- Structurally different mono-, bi- and trinuclear Pd(II) complexes and their DNA/protein interaction, DNA cleavage, and anti-oxidant, anti-microbial and cytotoxic studies
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A series of new structurally different Pd(ii) complexes was obtained by the reactions between K2[PdCl4], 3-methoxysalicylaldehyde-4(N)-substituted thiosemicarbazone [H2L1-H2L4] and bis(diphenylphosphino)ethane [dppe]. All the complexes were characterized by using various spectral techniques (IR, electronic, 1H-NMR and mass spectroscopy). The crystal structures of complexes 1, 3, 4 and 3a & 4a were determined using X-ray crystallographic technique. The interactions of the new complexes with calf thymus DNA (CT-DNA) and bovine serum albumin (BSA) were evaluated using various spectroscopic methods, which showed the interaction potential of the complexes with CT-DNA and BSA. Further, they cleaved supercoiled DNA pBR322. The anti-oxidant profiles of the complexes were found to be better than the standards against 2,2′-diphenyl-1-picrylhydrazyl radicals (DPPH) and superoxide anion radicals. The antibacterial activity of the complexes against five pathogenic bacteria such as Staphylococcus aureus, Salmonella typhi, Escherichia coli, Bacillus subtilis and Pseudomonas aeruginosa was found to be better than their parent ligands. The complexes exhibited potential cytotoxicity against human breast cancer cells (MCF-7) in the following order: 4 > 3 > 1 > cisplatin > 2.
- Shanmugapriya,Jain, Ruchi,Sabarinathan,Kalaiarasi,Dallemer,Prabhakaran
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- New alkoxycarbonyl complexes of palladium (II) and their role in carbonylation reactions carried out in the presence of an alkanol
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The new complexes of general formula trans-Pd(COOR)ClL2 =PPH3 R=Et, n-Pr, iso-Pr, n-Bu, iso-Bu, 2-ethoxyethyl, cyclopentyl, cyclohexyl; L=1,2-diphenylphosphinoethane, R=Et) are prepared reacting trans -PdCl2L2, suspended in an alkanol, under 10-50 atm of carbon monoxide, at 50-70°C, in presence of a base such as a trialkylamine or a carboxylic acid anion. They have been characterized by IR, 1H and 31P NMR spectroscopy. The complexes with R=Me and Et show two absorption bands centered at ca. 1650 cm-1, which are probably due to conformational isomers with cis and trans geometry. The other show only one band at ca. 1650 cm-1. The 1H NMR and 31P NMR spectra of all the monophosphine complexes show that only one isomer is present in solution. Instead, for the diphosphine ethoxycarbonyl complex the 1H NMR spectra suggest that two isomers are present, in the ratio of ca. 1:1, as confirmed by decoupling experiments. The two isomers may take origin from different orientation of the alkoxycarbonyl ligand with respect to the asymmetrical metal centre, because of hindered rotation around the Pd-C bond due to the partial double bond character. The R group of the alkoxycarbonyl ligand can be exchanged with a different R' group by reacting the Pd(COOR)Cl(PPh3)2 complex with an excess of R'OH. The reaction is practically quantitative when R is bulkier than R'. The alkoxycarbonyl complexes react with the corresponding alkanol, in the presence of a base such as a trialkylamine, at 90-100°C, under carbon monoxide, yielding Pd(0) carbonyl-phosphine complexes with formation of dimethyl carbonate in an almost quantitative yield. They react also with water giving off CO2 and yielding Pd(0) complexes. The reaction is promoted by an acid of a noncoordinating anion such as HBF4. Instead, the reaction with HCl yields the corresponding dichloride of Pd(II), beside carbon monoxide and the corresponding alkanol. The role of these complexes in catalytic alkoxycarbonylation reactions is discussed.
- Bertani, R.,Cavinato, G.,Toniolo, L.,Vasapollo, G.
