A systematic study on the synthesis, reactivity and structure of ortho-palladated aryloximes, including the first cyclopalladated aryloximato and iminoaryloxime complexes

Vicente, José; Chicote, Mariá‐Teresa; Abellán-López, Antonio; Bautista, Delia

doi:10.1039/c1dt11445j

Cited by 21 publications

(28 citation statements)

References 41 publications

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“…The CNOH and the metalate C4 carbon atoms are shifted to high frequencies in comparison with the free oxime ligand, which is in agreement with the chelating coordination mode of the oxime ligand via the iminic N and the C4 carbon atoms. Similar values have been reported for related Pd(II) complexes with oxime ligands …”

Section: Resultssupporting

confidence: 89%

“…This coordination geometry is supported by the structural parameter τ4 values (0.15) . The ten atoms of the oxime ligand are coplanar (root‐mean‐square deviation of 0.007 Å, maximum deviation N1: 0.016(3) Å), with the Pd atom and both S atoms lying below the ligand plane, by 0.135(3), 0.232(6) and 0.802(5) Å, respectively; the planarity of the ligand is similar to that found in similar Pd complexes [14, 28b, 30]. Both PS distances (2.0043(13) and 1.9883(13) Å) are longer than is found in the free dppmS 2 ligand (1.941(1) Å) .…”

Section: Resultsmentioning

confidence: 69%

“…The IR spectra of 1 – 3 were compared with that of the free ligand in order to get a clue about the coordination and mode of coordination of ligand to Pd in the first stage. A characteristic band assigned to CN group was observed at higher frequency than the free ligand at 1602 cm −1 ( 1 ), 1604 cm −1 ( 2 ) and 1610 cm −1 ( 3 ) indicating flow of electrons from ligand to metal . The presence of ClO 4 − group was evidenced by two bands in the regions 1100 and 622 cm −1 .…”

Section: Resultsmentioning

confidence: 95%

“…These oxime palladacycles possess remarkable air, moisture and thermal stability with excellent TONs in organic and aqueous solvent systems . Although the syntheses of various oxime palladacycles have been reported, their reactivity has been very scarcely studied …”

Section: Introductionmentioning

confidence: 99%

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Mono‐ and dinuclear oxime palladacycles bearing diphosphine ligands: An unusual coordination mode for dppe

Samiee

Shiralinia

Hoveizi

et al. 2019

Applied Organom Chemis

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Three new oxime‐based palladacycles, namely [Pd{C,N‐C6H4{C(Me)NOH}‐2}(dppm)]ClO4 (1), [Pd2{C,N‐C6H4{C(Me)NOH}‐2}2(dppe)2(μ‐dppe)](ClO4)2 (2) and [Pd{C,N‐C6H4{C(Me)NOH}‐2}(dppmS2)]ClO4 (3), were synthesized by the reaction of dinuclear oxime complex [Pd{C,N‐C6H4{C(Me)NOH}‐2}(μ‐Cl)]2 with different diphosphine ligands (dppm, dppe and dppmS2). The synthesized complexes were characterized using Fourier transform infrared, 31P NMR, 1H NMR and 13C NMR spectroscopic methods and elemental analyses, and their molecular structures were elucidated using X‐ray crystallography. The structure of 2 is worthy of note as it is the first oxime palladacycle where there are both bridging (P–) and chelating (P^P) dppe ligands, giving rise to a dinuclear complex. The palladium atom is in a five‐coordinate, square pyramidal P3NC environment, while in 3 the palladium atom is in a distorted square planar environment, coordinated by the oxime ligand and a chelating (S^S) dppmS2 ligand. These complexes were employed as efficient catalysts for the Suzuki–Miyaura cross‐coupling reaction of several aryl bromides with phenylboronic acid. The in vitro cytotoxicity of the compounds was also evaluated against human tumour cell lines (HT29, A549 and HeLa) using the MTT assay method. The results indicate that the dinuclear complex 2 has greater catalytic and anticancer activity in comparison with the mononuclear complexes 1 and 3.

