Rhenium(VII) Oxo−Alkyl Complexes:  Reductive and α-Elimination Reactions

1996 ◽  
Vol 15 (3) ◽  
pp. 1023-1032 ◽  
Author(s):  
Shiang Cai ◽  
David M. Hoffman ◽  
Derk A. Wierda
Keyword(s):  
Alkyl Complexes ◽  
Elimination Reactions

scholarly journals Ligand influence on intramolecular cyclometalation in bis(phosphinimine) rare earth alkyl complexes

2016 ◽  
Vol 94 (4) ◽  
pp. 330-341 ◽  
Author(s):  
Kevin R.D. Johnson ◽  
Breanne L. Kamenz ◽  
Paul G. Hayes
Keyword(s):  
Rare Earth ◽  
Kinetic Analysis ◽  
Ancillary Ligand ◽  
X Ray ◽  
X Ray Crystallography ◽  
Alkyl Complexes ◽  
Ortho Metalation ◽  
Elimination Reactions ◽  
Alkane Elimination

The synthesis and reactivity of two new bis(phosphinimine)carbazole ligands (PippN=PMe2)2DMC (HLA, 3) and (PippN=P(C4H8))2DMC (HLB, 10), where Pipp = para-isopropylphenyl and DMC = 3,6-dimethylcarbazole, are reported. Dialkyl lutetium complexes of 3 and 10 were prepared in the presence of DMAP and THF by reaction of the proteo ligands with the new trialkyl reagent, Lu(CH2SiMe3)3(DMAP)2 (4) as well as Lu(CH2SiMe3)3(THF)2. For both ligands 3 and 10, the resulting lutetium complexes were prone to intramolecular cyclometalative alkane elimination reactions whereby the location of cyclometalation was influenced by the identity of the ancillary ligand coordinated to the metal. For ligand 3, cyclometalation of two PMe2 groups generated the complex (LA-κ3N,κ2C)Lu(DMAP)2 (5), whereas ligand 10 resulted in the single ortho-metalation of a para-isopropylphenyl ring to afford (LB-κ3N,κC)Lu(CH2SiMe3) (12). When complexed with scandium, ligand 10 behaved differently; double cyclometalation of two phospholane moieties resulted in the species (LB-κ3N,κ2C)Sc (15). The nature of the cyclometalation reactivity of ligands 3 and 10 is supported by X-ray crystallography and kinetic analysis, respectively.

Synthesis and Characterisation of Two Lithium Tetramethylberyllate Salts and a Series of β-Diketiminato Beryllium Alkyl Complexes

2020 ◽  
Vol 73 (12) ◽  
pp. 1144
Author(s):  
Albert Paparo ◽  
Caspar N. de Bruin-Dickason ◽  
Cameron Jones
Keyword(s):  
Titration Method ◽  
Alkyl Complexes ◽  
Elimination Reactions ◽  
Synthetic Studies ◽  
Alkane Elimination

A safer route than that previously published for the synthesis of [BeI2(OEt2)2] has been developed. Reactions of beryllium dihalide complexes [BeX2(OEt2)2] (X=Br or I) with either LiMe or LiBun lead to mixtures of products, which have been shown to act as sources of ‘BeR2’ (R=Me or Bun) in previous synthetic studies. Here, a titration method has been developed to determine the quantity of metal alkyl residues in these ‘BeR2’ mixtures that are available for subsequent alkane elimination reactions. Treating ‘BeMe2’ mixtures with N,N,N′,N′-tetramethylethylenediamine (tmeda) gave two lithium tetramethylberyllate compounds, [{(tmeda)Li}2(μ-BeMe4)] and [{[(tmeda)Li](BeMe4)(μ-Li)}∞], which were crystallographically characterised. Treatment of insitu-generated ‘BeR2’ solutions with several β-diketimines (HC{C(Me)=NR}{=C(Me)N(H)R}, NacnacH, R=aryl or alkyl) yielded a series of β-diketiminato beryllium alkyl complexes, [(Nacnac)BeR], including the first chiral example of such a compound. Crystallographic studies of these reveal them to be monomeric, with planar three-coordinate beryllium centres.

Solvolytic reactions of empiric 3-methanesulfonyloxy-7-benzoyloxy-5β,6β-cyclopropanocholestanes

1986 ◽  
Vol 51 (2) ◽  
pp. 436-446 ◽  
Author(s):  
Ladislav Kohout ◽  
Vijay Kumar Sethi ◽  
Jaroslav Zajíček ◽  
Alexander Kasal
Keyword(s):  
Spectral Methods ◽  
Elimination Reactions

Acetolysis of 3-methanesulfonyloxy-7-benzoyloxy-5β,6β-cyclopropanocholestanes with various configurations in positions 3 and 7 is described and the products are assigned structure using spectral methods. The 7-substituted compounds show greater propensity to elimination reactions than the 7-unsubstituted ones.

Simple theoretical models for elimination reactions on polar catalysts; The reactivity of halogeno-, hydroxy-, amino- and mercaptopropane

1982 ◽  
Vol 47 (8) ◽  
pp. 2180-2189 ◽  
Author(s):  
Jiří Sedláček
Keyword(s):  
Theoretical Models ◽  
Molecular Orbitals ◽  
Localized Molecular Orbitals ◽  
Hydroxy Amino ◽  
Elimination Reactions ◽  
Simple Models

CNDO/2 calculations have been made for simple models of the adsorption of (CH3)2CHZ molecules (Z = Cl, OH, NH2, and SH) on the surface of polar catalysts. The results of these calculations and their interpretation by the method of configuration analysis in terms of uniformly localized molecular orbitals made it possible to explain satisfactorily a series of experimental facts. The mechanism and stereoselectivity of the reaction as well as reactivity trends for the series of the molecules studied are discussed.

scholarly journals Force-modulated reductive elimination from platinum(ii) diaryl complexes

2021 ◽  
Author(s):  
Yichen Yu ◽  
Chenxu Wang ◽  
Liqi Wang ◽  
Cai-Li Sun ◽  
Roman Boulatov ◽  
...  
Keyword(s):  
Transition State ◽  
Reductive Elimination ◽  
Mechanical Force ◽  
Elimination Reactions

The influence of mechanical force on the rates of model reductive elimination reactions depends on the structure of the force-transducing ligand and provides a measure of geometry changes upon reaching the transition state.

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