Intermediates in the Conversion of π- to σ-Allylic Complexes of Palladium(II)<sup>1</sup>

Ramey, Kermit C.; Statton, Gary L.

doi:10.1021/ja00971a015

Cited by 32 publications

(5 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A section of the 1 H VT-NMR spectrum in the allylic region, Figure , shows a typical ABCDX-type spin system for the allylic protons ,− at 233 K. Given the greater trans influence of the NHC group when compared with the chloride ligand, the positions of allylic CH 2 protons pseudo -trans to the NHC ligand were unambiguously assigned with the aid of 1 H− 13 C HMBC and 1 H− 13 C HMQC experiments. A section of the 1 H− 13 C HMQC experiment is shown in Figure .…”

Section: Resultsmentioning

confidence: 99%

“…Such selective η 3 −η 1 exchange processes are very well recognized for the chiral phosphine bidentate ligand systems due to their enhanced steric and electronic effects. ,− The π to σ equilibrium is well documented for Pd(η 3 -C 3 H 5 )(L 1 )(L 2 ) complexes, where L 1 and L 2 = chloride, PPh 3 , P(OPh) 3 , DMSO, pyridine, and bidentate phosphine ligands. This is followed by temperature-dependent selective syn to anti interchange of the allylic protons, which usually takes place through the η 3 −η 1 −η 3 interconversion process under electronic or steric control ,− ,− (Scheme ).…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Synthesis, Structure, and Temperature-Dependent Dynamics of Neutral Palladium Allyl Complexes of Annulated Diaminocarbenes and Their Catalytic Application for C−C and C−N Bond Formation Reactions

et al. 2010

View full text Add to dashboard Cite

Imidazolinium salts 7,9-bis(2,4,6-trimethylphenyl)-6b,9a-dihydroacenaphtho [1,2-d]imidazolinium tetrafluoroborate and 7,9-bis(2,6-diisopropylphenyl)-6b,9a-dihydroacenaphtho[1,2-d]imidazolinium tetrafluoroborate, designated as [(BIAN-SIMes)(H)]BF 4 (3a) and [(BIAN-SIPr)(H)]BF 4 (3b), respectively, have been prepared and structurally characterized. The molecular structure of 3a shows the presence of a bifurcated hydrogen bond between the tetrafluoroborate anions and the central imidazolinium proton (-NCHN-). The palladium(II) complexes (η 3 -C 3 H 5 )Pd(BIAN-SIMes)Cl (5a) and (η 3 -C 3 H 5 )Pd(BIAN-SIPr)Cl ( 5b) have been synthesized. The temperature-dependent NMR behavior of σ-bonded palladium(II) complex 5b was studied. The crystal structure of 5b shows a localized single and double bond between the allyl ligand. The catalytic activities of the palladium(II) complexes 5a and 5b have been evaluated for Suzuki-type C-C coupling and for room-temperature C-N bond formation using aryl halides.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Synthesis, Structure, and Temperature-Dependent Dynamics of Neutral Palladium Allyl Complexes of Annulated Diaminocarbenes and Their Catalytic Application for C−C and C−N Bond Formation Reactions

et al. 2010

View full text Add to dashboard Cite

show abstract

“…The fact that the ethylene 1 H signals do not coalesce to a single resonance indicates that enantiomers 8 α , and 8 α‘ (and 8 β , and 8 β‘ ) do not interconvert on an NMR time scale. Such a process could have occurred by the normal π → σ allyl mechanism, − but the narrow 1 H line widths at −20 °C indicate such a process must have a free energy of activation greater than ca. 14 kcal/mol.…”

Section: Resultsmentioning

confidence: 99%

Mechanistic Studies of Catalytic Olefin Dimerization Reactions Using Electrophilic η³-Allyl−Palladium(II) Complexes

1996

View full text Add to dashboard Cite

The dimerization of olefins by well-defined cationic η3-allyl−palladium complexes of the type [(C3H5)Pd(L)(PR3)]+[BAr‘4]- (Ar‘ = [3,5-C6H3(CF3)2]; L = OEt2, H2O; R = cyclohexyl (Cy), n-butyl (nBu)) has been studied. These complexes react with ethylene or methyl acrylate at −80 °C with loss of L to form the η2-olefin complexes [(C3H5)Pd(η2-olefin)(PR3)]+[BAr‘4]- (olefin = H2CCH2, CH2CHC(O)OCH3). Upon warming, allyl−olefin coupling occurs. The dimerization of ethylene occurs rapidly at 0 °C with an observable ethyl−ethylene intermediate [(C2H5)Pd(C2H4)2(PCy3)]+[BAr‘4]-. Methyl acrylate reacts to form a stable acrylate chelate complex, [(CH3O(O)CCH2CH2)Pd(CH2CHC(O)OCH3)(PR3)]+[BAr‘4]-, which is the catalyst resting state for methyl acrylate dimerization which occurs at room temperature to give predominantly trans-dimethyl-2-hexenedioate.

