Phosphinito- and phosphonito-oxazoline Pd(ii) complexes as CO/ethylene insertion intermediates: synthesis and structural characterization

Agostinho, Magno; Braunstein, Pierre; Welter, Richard

doi:10.1039/b616962g

Cited by 26 publications

(23 citation statements)

References 76 publications

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“…Palladium compounds are widely utilized for these reactions with ethylene, norbornenes, the other alkenyl compounds, alkenyl halides, aryl alkenyl and alkenyl esters 164–179. The other metal compounds are iron,180–182 manganese183, 184 and rhodium metal compounds 185…”

Section: Synthesis Of Carbonyl Group‐containing Organometallic Intrammentioning

confidence: 99%

Carbonyl group‐containing organometallic intramolecular‐coordination five‐membered ring compounds

Omae¹

2010

Applied Organom Chemis

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Carbonyl group-containing organometallic intramolecular-coordination five-membered ring compounds are easily synthesized by the following five reaction methods: (1) cyclometalation, especially, orthometalation reactions; (2) the reactions of the moieties of an unsaturated carbon-carbon bond attached to a carbonyl group (C C-CO, C C-CO); (3) the reactions of an unsaturated carbon-carbon bond with carbon monoxide (C C and CO, C C and CO); (4) carbonylative ring expansion reactions; and (5) others. These compounds are very easily and regio-specifically synthesized with many kinds of metal compounds, including both transition metals and main group metals. Many of such the reactions are easily applied to organic syntheses.

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Section: Synthesis Of Carbonyl Group‐containing Organometallic Intrammentioning

confidence: 99%

Carbonyl group‐containing organometallic intramolecular‐coordination five‐membered ring compounds

Omae¹

2010

Applied Organom Chemis

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“…23 Another strategy to overcome problems associated to co-catalysts is to replace halide catalyst/aluminium cocatalyst systems by well-defined σ-alkyl complexes that do not require activation by organoaluminium compounds.38,39 A number of palladium methyl derivatives of the type [Pd(Me)(L′)(P-N)]+ have been reported (where L′ is a weakly coordinating ligand, usually MeCN) which oligomerize ethylene21, 23,25,32,33,[40][41][42] or copolymerize olefins and CO without cocatalysts.42-45 Although these systems are only moderately active, they provide a wealth of information on the mechanism of polymerization and copolymerization reactions, because they enabled the isolation of stable products arising from the migratory insertion of olefins and/or CO into the Pd-CH3 bond. 23,[41][42][43][44][45][46][47][48] These compounds can undergo unusual but potentially very interesting processes, such as the insertion of polar monomers.43,46,47 Therefore, it is rather surprising that analogous σ-alkyl or aryl complexes of nickel stabilized with [P,N] ligands have received very little attention as single-component catalysts. A few neutral σ-organonickel derivatives with anionic [P,N] ligands have been tested for this purpose, but in general they showed low catalytic activity.…”

Section: Introductionmentioning

confidence: 99%

Migratory insertion reactions of nickel and palladium σ-alkyl complexes with a phosphinito-imine ligand

et al. 2012

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Ligand exchange reactions have been used for the synthesis of metallacyclic complexes of Ni and Pd of the type [M[upper bond 1 start](CH(2)CMe(2)-o-C(6)[upper bond 1 end]H(4))(P-N)], where P-N is the phosphinito-imine ligand P(iPr)(2)OC(Me)[double bond, length as m-dash]N(2,6-C(6)H(3)(iPr)(2). The protic acid [H(OEt(2))(BAr'(4))] (Ar' = 3,5-C(6)H(3)(CF(3))(2)) selectively cleaves one of the two σ metal-carbon bonds, affording cationic monoalkyl complexes. Nickel monoalkyls stabilized with Et(2)O or MeCN ligands are thermally unstable and spontaneously undergo a decomposition process that ultimately leads to the breakdown of the phosphinito-imine ligand. In contrast, cationic alkylpalladium derivatives are thermally very stable, allowing the isolation of a formally unsaturated monoalkyl complex stabilized by an intramolecular π-arene interaction. Although monoalkynickel and -palladium phosphinito-imine derivatives are inactive as ethylene polymerization or copolymerization catalysts, they readily experience migratory insertion reactions. A palladium chelate arising from the successive insertion of CO and ethylene has been isolated and characterized.

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“…Notably, the norbornylpalladium complexes, synthesized via single N-insertion into a catalytically active species, in a process of polyolefin formation, are rare [ 81 ]. Only a few examples had been achieved either by introducing a functionalized alkyl on the olefin [ 82 , 83 , 84 , 85 , 86 , 87 , 88 ], or through a neutral palladium species that showed relatively lower affinity to the olefins [ 89 , 90 , 91 ]. The NMR data measured in CDCl 3 show that two diastereomers, exclusively in trans -diastereomers ( T -form), are identified for 2a – b , according to the NOE cross-peaks between the norbornyl and ortho -H of pyridine in the NOESY spectra.…”

Section: Resultsmentioning

confidence: 99%

Kinetics, Mechanism and Theoretical Studies of Norbornene-Ethylene Alternating Copolymerization Catalyzed by Organopalladium(II) Complexes Bearing Hemilabile α-Amino–pyridine

Huang

Liu

et al. 2017

Molecules

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Cationic methylpalladium complexes bearing hemilabile bidentate α-amino–pyridines can serve as effective precursors for catalytic alternating copolymerization of norbornene (N) and ethylene (E), under mild conditions. The norbornyl palladium complexes in the formula of {[RHNCH2(o-C6H4N)]Pd(C7H10Me)(NCMe)}(BF4) (R = iPr (2a), tBu (2b), Ph (2c), 2,6-Me2C6H3 (2d), 2,6-iPr2C6H3 (2e)) were synthesized via single insertion of norbornene into the corresponding methylpalladium complexes 1a–1e, respectively. Both square planar methyl and norbornyl palladium complexes exhibit facile equilibria of geometrical isomerization, via sterically-controlled amino decoordination–recoordination of amino–pyridine. Kinetic studies of E-insertion, N-insertion of complexes 1 and 2, and the geometric isomerization reactions have been examined by means of VT-NMR, and found in excellent agreement with the results estimated by DFT calculations. The more facile N-insertion in the cis-isomers, and ready geometric isomerization, cooperatively lead to a new mechanism that accounts for the novel catalytic formation of alternating COC.

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Phosphinito- and phosphonito-oxazoline Pd(ii) complexes as CO/ethylene insertion intermediates: synthesis and structural characterization

Cited by 26 publications

References 76 publications

Carbonyl group‐containing organometallic intramolecular‐coordination five‐membered ring compounds

Carbonyl group‐containing organometallic intramolecular‐coordination five‐membered ring compounds

Migratory insertion reactions of nickel and palladium σ-alkyl complexes with a phosphinito-imine ligand

Kinetics, Mechanism and Theoretical Studies of Norbornene-Ethylene Alternating Copolymerization Catalyzed by Organopalladium(II) Complexes Bearing Hemilabile α-Amino–pyridine

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