Dimeric Palladium Complexes Research Articles

Arylsulfonylnitrene and arenesulfonyl azide complexes of palladium

Reaction of [Pd2Cl2(dppm)2] 1 with arenesulfonyl azides RSO2N3 in CH2Cl2 at ambient temperature resulted in the formation of dimeric palladium complexes with bridging arylsulfonylnitrene ligands [Pd2Cl2(dppm)2(µ-NSO2R)] 2 (R = phenyl a, 4-methylphenyl b, 4-nitrophenyl c, 2-nitrophenyl d, 2-naphthyl e or ferrocenyl f). According to their NMR spectra, complexes 2a–2f are typical A-frame adducts, which has been verified by single crystal X-ray diffraction studies on 2d–2f. The short N(1)–S(1) distances [1.541(3)–1.565(3) A] reflect the double bond character of these bonds and indicate a dπ–pπ interaction of the sulfur atom and the imido nitrogen atom. With 2-nitrobenzenesulfonyl azide a by-product was observed in a yield of 10–15%. Based on spectroscopic properties (1H and 31P NMR, IR) and elemental analysis, this compound contains a bridging arenesulfonyl azide ligand, [Pd2Cl2(dppm)2(µ-2-O2NC6H4SO2N3)] 3d. Irradiation with light of λ > 455 nm caused selective dissociation of 3d into 1 and 2-O2NC6H4SO2N3. The azide complex 3d is not an intermediate in the formation of the corresponding nitrene complex 2d.

Use of amido Grignard reagents in inorganic chemistry. Synthesis and crystal structure of anti-[Pd(Cl)(py)(μ-2,6-Pri2 C6H3NH)

F. Ragaini, S. Cenini and F. Demartin, J. Chem. Soc., Dalton Trans., 1997, 2855 DOI: 10.1039/A703853D

Synthesis and Characterization of Cationic Palladium (6,6‘-Dimethoxybiphenyl-2,2‘-diyl)bis(diphenylphosphine) Complexes

For compounds of the type [(MeO-BIPHEP)PdX2] (where MeO-BIPHEP is (6,6‘-dimethoxybiphenyl-2,2‘-diyl)bis(diphenylphosphine) and X is an anion with low coordination ability) one or both anions X, depending on their nature, are displaced in an outer coordination sphere due to water coordination. The compounds are easily reduced in methanolic solution. With the diaquo complex [{(S)-MeO-BIPHEP}Pd(H2O)2](OTf)2 as starting material, the formation of the dimeric palladium(I) complex [{(S)-MeO-BIPHEP}Pd]2(OTf)2 is observed. In contrast, under CO pressure, the μ-hydrido μ-carbonyl binuclear palladium(I) complex [{(S)-MeO-BIPHEP}Pd(μ-H)(μ-CO)Pd{(S)-MeO-BIPHEP}]OTf is formed. The molecular structures of [{(S)-MeO-BIPHEP}Pd(H2O)(THF)](OTf)2 and [{(S)-MeO-BIPHEP}Pd(OTfa)2] were determined by X-ray diffraction.

Palladium‐Catalyzed Reactions in Industry, 4[]. Synthesis of New Palladium Catalysts: First Isolation and Characterization of all Intermediates in a Cyclopalladation Reaction

AbstractIn order to synthesize chiral palladacycles for stereoselective C–C coupling reactions we studied the cyclopalladation of P‐chiral phosphanes 2 and 3. New palladium complexes of the type L2PdX2 (6, 8) and LXPd–μ‐X2–PdXL (5, 9, X = Cl; L = 2, 3) were isolated. A detailed study of the reactivity of all intermediates towards cyclopalladation proved the mechanism of cyclometalation reactions of o‐tolylphosphanes for the first time. Different deuteration experiments clearly demonstrated the higher reactivity of dimeric palladium complexes towards metalation compared to monomeric species. In agreement with this observation only 5 and 9 gave the cyclopalladated products 4 and 10 as revealed by FAB mass spectrometric investigations. Under the described reaction conditions the synthesis of the corresponding palladacycles 4, 10 is not possible because cyclometalation is a reversible process with LXPd–μ–X2–PdXL as thermodynamic more stable products. The results demonstrate the importance of free coordination sites on the metal atom for cyclometalation reactions or more general CH activation processes.

Palladium-catalyzed cross-coupling reactions between organic tellurides and alkenes

Diaryl tellurides, alkenyl aryl tellurides and dialkenyl tellurides react efficiently with various alkenes in methanol in the presence of a catalytic amount of PdCl 2 together with AgOAc and Et 3N to give the corresponding aryl- and alkenyl-substituted alkenes with moderate to quantitative yields. Both monomeric and dimeric palladium complexes, (Ph 2Te) 2PdCl 2 and [(Ph 2Te)PdCl 2] 2 respectively, react readily with alkenes to give a high yield of phenyl-substituted alkenes. The key step of this coupling reaction is proposed to be the migration of an organic moiety from Te to Pd (transmetallation) in organic tellurine-PdCl 2 complexes to afford organopalladium species.