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Section: Resultssupporting

confidence: 89%

Section: Resultsmentioning

confidence: 69%

Section: Resultsmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Mono‐ and dinuclear oxime palladacycles bearing diphosphine ligands: An unusual coordination mode for dppe

Samiee

Shiralinia

Hoveizi

et al. 2019

Applied Organom Chemis

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“…Cyclopalladated complexes (41-60) can be generated from other nitrogendonor ligands such as benzylideneamines, ferrocenylmethylamines, pyridine, quinoline, benzoquinoline, and amide, with different palladation sources. [28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45]…”

Section: Other Nitrogen-donor Complexesmentioning

confidence: 99%

Design and synthesis of chiral organopalladium-amine complexes

Yap¹

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Bn benzyl Bu butyl br broad c concentration for optical rotation analysis calcd calculated conc. concentrated CDCl3 chloroform-d1 CD2Cl2 dichloromethane-d2 CHCl3 chloroform CH3CN acetonitrile Claisen's alkali a strong base prepared by 8.81 g KOH dissolved in 6 ml of XI Summary This thesis describes the design and synthesis of chiral organopalladium-amine complexes and their applications in stoichiometric asymmetric synthesis. A brief introduction on the organopalladium-amine complexes, the research development and the objective of this project were presented in Chapter 1. In Chapter 2, a functionalized amine, 1-(2,5-di-tert-butylphenyl)-N,Ndimethylethanamine was designed and synthesized, but the ortho-palladation reaction did not give the desired palladacycle. An unexpected C−N bond cleavage was observed and gave two C−N bond cleavage complexes. The mechanistic studies on the formation of C−N bond cleavage complex was carried out, but no substantial conclusion can be made yet. The initial step is likely β-hydride elimination and it is a base promoted reaction. Chapter 3 describes the synthesis of slightly less bulky amine ligand, 1-(2,5-diiso-propylphenyl)-N,N-dimethylethanamine from p-di-iso-propylbenzene. By optimizing the reaction conditions including replacement of some of the reagents, it resulted in increased of the overall yield of the amine ligand. The ortho-palladation reaction gave the desired palladacycle and C−N bond cleavage complex by varying the palladating agent used. The racemic dimeric complex was resolved by separation of the (S)-prolinate diastereomeric derivatives via column chromatography. The efficiency of the palladacycle was assessed via the asymmetric intramolecular endocycloaddition reaction and a better stereoselectivity was obtained. In chapter 4 describes the synthesis of an electron-withdrawing group functionalized benzyl palladacycle to investigate the electronic effect of the palladacycle in asymmetric Diel-Alder reaction. The amine ligand, 1-(2,5dichlorophenyl)-N,N-dimethylethanamine was synthesized via three step synthetic XII route with high overall yield and ortho-palladation with Pd(OAc)2 to give the acetatebridged dimeric palladacycle. The racemic dimer was resolved with optically active sodium prolinate and by treatment of the corresponding diastereomer with aqueous 1M HCl produced the chiral chloro-bridged dimer. The efficiency of the palladacycle was examined via Diels-Alder reaction between DMPP-coordinated complex and ethyl vinyl ketone, however poor stereoselectivity was observed. The chiral dimeric complex was converted to the cationic complex and used in asymmetric hydrophosphination reaction between diphenylphosphine and DMAD to give one diastereomeric product.

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Multiple Roles of Isocyanides in Palladium‐Catalyzed Imidoylative Couplings: A Mechanistic Study

Perego

Fleurat‐Lessard

Kaı̈m

et al. 2016

Chemistry A European J

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Kinetic, spectroscopic and computational studies examining a palladium-catalyzed imidoylative coupling highlight the dual role of isocyanides as both substrates and ligands for this class of transformations. The synthesis of secondary amides from aryl halides and water is presented as a case study. The kinetics of the oxidative addition of ArI with RNC-ligated Pd species have been studied and the resulting imidoyl complex [(ArC=NR)Pd(CNR) I] (Ar=4-F-C H , R=tBu) has been isolated and characterized by X-ray diffraction. The unprecedented ability of this RNC-ligated imidoyl-Pd complex to undergo reductive elimination at room temperature to give the amide in the presence of water and an F /HF buffer is demonstrated. Its behavior in solution has also been characterized, revealing an unexpected strong tendency to give cationic complexes, and notably [(ArC=NR)Pd(CNR) ] with excess isocyanide and [(ArC=NR)Pd(PP^ )(CNR)] with bidentate phosphines (PP^ ). These species may be responsible for catalyst deactivation and side-reactions. Ab initio calculations performed at the DFT level allowed us to rationalize the multiple roles of RNC in the different steps of the catalytic cycle.

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A systematic study on the synthesis, reactivity and structure of ortho-palladated aryloximes, including the first cyclopalladated aryloximato and iminoaryloxime complexes

Cited by 21 publications

References 41 publications

Mono‐ and dinuclear oxime palladacycles bearing diphosphine ligands: An unusual coordination mode for dppe

Mono‐ and dinuclear oxime palladacycles bearing diphosphine ligands: An unusual coordination mode for dppe

Design and synthesis of chiral organopalladium-amine complexes

Multiple Roles of Isocyanides in Palladium‐Catalyzed Imidoylative Couplings: A Mechanistic Study

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