“…A similar situation is observed between (C 5 Me 5 ) 2 Sm(µ-Et) 2 AlEt 2 (Sm-C(µ-Et) ) 2.662(4) Å av) 36 and (C 5 Me 5 ) 2 Sm-(µ-i Bu) 2 Al( i Bu) 2 (Sm-C(µ-i Bu) ) 2.745(1) Å). 37 [(C 5 Me 5 ) 2 Y(µ-Cl)(µ-Me)AlMe 2 ] 2 , 7. The fact that the mixed bridging ligand chloro methyl complex 7 crystallizes as a dimer vis-a `-vis the monomeric ethyl and isobutyl complexes (C 5 Me 5 ) 2 Y(µ-Cl)(µ-Et)AlEt 2 , 5, and (C 5 Me 5 ) 2 Y(µ-Cl)(µ-i Bu)Al( i Bu) 2 , 6, may reflect the facility with which a bridging methyl can form a nearly linear Ln-[µ-C(alkyl)]-Al connection.…”

Section: Structuralmentioning

confidence: 99%

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

et al. 2005

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The well-defined coordination environment of trivalent [(C5Me5)2Ln]+ complexes has been used to examine the reaction chemistry of the lanthanide carboxylate and R2AlCl (R = Me, Et, iBu) components used in the preparation of lanthanide-based diene polymerization catalysts. Each of the R2AlCl reagents can replace a carboxylate ligand with chloride in reactions with [(C5Me5)2Sm(O2CC6H5)]2, but instead of forming a simple chloride complex like [(C5Me5)2SmCl]3, bimetallic lanthanide aluminum dichloro complexes (C5Me5)2Sm(μ-Cl)2AlR2 are generated by ligand redistribution. These bis(chloride)-bridged complexes are also readily formed from the divalent precursor (C5Me5)2Sm(THF)2 and R2AlCl. However, the analogous reaction between (C5Me5)2Sm(THF)2 and Et3Al gives (C5Me5)2Sm(THF)(μ-η2-Et)AlEt3, which contains the first Ln(III)−(η2-Et) linkage, a coordination mode that differentiates Et from Me. To determine if mixed mono-chloride/alkyl-bridged (C5Me5)2Ln(μ-Cl)(μ-R)AlR2 complexes can be isolated, (C5Me5)2Y(μ-Cl)YCl(C5Me5)2 was reacted with R3Al. These reactions form [(C5Me5)2Y(μ-Cl)(μ-R)AlR2] x complexes, but again there is a differentiation on the basis of R: the Me complex is a dimer and the others are monomers. (C5Me5)2Y(μ-Cl)2AlR2 complexes were similarly prepared for comparison with the mixed ligand species and for additional Me, Et, and iBu comparisons.

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REACTIVITY OF DECAMETHYLSAMAROCENES WITH TRIALKYLALUMINUM REAGENTS INCLUDING THE STRUCTURE OF A BRIDGED ISOBUTYLALUMINUM COMPLEX, (C5Me5)2Sm[(μ-CH2CHMe2)2AI(CH2CHMe2)2]

Cited by 14 publications

References 20 publications

An Ethyl Aluminum Oxide (EAO) Complex with μ-η¹:η²-Ethyl Coordination Derived from a Samarocene Carboxylate and Triethylaluminum

An Ethyl Aluminum Oxide (EAO) Complex with μ-η¹:η²-Ethyl Coordination Derived from a Samarocene Carboxylate and Triethylaluminum

Reactivity of Trimethylaluminum with Lanthanide Aryloxides: Adduct and Tetramethylaluminate Formation

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

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REACTIVITY OF DECAMETHYLSAMAROCENES WITH TRIALKYLALUMINUM REAGENTS INCLUDING THE STRUCTURE OF A BRIDGED ISOBUTYLALUMINUM COMPLEX, (C5Me5)2Sm[(μ-CH2CHMe2)2AI(CH2CHMe2)2]

Cited by 14 publications

References 20 publications

An Ethyl Aluminum Oxide (EAO) Complex with μ-η1:η2-Ethyl Coordination Derived from a Samarocene Carboxylate and Triethylaluminum

An Ethyl Aluminum Oxide (EAO) Complex with μ-η1:η2-Ethyl Coordination Derived from a Samarocene Carboxylate and Triethylaluminum

Reactivity of Trimethylaluminum with Lanthanide Aryloxides: Adduct and Tetramethylaluminate Formation

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

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An Ethyl Aluminum Oxide (EAO) Complex with μ-η¹:η²-Ethyl Coordination Derived from a Samarocene Carboxylate and Triethylaluminum

An Ethyl Aluminum Oxide (EAO) Complex with μ-η¹:η²-Ethyl Coordination Derived from a Samarocene Carboxylate and Triethylaluminum