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- PREPARATION AND REACTIONS OF HYDROXO-ENYLPALLADIUM(II) DERIVATIVES
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Some new hydroxo-enyl derivatives of palladium(II) of the type 2, and PF6 (C7H8 = norbornadiene, diene = norbornadiene or 1,5-cyclooctadiene; L-L = 2,2'-dipyridyl or 1,10-phenanthroline) have been made by nucleophilic attack of H2O on the diene coordinated to the metal in dispositively charged complexes.Evidence is presented to show that the hydroxonorbornenyl-1,2-bis(diphenylphosphino)ethane palladium(II) is involved as an intermediate, in an unusual example of oxidation of the alcoholic group through a palladium(II)-mediated intramolecular hydrogen transfer.
- Rotondo, Enrico,Priolo, Francesca Cusmano,Donato, Andrea,Pietropaolo, Rosario
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- ELECTROPHILIC ATTACK ON (2-NORBORNANONE)PALLADIUM(II) DICHLORIDE
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The protonolysis of the complex (2-norbornanone)palladium(II) chloride(I) has been studied.Comparison of the 13C NMR spectra of samples of 2-norbornanone obtained by treatment with HCl or DCl, unambiguously reveals that the carbon of the ketone was previously coordinated to the palladium(II).Kinetic results for the electrophilic cleavage of I are also reported.The rate law and the deuterium isotope effect suggest a rate-determining proton transfer to the palladium-carbon ?-bond, which takes place through a symmetrical three-centre transition state.
- Rotondo, E.,Cusmano, F. Priolo,Neri, G,Donato, A.,Pietropaolo, R.
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- The coordination chemistry of sulfonyl-substituted thioureas towards the d8 metal centres platinum(II), palladium(II), nickel(II) and gold(III)
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Reactions of the complexes cis-[PtCl2(PPh3)2], [PtCl2(dppp)] (dppp = Ph2P(CH2)3PPh2), [MCl2(dppe)] (dppe = Ph2P(CH2)2PPh2, M = Ni, Pd), [PdCl2(bipy)] (bipy = 2,2′-bipyridine) and [AuCl2(bp)] (bp = cyclometallated 2-benzylpyridine) with p-TolSO2NHC(S)NHPh and Et3N in refluxing methanol gave a series of new thiourea complexes containing the ligand bound as a dianion through the S and the NPh groups. The related thioureas RSO2NHC(S)NHPh (R = Me, Et) and p-TolSO2NHC(S)NHCH2CH=CH2 were also reacted with cis-[PtCl2(PPh3)2] to form the corresponding complexes [Pt{RSO2NC(S)NPh}(PPh3)2] and [Pt{TolSO2NC(S)NCH2CH=CH2}(PPh3)2] respectively. X-ray structure determinations were carried out on the thiourea MeSO2NHC(S)NHPh and its platinum complex [Pt{MeSO2NC(S)NPh}(PPh3)2], as well as [Pt{TolSO2NC(S)NPh}(PPh3)2]. Both complexes form the distal isomer with a remote NSO2R group, and no evidence was observed for isomerisation of these platinum complexes in solution. The palladium complexes [Pd{TolSO2NC(S)NPh}L2] [L2 = Ph2PCH2CH2PPh2 (dppe), or 2,2′-bipyridine (bipy)] undergo decomposition in solution to form the sulfide-bridged aggregates [Pd3S2(L2)3]2+, identified by ESI MS and 31P NMR.
- Henderson, William,Risi, Matthew C.,Saunders, Graham C.
