Preparation and reactions of palladium(0)–olefin complexes with iminophosphine ligands

Antonaroli, Simonetta; Crociani, B.

doi:10.1016/s0022-328x(98)00472-0

Cited by 55 publications

(48 citation statements)

References 26 publications

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“…Protocol (d): Analogously, different palladium(0) olefin complexes can be obtained by the exchange of the ligands [32][33][34]. Again the coordinating capability of the exchanged ligands is a strict prerequisite.…”

Section: Synthesis Of the Palladium(0) Olefin Complexesmentioning

confidence: 99%

“…On the contrary, when N-N, N-S and N-P molecules are employed as ancillary ligands their 1 H NMR signals are all shifted downfield, indicating the predominant r-nature of the ensuing bonds. The formation of different isomers as a function of the olefin structure and of the symmetry of the ancillary ligand can be observed (Scheme 3) [4,30,32,34,[40][41][42][43]. Usually these species undergo extensive fluxionality and the RT 1 H NMR spectra of the complexes are characterized by rapid interconversion among isomers and only averaged spectra are detectable.…”

Section: Characterization Of the Complexesmentioning

confidence: 99%

“…Taking advantage from the peculiar steric characteristics of the tetramethyl-ethene-tetracarboxylate (tmetc) the olefin exchange equilibria were also studied from the kinetic point of view [26,31,32,34,39,43,[63][64][65]. It has been shown that the rates of exchange are strongly dependent on the steric requirement of the ancillary ligand and the mechanism is associative in nature.…”

Section: Olefin Exchangementioning

confidence: 99%

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Synthesis, stability and reactivity of palladium(0) olefin complexes bearing labile or hemi-labile ancillary ligands and electron-poor olefins

Canovese

Visentin

2010

Inorganica Chimica Acta

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a b s t r a c tAn overview of the general features of electron-poor olefin stabilized palladium(0) complexes bearing labile and hemi-labile ancillary ligands is presented. In particular, we have summarized the synthetic methodologies, the ligands commonly used, and the characterization of such complexes. The behavior of these species in solution is also described with particular attention to their fluxional rearrangements and reactivity. Thus, olefin exchange reactions are described and a comprehensive order of coordinative capability of the most widely used electron-poor alkenes is presented. The reactions of the title complexes dealing with olefin isomerization, oxidative addition, and formation of palladacyclopentadiene derivatives are eventually reported together with their main structural characteristics.

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Section: Synthesis Of the Palladium(0) Olefin Complexesmentioning

confidence: 99%

Section: Characterization Of the Complexesmentioning

confidence: 99%

Section: Olefin Exchangementioning

confidence: 99%

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Synthesis, stability and reactivity of palladium(0) olefin complexes bearing labile or hemi-labile ancillary ligands and electron-poor olefins

Canovese

Visentin

2010

Inorganica Chimica Acta

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“…[27] o-(Diphenylphosphino)benzaldehyde [28] (1.66 g, 5.73 mmol) was treated with 2,6-dimethylaniline (1.0 mL, 8.60 mmol) in MeOH/CH 2 Cl 2 (3/1, 60 mL) under N 2 at room temperature. After stirring for 48 h, the solution was concentrated to about 10 mL and cooled to À20 8C to give o-(PPh 2 )C 6 H 4 C=NC 6 H 3 Me 2 -2,6 as a light yellow microcrystalline solid over 24 h. The solids were collected by filtration and washed with cold methanol.…”

Section: 75 (S 3 H; P-nc 6 H 2 a C H T U N G T R E N N U N G (Chmentioning

confidence: 99%

Synthesis and Reactivity of Rare Earth Metal Alkyl Complexes Stabilized by Anilido Phosphinimine and Amino Phosphine Ligands

Liu

Cui

et al. 2007

Chemistry A European J

106

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Anilido phosphinimino ancillary ligand H(2)L(1) reacted with one equivalent of rare earth metal trialkyl [Ln{CH(2)Si(CH(3))(3)}(3)(thf)(2)] (Ln=Y, Lu) to afford rare earth metal monoalkyl complexes [L(1)LnCH(2)Si(CH(3))(3)(THF)] (1 a: Ln=Y; 1 b: Ln=Lu). In this process, deprotonation of H(2)L(1) by one metal alkyl species was followed by intramolecular C--H activation of the phenyl group of the phosphine moiety to generate dianionic species L(1) with release of two equivalnts of tetramethylsilane. Ligand L(1) coordinates to Ln(3+) ions in a rare C,N,N tridentate mode. Complex l a reacted readily with two equivalents of 2,6-diisopropylaniline to give the corresponding bis-amido complex [(HL(1))LnY(NHC(6)H(3)iPr(2)-2,6)(2)] (2) selectively, that is, the C--H activation of the phenyl group is reversible. When 1 a was exposed to moisture, the hydrolyzed dimeric complex [{(HL(1))Y(OH)}(2)](OH)(2) (3) was isolated. Treatment of [Ln{CH(2)Si(CH(3))(3)}(3)(thf)(2)] with amino phosphine ligands HL(2-R) gave stable rare earth metal bis-alkyl complexes [(L(2-R))Ln{CH(2)Si(CH(3))(3)}(2)(thf)] (4 a: Ln=Y, R=Me; 4 b: Ln=Lu, R=Me; 4 c: Ln=Y, R=iPr; 4 d: Ln=Y, R=iPr) in high yields. No proton abstraction from the ligand was observed. Amination of 4 a and 4 c with 2,6-diisopropylaniline afforded the bis-amido counterparts [(L(2-R))Y(NHC(6)H(3)iPr(2)-2,6)(2)(thf)] (5 a: R=Me; 5 b: R=iPr). Complexes 1 a,b and 4 a-d initiated the ring-opening polymerization of d,l-lactide with high activity to give atactic polylactides.

