A contribution to the organometallic chemistry of uranium: tetra(allyl)uranium

Lugli, G.; Marconi, W.; Mazzei, A.; Paladino, N.; Pedretti, U.

doi:10.1016/s0020-1693(00)92490-3

Cited by 43 publications

(13 citation statements)

References 7 publications

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“…Reports on uranium allyl complexes first appeared in 1969 and 1974 on complexes formulated as (CH 2 CHCH 2 ) 3 UX (X = CH 2 CHCH 2 , 14 Cl, 15 Br, 15 I 15 ). These complexes were unstable above 253 K and were not structurally characterized by X-ray diffraction, but they were found to react with CO 2 16−18 and to be effective ethylene and butadiene polymerization catalysts when X was a halide.…”

Section: ■ Introductionmentioning

confidence: 99%

Synthesis and CO₂ Insertion Reactivity of Allyluranium Metallocene Complexes

Webster

Evans

2012

Organometallics

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The U 4+ metallocene allyl chloride complexes (C 5 Me 5 ) 2 U[η 3 -CH 2 C(R)CH 2 ]Cl (R = H, Me) can be synthesized by reaction of (C 5 Me 5 ) 2 UCl 2 with 1 equiv of the corresponding allyl Grignard reagents, [CH 2 C(R)CH 2 ]MgCl, in hydrocarbon solvents. Bis(allyl)uranium complexes can also be obtained in this manner using 2 equiv of the corresponding allyl Grignard, and X-ray crystallographic studies reveal the presence of both η 3 -and η 1

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Section: ■ Introductionmentioning

confidence: 99%

Synthesis and CO₂ Insertion Reactivity of Allyluranium Metallocene Complexes

Webster

Evans

2012

Organometallics

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“…The synthesis of σ-alkyl derivatives of the early actinide elements has long represented a synthetic challenge, due to the fact that the large size of the actinide metal center often imparts a degree of steric unsaturation to the isolated complex and can provide facile decomposition pathways, such as β-elimination, for alkyl-containing complexes. Therefore, it is not surprising that the earliest attempts to prepare homoleptic actinide alkyl complexes often led to the isolation of mixtures of thermally unstable products which proved difficult to characterize. , Numerous methodologies have subsequently been employed to overcome the problem of stabilizing homoleptic actinide σ-alkyl derivatives, including the preparation of anionic alkyl complexes which possess high coordination numbers at the metal center, the use of phosphine ligands to prepare base-stabilized alkyl complexes ThR 4 (Me 2 PCH 2 CH 2 PMe 2 ) (R = Me, CH 2 Ph), and the use of the sterically demanding bis(trimethylsilyl)methyl ligand to prepare the homoleptic uranium(III) alkyl derivative U[CH(SiMe 3 ) 2 ] 3 and cyclooctatetraenyl to produce steric saturation at the metal center and thus inhibit potential decomposition reactions.…”

Section: Introductionmentioning

confidence: 99%

Sterically Demanding Aryloxides as Supporting Ligands in Organoactinide Chemistry. Synthesis, Structural Characterization, and Reactivity of Th(O-2,6-t-Bu₂C₆H₃)₂(CH₂SiMe₃)₂ and Formation of the Trimeric Thorium Hydride Th₃H₆(O-2,6-t-Bu₂C₆H₃)₆