show abstract

“…However, on altering the solvent to DMSO, incorporation of the solvent molecule into the coordination sphere of the palladium atom is more facile; thus, the solvent-assisted pathway becomes the dominant exchange process in solution. Interestingly, this exchange pathway is mechanistically similar to that observed in palladium complexes [(allyl)PdClL], generated by the addition of DMSO, phosphine, or arsine ligand, to allylpalladium chloride complexes [(allyl)Pd(μ-Cl)] 2 3 …”

Section: Resultsmentioning

confidence: 61%

Synthesis and Characterization of Allyl(β-ketoiminato)palladium(II) Complexes: New Precursors for Chemical Vapor Deposition of Palladium Thin Films

et al. 1999

View full text Add to dashboard Cite

Treatment of -ketoiminates with [(allyl)Pd(µ-Cl)] 2 affords volatile, air-stable allyl( -ketoiminato)palladium(II) complexes. The structure of [(methallyl)Pd(Phacac)] (Phacac ) MeCOCHCMeNPh) was determined by single-crystal X-ray diffraction. In solution 1 H NMR analyses indicate either a direct rotation of a planar allyl ligand about the allyl-palladium axis or a solvent-assisted exchange process involving the transient formation of a monodentate ketoiminato ligand. The physical properties of the complexes were modified by altering the -ketoiminato or the η 3 -allyl ligands. Some derivatives are liquid at room temperature and were known to be suitable for chemical vapor deposition of Pd thin films.The preparation of thin films of palladium by metal organic chemical vapor deposition (CVD) is becoming increasingly attractive for the fabrication of electronic devices 1 because such films have potentially useful applications in replacing gold as electrical contacts in integrated circuits and in making gas sensors, magnetooptical data storage devices, etc. 2 The largest obstacle to CVD of Pd films has been the lack of suitable precursors, as most volatile Pd complexes suffer from poor stability in air and moisture. 3 Recently, this problem was partially overcome by Puddephatt, who reported the preparation of volatile allyl( -diketonato)-palladium(II) complexes, which are liquid and stable at room temperature and are excellent CVD precursors for Pd films. 4 In view of these results, we felt it desirable to investigate analogous complexes having -ketoiminate ligands, which allow for organic functional group variation on the imine nitrogen as a possible way to finetune physical and chemical properties. In this article, we report the synthesis and characterization of such -ketoiminato complexes and a preliminary investigation of their application in the generation of Pd films. Experimental SectionGeneral Information and Materials. Infrared spectra were recorded on a Perkin-Elmer 2000 FT-IR spectrometer. 1 H and 13 C NMR spectra were recorded on a Bruker AM-400 or AMX-300 instrument. Mass spectra were obtained on a JEOL SX-102A instrument operating in fast atom bombardment (FAB) mode. Thermogravimetric analyses were made with a Seiko TG/DTA 300 instrument. Melting points were determined using Seiko SSC 5000 differential scanning calorimetry. Elemental analyses were performed at the NSC

show abstract

Intermediates in the Conversion of π- to σ-Allylic Complexes of Palladium(II)¹

Cited by 32 publications

References 0 publications

Synthesis, Structure, and Temperature-Dependent Dynamics of Neutral Palladium Allyl Complexes of Annulated Diaminocarbenes and Their Catalytic Application for C−C and C−N Bond Formation Reactions

Synthesis, Structure, and Temperature-Dependent Dynamics of Neutral Palladium Allyl Complexes of Annulated Diaminocarbenes and Their Catalytic Application for C−C and C−N Bond Formation Reactions

Mechanistic Studies of Catalytic Olefin Dimerization Reactions Using Electrophilic η³-Allyl−Palladium(II) Complexes

Synthesis and Characterization of Allyl(β-ketoiminato)palladium(II) Complexes: New Precursors for Chemical Vapor Deposition of Palladium Thin Films

Contact Info

Product

Resources

About

Intermediates in the Conversion of π- to σ-Allylic Complexes of Palladium(II)1

Cited by 32 publications

References 0 publications

Synthesis, Structure, and Temperature-Dependent Dynamics of Neutral Palladium Allyl Complexes of Annulated Diaminocarbenes and Their Catalytic Application for C−C and C−N Bond Formation Reactions

Synthesis, Structure, and Temperature-Dependent Dynamics of Neutral Palladium Allyl Complexes of Annulated Diaminocarbenes and Their Catalytic Application for C−C and C−N Bond Formation Reactions

Mechanistic Studies of Catalytic Olefin Dimerization Reactions Using Electrophilic η3-Allyl−Palladium(II) Complexes

Synthesis and Characterization of Allyl(β-ketoiminato)palladium(II) Complexes: New Precursors for Chemical Vapor Deposition of Palladium Thin Films

Contact Info

Product

Resources

About

Intermediates in the Conversion of π- to σ-Allylic Complexes of Palladium(II)¹

Mechanistic Studies of Catalytic Olefin Dimerization Reactions Using Electrophilic η³-Allyl−Palladium(II) Complexes