Dinuclear Pd(I)−Pd(I) and Pt(II)···Pt(II) Complexes Supported by Tridentate Pyphos Ligands (Pyphos = 6-(Diphenylphosphino)-2-pyridonate)

Two dinuclear complexes of palladium(I) and platinum(II) have been prepared by using a tridentate ligand containing three kinds of coordination sites, i.e. oxygen, nitrogen, and phosphorus atoms. Treatment of palladium(II) acetate with a mixture of 6-(diphenylphosphino)-2-pyridone (abbreviated as PyphosH) and sodium methoxide in diglyme produced a dimeric palladium(I) complex containing a metal−metal bond, Pd2(pyphos)2(pyphosH)2 (1), in 43% yield. The dinuclear complex 1 has a Pd−Pd single bond [2.623(1) A] surrounded by two pyphos ligands and two pyphosH ligands, where the pyphos ligand connected to pyphosH through an intramolecular hydrogen bond [1: monoclinic, space group C2/c with a = 19.794(7) A, b = 14.753(7) A, c = 25.626(5) A, β = 107.65(2)°, V = 7131(4) A3, Z = 4, and R = 0.058 for 4760 reflections with I > 3σ(I) and 451 parameters]. In the case of platinum, a dinuclear platinum(II) complex, Pt2(pyphos)4 (3), was prepared in 84% yield by treatment of PtCl2(pyphosH)2 (2) with 2 equiv of sodium me...

ChemInform Abstract: Novel Bonding Modes in Monomeric and Dimeric Palladium and Platinum Complexes with Cyclopentadienyl Ligands

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Novel Bonding Modes in Monomeric and Dimeric Palladium and Platinum Complexes with Cyclopentadienyl Ligands

Cyclopentadienyl complexes of palladium and platinum undergo rearrangements from η5 to η1 coordination modes, and, in certain cases, displacement of the cyclopentadienide anion. This reactivity is carried over to diplatinum systems bridged by diphenylphosphinocyclopentadienyl ligands, where the ligand can adopt a range of bonding modes to accommodate the presence or absence of a metal-metal bond.

Structural Characterization and Simple Synthesis of {Pd[P(o-Tol)3]2}. Spectroscopic Study and Structural Characterization of the Dimeric Palladium(II) Complexes Obtained by Oxidative Addition of Aryl Bromides and Their Reactivity with Amines

Structural Characterization and Simple Synthesis of {Pd[P(o-Tol)3]2}. Spectroscopic Study and Structural Characterization of the Dimeric Palladium(II) Complexes Obtained by Oxidative Addition of Aryl Bromides and Their Reactivity with Amines

Reactions of Dimeric Palladium(I) Complexes with Sulfur-Substituted Acetylenes: 1,2-Heteroatomic Shift Reactions versus Adduct Formation. X-ray Crystal Structures of [Pd2Cl2(.mu.-dppm)2(.mu.-CH3SCCSCH3)].cntdot.CH2Cl2, [Pd2Cl2(.mu.-dmpm)2(.mu.-CH3SCCSCH3)], and [Pd2Cl2(.mu.-dppm)2(.mu.-.sigma.-C:C(CH3)(SCH3))

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTReactions of Dimeric Palladium(I) Complexes with Sulfur-Substituted Acetylenes: 1,2-Heteroatomic Shift Reactions versus Adduct Formation. X-ray Crystal Structures of [Pd2Cl2(.mu.-dppm)2(.mu.-CH3SCCSCH3)].cntdot.CH2Cl2, [Pd2Cl2(.mu.-dmpm)2(.mu.-CH3SCCSCH3)], and [Pd2Cl2(.mu.-dppm)2(.mu.-.sigma.-C:C(CH3)(SCH3))]Julian A. Davies, Kristin Kirschbaum, and Constanze KluweCite this: Organometallics 1994, 13, 9, 3664–3670Publication Date (Print):September 1, 1994Publication History Published online1 May 2002Published inissue 1 September 1994https://doi.org/10.1021/om00021a046RIGHTS & PERMISSIONSArticle Views71Altmetric-Citations16LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (800 KB) Get e-AlertsSupporting Info (1)»Supporting Information Supporting Information Get e-Alerts

(CN)-chelate, N,N'-bridged dimeric palladium complexes derived from hydrazones PhC(R):NN'HPh. X-ray structure of [Pd(o-C6H4C(R):NNPh)L]2 [R = Me, L = P(OMe)3

{Pd[C 6 H 4 C(Me)=NNPh][P(OMe) 3 ]}, C 34 H 42 N 4 O 6 P 2 Pd 2 , cristallise dans P2 1 /n avec a=13,477, b=19,546, c=14,231 A, β=97,43˚, Z=4; affinement jusqu'a R=0,057. Le cycle Pd 2 N 4 a une forme de papillon, avec une charniere le long des atomes N sans proton et une distance Pd-Pd de 3,788 A. Outre ce compose, d'autres complexes du palladium ont ete synthetises et la tendance a la coordination ou non de l'atome libre de l'amine etudiee