et al. 1996

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Reaction of ThBr 4 (THF) 4 with 2 equiv of KOAr (Ar ) 2,6-t-Bu 2 C 6 H 3 ) produces the bis-(aryloxide) complex ThBr 2 (OAr) 2 (THF) 2 (1) in 67% yield. Alkylation of 1 with 2 equiv of Me 3 SiCH 2 MgCl allows the isolation of Th(OAr) 2 (CH 2 SiMe 3 ) 2 (2) in 61% yield. Thermolysis of 2 (benzene, 60 °C, 36 h) in the presence of NEt 3 results in the formation of the cyclometalated ligand redistribution product Th(OC 6 H 3 -t-BuCMe 2 CH 2 )(OAr) 2 (3). Reaction of 2 with 1 equiv of 2,6-dimethylphenyl isocyanate leads to insertion into the Th-C bond to yield (ArO) 2 Th[OC(dNR)CH 2 SiMe 3 ](CH 2 SiMe 3 ) (4; R ) 2,6-Me 2 C 6 H 3 ). Aminolysis of 2 with 2 equiv of 2,6-diisopropylaniline allows the isolation of the bis(amido) species Th(OAr) 2 (NH-2,6-i-Pr 2 C 6 H 3 ) 2 (5) in 92% yield. 2 reacts with dihydrogen (1.5 atm) over a period of 7 days to form the trimeric dihydride complex Th 3 (µ 3 -H) 2 (µ 2 -H) 4 (OAr) 6 (6). In the presence of 1 equiv of [HNMe 2 Ph][B(C 6 F 5 ) 4 ], 2 catalyzes the hydrogenation of 1-hexene (N t ) 1 h -1 ), while 6 is found to be a single-component catalyst for the analogous process (N t ) 3 h -1 ). Complexes 1-6 have been characterized by 1 H NMR and IR spectroscopy, microanalysis, and, in the case of 2 and 6, by single-crystal X-ray diffraction studies. 2 comprises a pseudotetrahedral thorium metal center bearing two aryloxide and two alkyl ligands. The O-Th-O angle between the aryloxide ligands (119.2(4)°) is significantly larger than the C-Th-C angle (101.4(6)°). Th-O and Th-C distances average 2.137(11) and 2.462(18) Å, respectively, while Th-C-Si angles are 125.9(8) and 122.8(8)°. The alkyl groups of 2 also display a reduced C-H coupling constant (J CH ) 98 Hz), suggestive of R-agostic interaction between the methylene group and the Th metal center. 6 exhibits a triangular arrangement of three thorium metal centers, each bearing two terminal aryloxide ligands. Two sides of the trimetallic core (Th-Th distances 3.781(1) and 3.818(1) Å) are bridged by single µ 2 -hydride ligands, while the third side is bridged by two µ 2 -hydride ligands (Th-Th distance 3.588(1) Å). Each face of the trimer is capped by a µ 3 -hydride ligand to produce a structurally unique M 3 (µ 3 -X) 2 (µ 2 -X) 4 X 6 geometry. Th-(µ 2 -H) and Th-(µ 3 -H) distances lie in the ranges 2.0(1)-2.3(1) and 2.3(1)-2.6(1) Å, respectively, while Th-O distances range from 2.126(7) to 2.164-(7) Å.

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“…Influence of Electron-Accepting Additives. Starting from irallyl transition metal halides, enhanced catalytic activities may be achieved by adding various electron acceptors (e.g., metallic salts, iodine, derivatives of haloacetic acids and quinones as cocatalysts) (Dolgoplosk et al 1968, Golenko et al 1968, Lugli et al 1969, Mushina et al 1967, Yakovlev et al 1969b).…”

Section: Resultsmentioning

confidence: 99%

π-Allyl Type Polymerization

Dawans¹,

Teyssié²

1971

Product R&D

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He received his PhD degree from the University of Louvain (Belgium) with Professor G. Smets, and he studied as research associate of the University of Arizona (Tucson, USA) under Professor C. S. Marvel. His main research interests are stereospecific polymerization mechanisms and synthesis and properties of new polymers. Successively Assistant at the University of Louvain (Belgium) , Professor at Lovanium University (Congo), Research Associate at Brooklyn Polytechnic Institute (N. Y.), and Senior Chemist at the Institut Frangais du Petrole (Paris), Dr. Philippe Teyssie is now Professor of Organic Chemistry a the

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A contribution to the organometallic chemistry of uranium: tetra(allyl)uranium

Cited by 43 publications

References 7 publications

Synthesis and CO₂ Insertion Reactivity of Allyluranium Metallocene Complexes

Synthesis and CO₂ Insertion Reactivity of Allyluranium Metallocene Complexes

Sterically Demanding Aryloxides as Supporting Ligands in Organoactinide Chemistry. Synthesis, Structural Characterization, and Reactivity of Th(O-2,6-t-Bu₂C₆H₃)₂(CH₂SiMe₃)₂ and Formation of the Trimeric Thorium Hydride Th₃H₆(O-2,6-t-Bu₂C₆H₃)₆

π-Allyl Type Polymerization

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A contribution to the organometallic chemistry of uranium: tetra(allyl)uranium

Cited by 43 publications

References 7 publications

Synthesis and CO2 Insertion Reactivity of Allyluranium Metallocene Complexes

Synthesis and CO2 Insertion Reactivity of Allyluranium Metallocene Complexes

Sterically Demanding Aryloxides as Supporting Ligands in Organoactinide Chemistry. Synthesis, Structural Characterization, and Reactivity of Th(O-2,6-t-Bu2C6H3)2(CH2SiMe3)2 and Formation of the Trimeric Thorium Hydride Th3H6(O-2,6-t-Bu2C6H3)6

π-Allyl Type Polymerization

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Synthesis and CO₂ Insertion Reactivity of Allyluranium Metallocene Complexes

Synthesis and CO₂ Insertion Reactivity of Allyluranium Metallocene Complexes

Sterically Demanding Aryloxides as Supporting Ligands in Organoactinide Chemistry. Synthesis, Structural Characterization, and Reactivity of Th(O-2,6-t-Bu₂C₆H₃)₂(CH₂SiMe₃)₂ and Formation of the Trimeric Thorium Hydride Th₃H₆(O-2,6-t-Bu₂C₆H₃)₆