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“…The zero-valent complexes [Pd(η 2 -dmfu)(PϪN)] {dmfu ϭ dimethyl fumarate; PϪN ϭ 2-(PPh 2 )C 6 H 4 Ϫ1-CHϭNR, R ϭ alkyl and aryl group}, [11] are quite active catalysts (or catalyst precursors) in the coupling of organostannanes with aryl halides. [12] The catalytic efficiency is retained for a prolonged period of time and increases considerably on going from alkyl to aryl N-substituents, and also in the presence of the free iminophosphane for a PϪN/ Scheme 2.…”

Section: Introductionmentioning

confidence: 99%

Kinetic Studies of the Oxidative Addition and Transmetallation Steps Involved in the Cross‐Coupling of Alkynyl Stannanes with Aryl Iodides Catalysed by η²‐(Dimethyl fumarate)(iminophosphane)palladium(0) Complexes

et al. 2004

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The complexes [Pd(η2‐dmfu)(P−N)] {dmfu = dimethyl fumarate; P−N = 2‐(PPh2)C6H4−1‐CH=NR, R = C6H4OMe‐4 (1a), CHMe2 (2a), C6H3Me2‐2,6 (3a), C6H3(CHMe2)2‐2,6 (4a)} undergo dynamic processes in solution which consist of a P−N ligand site exchange through initial rupture of the Pd−N bond at lower energy and an olefin dissociation‐association at higher energy. According to equilibrium constant values for olefin replacement, the complex [Pd(η2‐fn)(P−N)] (fn = fumaronitrile, 1b) has a greater thermodynamic stability than its dmfu analogue 1a. The kinetics of the oxidative addition of ArI (Ar = C6H4CF3‐4) to 1a and 2a lead to the products [PdI(Ar)(P−N)] (1c, 2c) and obey the rate law, kobs = k1A + k2A[ArI]. The k1A step involves oxidative addition to a reactive species [Pd(solvent)(P−N)] formed from dmfu dissociation. The k2A step is better interpreted in terms of oxidative addition to a species [Pd(η2‐dmfu)(solvent)(κ1‐P−N)] formed in a pre‐equilibrium step from Pd−N bond breaking. The complexes 1c and 2c react with PhC≡CSnBu3 in the presence of an activated olefin (ol = dmfu, fn) to yield the palladium(0) derivatives [Pd(η2‐ol)(P−N)] along with ISnBu3 and PhC≡CAr. The kinetics of the transmetallation step, which is rate‐determining for the overall reaction, obey the rate law: kobs = k2T[PhC≡CSnBu3]. The k2T values are markedly enhanced in more polar solvents such as CH3CN and DMF. The solvent effect and the activation parameters suggest an associative SE2 mechanism with substantial charge separation in the transition state. The kinetic data of the above reactions in various solvents indicate that, for the cross‐coupling of PhC≡CSnBu3 with ArI catalysed by 1a or 2a, the rate‐determining step is represented by the oxidative addition and that CH3CN is the solvent in which the highest rates are observed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

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Preparation and reactions of palladium(0)–olefin complexes with iminophosphine ligands

Cited by 55 publications

References 26 publications

Synthesis, stability and reactivity of palladium(0) olefin complexes bearing labile or hemi-labile ancillary ligands and electron-poor olefins

Synthesis, stability and reactivity of palladium(0) olefin complexes bearing labile or hemi-labile ancillary ligands and electron-poor olefins

Synthesis and Reactivity of Rare Earth Metal Alkyl Complexes Stabilized by Anilido Phosphinimine and Amino Phosphine Ligands

Kinetic Studies of the Oxidative Addition and Transmetallation Steps Involved in the Cross‐Coupling of Alkynyl Stannanes with Aryl Iodides Catalysed by η²‐(Dimethyl fumarate)(iminophosphane)palladium(0) Complexes

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Preparation and reactions of palladium(0)–olefin complexes with iminophosphine ligands

Cited by 55 publications

References 26 publications

Synthesis, stability and reactivity of palladium(0) olefin complexes bearing labile or hemi-labile ancillary ligands and electron-poor olefins

Synthesis, stability and reactivity of palladium(0) olefin complexes bearing labile or hemi-labile ancillary ligands and electron-poor olefins

Synthesis and Reactivity of Rare Earth Metal Alkyl Complexes Stabilized by Anilido Phosphinimine and Amino Phosphine Ligands

Kinetic Studies of the Oxidative Addition and Transmetallation Steps Involved in the Cross‐Coupling of Alkynyl Stannanes with Aryl Iodides Catalysed by η2‐(Dimethyl fumarate)(iminophosphane)palladium(0) Complexes

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Kinetic Studies of the Oxidative Addition and Transmetallation Steps Involved in the Cross‐Coupling of Alkynyl Stannanes with Aryl Iodides Catalysed by η²‐(Dimethyl fumarate)(iminophosphane)palladium(0) Complexes