From mononuclear to multinuclear complexes of palladium containing unsaturated hydrocarbon ligands

Kurosawa, Hideo

doi:10.1016/j.jorganchem.2004.08.005

Cited by 27 publications

(14 citation statements)

References 74 publications

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“…and ½Pd 2 ðl-PBu t 2 ÞðPHCy 2 Þ 4 BF 4 [19c], but still in agreement with the trend observed for [{Pd 2 (CH 2 C 6 H 4 P(o-tolyl) 2 -jC, P) 2 (l 3 -3,5-dmpz-N,N 0 ,C 4 ) 2 Ag(g 2 -l-ClO 4 )} 2 ] [19d], [Pd 3 (l 3 -Cl) 2 (HqnS) 6 ]Cl 2 [20] and [Pd 3 (l-S) 2 -((CO 2 Me) 2 bpy) 3 ][ClO 4 ] 2 [21].…”

Section: Introductionsupporting

confidence: 79%

“…Pd(I)-Pd(I) complexes have received considerable attention over the past few years as a result of their ability to react with a wide range of substrates, with important potential applications in organometallic catalysis [1][2][3][4][5][6]. However, a common structural feature of the majority of these complexes is that the center of palladium(I) generally adopts square-planar (or distorted square-planar) and trigonal coordination geometries.…”

Section: Introductionmentioning

confidence: 99%

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Synthesis, structure and photoluminescence of a novel palladium(I) compound: [Pd3(μ3-Cl)2(dppp)3][Pd2(μ2-Cl)3(PPh3)2](PPh3)2

Luo

Huang

Lin

et al. 2008

Inorganic Chemistry Communications

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Section: Introductionsupporting

confidence: 79%

Section: Introductionmentioning

confidence: 99%

Synthesis, structure and photoluminescence of a novel palladium(I) compound: [Pd3(μ3-Cl)2(dppp)3][Pd2(μ2-Cl)3(PPh3)2](PPh3)2

Luo

Huang

Lin

et al. 2008

Inorganic Chemistry Communications

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“…The μ-η 2 :η 2 -binding mode of two π-systems in sandwich dipalladium(I) complexes has been previously examined by others. 6,19,87 Diene binding is described through two key interactions: donation of the diene HOMO to the Pd–Pd [dσ–dσ]* antibonding orbital (Figure 6a) and back-donation of the Pd–Pd dσ–dσ bonding orbital to the diene LUMO (Figure 6b). …”

Section: Resultsmentioning

confidence: 99%

Dipalladium(I) Terphenyl Diphosphine Complexes as Models for Two-Site Adsorption and Activation of Organic Molecules

et al. 2013

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Well-defined models for binding of organic molecules across two metal centers are relatively rare. A paraterphenyl diphosphine was employed to support a dipalladium(I) moiety. Unlike previously reported dipalladium(I) species, the present system provides a single molecular hemisphere for binding of ligands across two metal centers, enabling the characterization and comparison of the binding of a wide variety of saturated and unsaturated organic molecules. The dipalladium(I) terphenyl diphosphine toluene-capped complex was synthesized from a dipalladium(I) hexaacetonitrile precursor in the presence of toluene. The palladium centers display interactions with the π-systems of the central ring of the terphenyl unit and that of the toluene. Exchange of toluene for anisole, 1,3-butadiene, 1,3-cyclohexadiene, thiophenes, pyrroles, or furans resulted in well-defined π-bound complexes which were studied by crystallography, nuclear magnetic resonance (NMR) spectroscopy, and density functional theory. Structural characterization shows that the interactions of the dipalladium unit with the central arene of the diphosphine does not vary significantly in this series allowing for a systematic comparison of the binding of the incoming ligands to the dipalladium moiety. Several of the complexes exhibit rare μ2-η2:η2 or μ2-η2:η1 (O or S) bridging motifs. Hydrogenation of the thiophene and benzothiophene adducts was demonstrated to proceed at room temperature. The relative binding strength of the neutral ligands was determined by competition experiments monitored by NMR spectroscopy. The relative equilibrium constants for ligand substitution span over 13 orders of magnitude. This represents the most comprehensive analysis to date of the relative binding of heterocycles and unsaturated ligands to bimetallic sites. Binding interactions were computationally studied with electrostatic potentials and molecular orbital analysis. Anionic ligands were also demonstrated to form π-bound complexes.

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“…[34] The geometry of these clusters is controlled both by the ligand environment and the formal oxidation state of the involved palladium centers. In addition, linear [35,36] and butterfly-shaped [21,37] structures are known.…”

Section: Discussionmentioning

confidence: 99%

Formation of Transient Anionic Metal Clusters in Palladium/Diene‐Catalyzed Cross‐Coupling Reactions

Kolter

Koszinowski

2019

Chemistry A European J

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Despite their considerable practical value, palladium/1,3‐diene‐catalyzed cross‐coupling reactions between Grignard reagents RMgCl and alkyl halides AlkylX remain mechanistically poorly understood. Herein, we probe the intermediates formed in these reactions by a combination of electrospray‐ionization mass spectrometry, UV/Vis spectroscopy, and NMR spectroscopy. According to our results and in line with previous hypotheses, the first step of the catalytic cycle brings about transmetalation to afford organopalladate anions. These organopalladate anions apparently undergo SN2‐type reactions with the AlkylX coupling partner. The resulting neutral complexes then release the cross‐coupling products by reductive elimination. In gas‐phase fragmentation experiments, the occurrence of reductive eliminations was observed for anionic analogues of the neutral complexes. Although the actual catalytic cycle is supposed to involve chiefly mononuclear palladium species, anionic palladium nanoclusters [PdnR(DE)n]−, (n=2, 4, 6; DE=diene) were also observed. At short reaction times, the dinuclear complexes usually predominated, whereas at longer times the tetra‐ and hexanuclear clusters became relatively more abundant. In parallel, the formation of palladium black pointed to continued aggregation processes. Thus, the present study directly shows dynamic behavior of the palladium/diene catalyst system and degradation of the active catalyst with increasing reaction time.

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From mononuclear to multinuclear complexes of palladium containing unsaturated hydrocarbon ligands

Cited by 27 publications

References 74 publications

Synthesis, structure and photoluminescence of a novel palladium(I) compound: [Pd3(μ3-Cl)2(dppp)3][Pd2(μ2-Cl)3(PPh3)2](PPh3)2

Synthesis, structure and photoluminescence of a novel palladium(I) compound: [Pd3(μ3-Cl)2(dppp)3][Pd2(μ2-Cl)3(PPh3)2](PPh3)2

Dipalladium(I) Terphenyl Diphosphine Complexes as Models for Two-Site Adsorption and Activation of Organic Molecules

Formation of Transient Anionic Metal Clusters in Palladium/Diene‐Catalyzed Cross‐Coupling Reactions

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