Ta(V) complexes of a bulky amine tris(phenolate) ligand: steric inhibition vs. chelate effect

Groysman, Stanislav; Segal, Sofia; Goldberg, Israel; Kol, Moshe; Goldschmidt, Zeev

doi:10.1016/j.inoche.2004.06.003

Cited by 25 publications

(19 citation statements)

References 13 publications

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“…Indeed, this barrier is the highest energy barrier along the entire route B (Figure 6). A considerably lower barrier for the MeNC coordination (5.5 kcal mol −1 ) was calculated in [calix [4](OMe) 2 (O) 2 ZrMe 2 ]. 26 The outcome of the addition step is the intermediate 1B_iso, which is placed 14.1 kcal mol −1 above the reactants (Figure 7).…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…The DFT molecular dynamics study of the methyl isocyanide migratory insertion into the Zr−C Me bond of [[calix [4]-(OMe) 2 (O) 2 ZrMe 2 ] also suggested the initial formation of a transient κ 1 -iminoacyl species, with a formed C Me −C iso bond and still a long Zr−N bond. 26 We were not able to find the transition state connecting κ 1 -and κ 2 -iminoacyl isomers.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…12 Such migrations have been reported for most of the early transition metals, and they lead to the formation of κ 2 -C,N-iminoacyl ligands, which are prone to experience further transformations. Regarding systems with multidentate phenolate ligands, the migratory insertion of isocyanides into zirconium 13 and vanadium−carbon bonds 14 anchored to a calix [4]arene moiety has been explored. Migratory insertion of isocyanides into tantalum−carbon bonds of cyclopentadienyl 15−17 and imido 18,19 tantalum complexes has been investigated.…”

Section: ■ Introductionmentioning

confidence: 99%

“…The mechanism of the migratory insertion of isocyanides into metal−carbon bonds has been theoretically studied by means of DFT calculations in simple model systems such as [MoCp 2 (CH 3 )(CNH)] +24 and [(Ind)Ti(NH 2 )(CH 3 )-(CNH)]. 25 The migration in systems with multidentate ligands has been investigated by means of both static and dynamic density functional calculations in the zirconium dimethyl unit anchored to a calix [4]arene moiety. 13,26 Methyl isocyanide migratory insertion forms sequentially the methyl-κ 2 -C,Niminoacyl and the κ 2 -bound imine.…”

Section: ■ Introductionmentioning

confidence: 99%

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Rearrangement of Tridentate [OSO]-Type Ligands and Migratory Insertion Reaction Mechanisms in Cyclopentadienyl Tantalum Complexes

et al. 2012

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The mechanism of the isocyanide migratory insertion into the metal–carbon bond of monocylopentadienyltantalum dimethyl derivatives with [OSO]2– tridentate phenolate ligands has been investigated with DFT calculations. The presence of both a cyclopentadienyl and a tridentate ligand complicates a usually simple reaction, the migratory insertion reaction being coupled with a fac → mer rearrangement of the tridentate ligand. Two routes have been explored for the overall migratory insertion process, depending on the order of the fac → mer and insertion steps. Calculations show that the dissociative (first fac → mer rearrangement, then migratory insertion) and the associative (first migratory insertion, then fac → mer rearrangement) pathways are in principle competitive. However, electronic effects of the phenyl substituents can favor one of the pathways. The study also points out the influence of the donor atom, due to the inversion at the donor atom required in order to achieve the fac → mer interconversion.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Section: ■ Results and Discussionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

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Rearrangement of Tridentate [OSO]-Type Ligands and Migratory Insertion Reaction Mechanisms in Cyclopentadienyl Tantalum Complexes

et al. 2012

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“…The symmetric amine triphenolate type ligands (type I) bearing three identical benzyl side arms have demonstrated rich coordination chemistry with a wide variety of main group and transition metals. [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] Their complexes show a range of catalytic properties in reactions such as aza-Diels-Alder, 7 lactide polymerisation 12 and sulfoxidation. 14 All these have taken advantage of the tetradentate nature of the ligands to stabilise well-defined monomeric complexes under catalytic conditions.…”

Section: Introductionmentioning

confidence: 99%

Synthesis, structures and catalytic properties of iron(iii) complexes with asymmetric N-capped tripodal NO3 ligands and a pentadentate N2O3 ligand

Tong¹,

Wong²,

Pascu³

et al. 2008

Dalton Trans.

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A new family of N-capped tripodal NO(3) proligands N,N-bis(2-hydroxy-3,5-di-tert-butylbenzyl)-N-(2'-hydroxy-5'-R-phenyl)amine [H(3)(L(n))] [when R= Me, n = 1; R= (t)Bu, n = 2; R = Cl, n = 3] with different substituents in one of the aryl rings and N,N-bis(2-hydroxy-3-tert-butylbenzyl)-N-(2'-hydroxy-5'-methylphenyl)amine [H(3)(L(4))] were synthesised. The preparation of a new pentadentate proligand N-methyl-N,N',N'-tris(2-hydroxy-3,5-di-tert-butylbenzyl)ethane-1,2-diamine [H(3)(L(5))] with an N(2)O(3) donor set is also reported. Reaction of the proligands [H(3)(L(n))] (n = 1-4) with iron(III) chloride in the presence of base (triethylamine) and 1-methylimidazole (1-Meim) as co-ligand led to the formation of iron complexes of the type [Fe(L(n))(1-Meim)] (n = 1-4) (1-4) respectively, while treatment of the trilithium salt of [H(3)(L(5))] with iron(III) chloride afforded [Fe(L(5))] (5). All complexes were structurally characterised by X-ray crystallography. In complexes 1-4, the ligands form five- and six-membered chelate rings with the iron centres which have distorted trigonal bipyramidal geometry with an N(2)O(3) coordination environment. Complex 5 adopts a similar distorted trigonal bipyramidal geometry also with N(2)O(3) coordination around the iron centre. The catalytic activity of these iron complexes towards epoxidation of styrene was examined.

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Pentakis(dimethylamido) Tantalum(V)

Fryzuk

Ballmann

Munhá

et al. 2011

Encyclopedia of Reagents for Organic Synthesis

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Ta(V) complexes of a bulky amine tris(phenolate) ligand: steric inhibition vs. chelate effect

Cited by 25 publications

References 13 publications

Rearrangement of Tridentate [OSO]-Type Ligands and Migratory Insertion Reaction Mechanisms in Cyclopentadienyl Tantalum Complexes

Rearrangement of Tridentate [OSO]-Type Ligands and Migratory Insertion Reaction Mechanisms in Cyclopentadienyl Tantalum Complexes

Synthesis, structures and catalytic properties of iron(iii) complexes with asymmetric N-capped tripodal NO3 ligands and a pentadentate N2O3 ligand

Pentakis(dimethylamido) Tantalum(V)

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