Palladium Carbon π-Bonded Complexes

Davies, Julian A.

doi:10.1016/b978-008046519-7.00081-2

Cited by 25 publications

(5 citation statements)

References 418 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The spectroscopic properties of complexes of the type (R 3 P)Pd(π-allyl)X have been intensively studied, and several dynamic processes have been described. In particular, for the 2-methylallyl derivatives (R 3 P)Pd(η 3 -C 3 H 4 Me)X partial or full equilibration of the allyl protons under various conditions has been reported . Nevertheless, the complexes 4a , b and 5a , b , containing the parent allyl, show some NMR spectral and structural peculiarities, which are now described in more detail.…”

Section: Resultsmentioning

confidence: 86%

A Dinuclear Palladium(I) Ethynyl Complex: Synthesis, Structure, and Dynamics

et al. 2001

View full text Add to dashboard Cite

The reaction of Pd(η3-C3H5)2 with PiPr3 at −30 °C affords yellow crystals of the PdII complex (iPr3P)Pd(η3-C3H5)(η1-C3H5) (1). At 20 °C 1 transforms into the dinuclear PdI complex {(iPr3P)Pd}2(μ-C3H5)2 (2) due to oxidative C−C coupling of two allyl groups with elimination of 1,5-hexadiene. Heating 1 or 2 in 1,6-heptadiene to 80 °C produces the Pd0 complex (iPr3P)Pd(η2,η2-C7H12) (3). {(η3-C3H5)PdCl}2 reacts with iPr3P to give (iPr3P)Pd(η3-C3H5)Cl (4b), from which further derivatives (iPr3P)Pd(η3-C3H5)X (X = OSO2CF3 (4a), C⋮CH (5a), CH3 (5b)) are obtained by replacement reactions. The mononuclear PdII-acetylide 5a and complex 3 combine to give the dinuclear PdI derivative {(iPr3P)Pd}2(μ-C3H5)(μ2-η2-C2H) (6). The Pd−Pd bond in 6 is unsymmetrically bridged by a π-allyl and a σ−π-ethynyl group, as determined by X-ray structure analysis. The structures of 1, 4a,b, and 6 are dynamic in solution, with 1 undergoing an exchange of the binding modes of the π- and σ-coordinated allyl groups and 4a,b displaying a π/σ-allyl group rearrangement, and in 6 the C⋮CH substituent oscillates in its π-coordination from one PdI atom to the other.

show abstract

Section: Resultsmentioning

confidence: 86%

A Dinuclear Palladium(I) Ethynyl Complex: Synthesis, Structure, and Dynamics

et al. 2001

View full text Add to dashboard Cite

show abstract

“…The potential of the ExIn approach to prepare substituted stilbenes that are of interest as scaffolds in medicinal chemistry and drug design (see, for example, resveratrol and combretastatin A-4, Scheme A) was investigated . Insertion reactions of allenes into Pd–C bonds are known, − as are the resultant η 3 -allyl complexes which have been used in organic synthesis, − so ExIn synthetic protocols could provide access to a range of alkenes, including stilbenes.…”

Section: Introductionmentioning

confidence: 99%

Palladium-Mediated CO₂ Extrusion Followed by Insertion of Allenes: Translating Mechanistic Studies to Develop a One-Pot Method for the Synthesis of Alkenes

et al. 2022

View full text Add to dashboard Cite

= H) is reported. This is an isoelectronic variant of CO 2 extrusion−insertion (ExIn) reactions previously developed using heterocumulenes for the synthesis of thioamides (from isothiocyanates, RNCS), amidines (from carbodiimides, RNCNR), and amides (from isocyanates, RNCO). Evidence that the key aryl-palladium intermediate reacts to form a stable allyl-palladium product via insertion of the allene at the C2 position that enables the synthesis of alkenes was provided by a combination of gas-phase multistage mass spectrometry (MS n ) experiments and condensed-phase monitoring using 1 H NMR spectroscopy as well as theoretical computational data. Isolation and X-ray crystallographic analysis of the salt [(phen)Pd(CH 2 CH(Ar)CHPh)] + (CF 3 CO 2 − ) (where Ar = 2,6dimethoxyphenyl) confirmed insertion of the allene at the C2 position and revealed a syn relationship between the two aryl groups. A survey of different hydrogen sources to promote the removal of palladium from the alkene product revealed that NaBH 4 provides the highest yield and with the Z-alkene as the major isomer.

show abstract

“…Palladium(0) complexes containing alkenes and/or alkynes as the only ligands are not as common and widespread in the literature as zerovalent palladium−phosphane complexes . The explanation for this needs to be sought independently in each case.…”

Section: Introductionmentioning

confidence: 99%

Chiral and Stable Palladium(0) Complexes of Polyunsaturated Aza-macrocyclic Ligands: Synthesis and Structural Analysis

Pla‐Quintana¹,

Torrent²,

Dachs³

et al. 2006

Organometallics

View full text Add to dashboard Cite

A novel type of chiral and stable palladium(0) complexes of polyunsaturated aza-macrocyclic ligands were prepared and fully characterized by means of NMR spectroscopy and X-ray diffraction. Fifteenmembered alkene-alkyne type ligands as well as 20-and 25-membered polyolefinic ligands showed a preference for tricoordination with the metal. The stereochemical complexity of these complexes is related to the different isomers that can be formed by complexation of the metal to either of the two faces of each of the olefins involved. The palladacyclopropane formulation of the palladium-olefin interaction offers a clear picture of the stereogenicity of the olefin carbon atoms when they are coordinated to the metal. The preorientation of the macrocyclic ligand and the prepositioning of the olefinic bonds for complex formation facilitated by six-membered chelate rings explain the stability of the structures. The conformation of the palladacyclohexanic rings is found to be crucial in the stereoisomers formed. These structural characteristics of the complexes have been studied in solution by NMR spectroscopy and in the solid state by X-ray diffraction analysis.

show abstract

Palladium Carbon π-Bonded Complexes

Cited by 25 publications

References 418 publications

A Dinuclear Palladium(I) Ethynyl Complex: Synthesis, Structure, and Dynamics

A Dinuclear Palladium(I) Ethynyl Complex: Synthesis, Structure, and Dynamics

Palladium-Mediated CO₂ Extrusion Followed by Insertion of Allenes: Translating Mechanistic Studies to Develop a One-Pot Method for the Synthesis of Alkenes

Chiral and Stable Palladium(0) Complexes of Polyunsaturated Aza-macrocyclic Ligands: Synthesis and Structural Analysis

Contact Info

Product

Resources

About

Palladium Carbon π-Bonded Complexes

Cited by 25 publications

References 418 publications

A Dinuclear Palladium(I) Ethynyl Complex: Synthesis, Structure, and Dynamics

A Dinuclear Palladium(I) Ethynyl Complex: Synthesis, Structure, and Dynamics

Palladium-Mediated CO2 Extrusion Followed by Insertion of Allenes: Translating Mechanistic Studies to Develop a One-Pot Method for the Synthesis of Alkenes

Chiral and Stable Palladium(0) Complexes of Polyunsaturated Aza-macrocyclic Ligands: Synthesis and Structural Analysis

Contact Info

Product

Resources

About

Palladium-Mediated CO₂ Extrusion Followed by Insertion of Allenes: Translating Mechanistic Studies to Develop a One-Pot Method for the Synthesis of Alkenes