Carbonylation of aryl- and vinyl-tellurium compounds with carbon monoxide in the presence of palladium(II) salts

Aryl- and vinyl-tellurium(II or IV) compounds react with carbon monoxide (CO) in suitable organic solvents to give the corresponding carboylic acids in moderate to quantitative yields in the presence of a stoichiometric amount of a palladium(II) salt. Treatment of ( Z)-styrylphenyl telluride with atmospheric pressure of CO at room temperature in the presence of palladium(II) chloride or lithium chloropalladate(II) affords predominantly ( E)-cinnamic acid, while in the presence of palladium(II) acetate similar reaction gives the ( Z)-acid highly selectively. Under higher CO pressures (5–50 atm), however, the ( Z)-acid becomes the major product, even when palladium(II) chloride is used. The following pathways are proposed for this carbonylation: (1) in the first step organotellurium compounds form the monomeric and/or dimeric palladium complexes such as [(R 2Te)PdCl 2] 2 and/or (R 2Te) 2PdCl 2 (R = aryl, vinyl), then (2) the migration of R moiety from tellurium to palladium (transmetallation) occurs to afford the reactive aryl- or alkenyl-palladium compounds, and (3) the compounds react with CO to give the corresponding acylpalladium compounds, after alkaline hydrolysis, the carboxylic acids are formed. The presence of an ionic carbene-like organopalladium complex is proposed for the formation of the ( Z)-acid from ( Z)-telluride.

Cyclopalladation and cyclorhodation of N-(3-thienyl)pyrazole

N-(2-Thienyl)pyrazole (H(2-tpz)) gives the pyrazole- N-coordinated complex [PdCl 2(H(2-tpz)) 2] with palladium(II) chloride and N-(3-thienyl)pyrazole (H(3-tpz)) gives similarly [PdCl 2(H(3-tpz)) 2] and cyclopalladated [PdCl(3-tpz)] 2. The cyclopalladation occurs mainly at position 2 of the thiophene ring with a significant amount of the reaction at position 4 (ratio 3 : 1), contrary to lithiation which is reported to occur exclusively at position 2. H(3-tpz) is also metallated similarly by hexachlorotetrakis(tri-n-butylphosphine)dirhodium(III) to give [RhCl 2(PBu 3)(3-tpz)] 2. These dimeric palladium and rhodium complexes form adducts with pyridine and tri-n-butylphosphine.

Dimeric palladium (I) complexes containing the bridging cyclopentadienyl group

Dimeric palladium(I) complexes of the type [μ-(η 3-C 5H 5)-μ-XPd 2(PR 3) 2](X  Br, R  i-Pr, Ph, Cy; X  Cl, I, R  i-Pr) have been prepared by reduction of the complexes [(ν 5-C 5H 5)(PR 3)PdX] with a variety of reducing agents (Mg,Na/Hg, LiAlH(t-BuO) 3, LiAlH 4, NaBH 4, n-BuMgBr). PMR and IR data and some properties of the new complexes are reported.

Preparation and dynamic properties of some dimeric palladium(I) and platinum(I) complexes

Preparation and dynamic properties of some dimeric palladium(I) and platinum(I) complexes

ChemInform Abstract: TRANSFER OF TERTIARY PHOSPHINE BETWEEN RHODIUM AND EITHER PLATINUM OR PALLADIUM

AbstractDie quadratisch‐pyramidalen Rh(III)‐Komplexe (I) setzen sich mit den dirneren chlorverbrückten Pt(II)‐ und Pd(II)‐Komplexen (II) zu den‐chlorverbrückten Zweikernkomplexen (III) um.

Transfer of tertiary phosphine between rhodium and either platinum or palladium

Biheterometallic chloro-bridged hydrido-species of type [L2HClRh(µ-Cl)2MClL′](L = PButPr2 or PPrBut2, M = Pd or Pt, L′= PEt3, PBu3, or PPr2But) are formed on mixing toluene solutions of square-pyramidal [RhHCl2L2]2(L = PPr2But or PPrBut2) and a chloro-bridged dimeric palladium or platinum complex, [M2Cl4L′2](M = Pt, L′= PEt3, PBu3, or PPr2But; M = Pd, L′= PBu3). On standing, in solution, at ambient temperature these biheterometallic complexes decompose, giving rise to mixed tertiary-phosphine complexes of type trans-[MCl2LL′]. The rate of this reaction is strongly dependent on the nature of both M and L. The 1H and 31P n.m.r. data of the com-plexes are reported.

Polarised crystal spectra of some dimeric palladium(II) and platinum(II) halide complexes

Polarised transmission spectra are reported for single crystals of bistetraethylammonium hexabromo- and hexaiododipalladate(II) and the corresponding diplatinates. The known crystal structure of the hexabromodiplatinate(II) permits the resolution of the polarisation of the ligand-field transitions along the molecular axes and hence leads to assignments of the excited states. The relationship between the assignments for all four compounds and those for tetrachloroplatinate(II) and tetrachloropalladate(II) is discussed. There is no spectroscopic evidence for electronic interaction between the metal atoms in the dimeric anions.