Synthesis and X-ray structure of new cationic allyl complexes of palladium(II) with α-diimine ligands

Mechria, Ali; Rzaigui, M.; Bouachir, Faouzi

doi:10.1016/s0040-4039(00)01096-0

Cited by 18 publications

(3 citation statements)

References 19 publications

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“…As a consequence of this arrangement, the four anthryl hydrogen atoms in 1- and 8- positions are facing each other, thus preventing the counterion from locating near the metal center. In fact, the closest counterion, as already found in the crystal lattice of similar catalysts, , is located in the back, above the diimine carbons of the nitrogen ligand (Figure ), and weakly interacts with the aromatic hydrogen atoms of the ligand. Interestingly the interionic structure of 2g closely resembles that found in a similar dimethyl ortho-substituted aryl α-diimine complex .…”

Section: Results and Discussionmentioning

confidence: 53%

New Aryl α-Diimine Palladium(II) Catalysts in Stereocontrolled CO/Vinyl Arene Copolymerization

et al. 2013

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The effect of the catalyst structure on the stereoselectivity of CO/vinyl arene copolymerization has been studied with the aim of developing catalytic systems able to improve the yields while maintaining the high degree of copolymer isotacticity previously obtained using achiral nitrogen ligands. Aryl α-diimine ligands having extended aromatic rings (Ar)2DABMe2, with Ar = 1-C10H7 (e), 1-C14H9 (f), 9-C14H9 (g), have been synthesized, and α-diimine coordination to cationic methylpalladium complexes has been investigated in solution, by means of NMR spectroscopy, and in the solid state for [Pd(Me)(NCMe)((9-C14H9) 2DABMe2)][PF6] (2g). The performance of these catalysts in CO/vinyl arene copolymerization, under mild conditions, was analyzed in terms of productivity and degree of stereoregularity of the resulting polyketones. In comparison with previous results, a remarkable enhancement in the yield of isotactic copolymer was observed using the new achiral 9-anthryl α-diimine ligand g, confirming that the ortho disubstitution and the extended aromatic rings play key roles in obtaining good stereoselectivity and good productivity. To perform a structural analysis of the first steps of the CO/p-methylstyrene copolymerization, complex [Pd(Me)(CO)((9-C14H9)2DABMe2)] [BAr′4] (3g) was used as a starting point: NMR investigation reveals the stereoselective formation of the olefin/CO/olefin insertion product (6g), which prevalently exists in solution in only one diastereoisomeric form, thus justifying the observed high polymer isotacticity

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Section: Results and Discussionmentioning

confidence: 53%

New Aryl α-Diimine Palladium(II) Catalysts in Stereocontrolled CO/Vinyl Arene Copolymerization

et al. 2013

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“…[Pd(Tol-BIAN)( η 3 -CH 2 C(CH 3 )CH 2 )][PF 6 ] (7b). This compound was prepared by the method reported for 7l . The required 8 was prepared as described above.…”

Section: Methodsmentioning

confidence: 99%

Method of Establishing the Lewis Acidity of a Metal Fragment Based on the Relative Binding Strengths of Ar-BIAN Ligands (Ar-BIAN = Bis(aryl)acenaphthenequinonediimine)

Gasperini¹,

Ragaini²

2004

Organometallics

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The relative coordination strengths of a series of differently substituted Ar-BIAN ligands (Ar-BIAN ) bis(aryl)acenaphthenequinonediimine) to a series of palladium complexes in both the formal 0 and 2 oxidation states have been determined. In all cases a good to excellent linearity of log K eq with respect to the Hammett σ constants of the substituents on the aryl fragments of the ligands was observed. The resulting F constant is proposed to be a good indication of the Lewis acidity of the metal fragment, a physical quantity for which experimental parameters have been determined only for a limited class of compounds. The obtained parameters allow a comparison not only of different olefin complexes among themselves but also with respect to different metal fragments such as Pd(OAc) 2 , Pd(Me)Cl, and a π-allyl complex. The Lewis acidity of the olefin complexes is extremely variable and ranges from the less acidic (Pd(Ar-BIAN)(DMFU); DMFU ) dimethyl fumarate) to two of the most acidic (Pd(Ar-BIAN)(TCNE) and Pd(Ar-BIAN)(FN); TCNE ) tetracyanoethylene, FN ) fumarodinitrile) complexes among those examined. A cationic π-allyl complex has the highest Lewis acidity among the complexes examined. The importance of steric effects is examined in some cases.

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“…The coordination chemistry of 1,4-diazabutadiene (dab) ligands, bis (arylimino)acenaphtene (Ar-BIAN) ligands, bis (phenylimino)camphene (Ph-BIC) and their complexes [1][2][3][4][5][6][7][8] has attracted much interest due to their unusual electron donor and acceptor properties [9,10]. Their complexes have been reported essentially for late transition metals.…”

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confidence: 99%

Synthesis, characterization and crystal structure of diamagnetic tetracoordinated chromium (II) complexes supported by α-diimine ligands

Turki

Guerfel

Bouachir

2006

Inorganic Chemistry Communications

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Synthesis and X-ray structure of new cationic allyl complexes of palladium(II) with α-diimine ligands

Cited by 18 publications

References 19 publications

New Aryl α-Diimine Palladium(II) Catalysts in Stereocontrolled CO/Vinyl Arene Copolymerization

New Aryl α-Diimine Palladium(II) Catalysts in Stereocontrolled CO/Vinyl Arene Copolymerization

Method of Establishing the Lewis Acidity of a Metal Fragment Based on the Relative Binding Strengths of Ar-BIAN Ligands (Ar-BIAN = Bis(aryl)acenaphthenequinonediimine)

Synthesis, characterization and crystal structure of diamagnetic tetracoordinated chromium (II) complexes supported by α-diimine ligands

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