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- Meso -Tetra-(4-pyridyl)porphyrin/palladium(ii) complexes as anticancer agents
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This study reports the synthesis, structural characterization and cytotoxic activity of four new palladium/pyridylporphyrin complexes, with the general formula {TPyP[PdCl(P-P)]4}(PF6)4, where P-P is 1,2-bis(diphenylphosphino)ethane (dppe), 1,3-bis(diphenylphosphino)propane (dppp), 1,2-bis(diphenylphosphino)butane (dppb) or 1,1′-bis(diphenylphosphino)ferrocene (dppf). The complexes were characterized by elemental analysis, and by FT-IR, UV/Vis, 1H and 31P{1H} NMR (1D/2D) spectroscopy. The slow evaporation of a methanolic solution of {TPyP[PdCl(dppb)]4}(PF6)4 (in an excess of NaBF4 salt) resulted in single crystals suitable for X ray diffraction, allowing the determination of the tridimensional structure of this complex, which crystallized in the P21/a space group. The cytotoxicity of the complexes against MDA-MB-231 (breast cancer cells) and MCF-10A (non-tumor breast cancer cells), was determined by the colorimetric MTT method, which revealed that all four complexes show selective indexes close to 1.2, lower than that of cisplatin for the same cells (12.12). The interaction of the complexes with CT-DNA was evaluated by UV-visible and viscosity measurements and it was determined that the complexes interact moderately with CT-DNA, probably by H-bonding/π-π stacking and electrostatic interactions. This journal is
- Alves, Kamilla M.,Ayalla, Alejando P.,Batista, Alzir A.,Dutra, Jocely De L.,Ellena, Javier,Gon?alves, Pablo J.,Guedes, Adriana P. M.,Honorato, Jo?o,Li?o, Luciano M.,Velozo-Sa, Vivianne S.
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p. 16254 - 16264
(2021/11/27)
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- Pyrrole thioamide complexes of the d8 metals platinum(II), palladium(II) and gold(III)
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Reactions of the cycloaurated gold(III) complexes [AuCl2(2-benzylpyridyl)] and [AuCl2(C6H4CH2NMe2)] with a set of pyrrole-2-thioamide ligands, containing various substituents on the pyrrole ring, gave a series of new gold(III) pyrrole thioamide complexes. X-ray crystal structures on two complexes indicate that the pyrrole thioamide ligand is coordinated through the deprotonated pyrrole nitrogen, as well as the sulfur atom of the deprotonated thioamide group, forming five-membered chelate ring complexes. In both complexes, the two highest trans-influence donor atoms (C and S) are mutually cis. Related sets of platinum(II) and palladium(II) pyrrole thioamide complexes were similarly prepared by reactions of cis-[PtCl2(PPh3)2] and [PdCl2(dppe)] (dppe = Ph2PCH2CH2PPh2)] respectively. The complexes were characterised by NMR and IR spectroscopies, and ESI mass spectrometry. A preliminary investigation of the activity of a selection of compounds towards A549 (adenocarcinomic human alveolar basal epithelial) cells was also carried out.
- Tang, Haiming,Saunders, Graham C.,Ma, Xiaochuan,Henderson, William
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- A group of diphosphine-thiosemicarbazone complexes of palladium: Efficient precursors for catalytic C–C and C–N coupling reactions
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Reaction of 4-R-benzaldehyde thiosemicarbazone (denoted in general as HL-R; where H stands for the dissociable acidic proton and R (R = OCH3, CH3, H, Cl and NO2) for the substituent) with [Pd(dppe)(EtOH)2]2+, generated in situ via interaction of [Pd(dppe)Cl2] (dppe = 1,2-bis(diphenylphosphino)ethane) with AgNO3 in hot ethanol, in the presence of triethylamine affords a group of orange complexes of the type [Pd(dppe)(L-R)]NO3. Structures of [Pd(dppe)Cl2] and [Pd(dppe)(L-OCH3)]NO3 have been determined by X-ray crystallography. In the [Pd(dppe)(L-R)]NO3 complexes, the thiosemicarbazone ligands are coordinated to the metal center as monoanionic bidentate N,S-donors forming five-membered chelate rings. The [Pd(dppe)(L-R)]NO3 complexes show intense absorptions in the visible and ultraviolet regions, which have been analyzed by TDDFT calculations. All the [Pd(dppe)(L-R)]NO3 complexes are found to efficiently catalyze Suzuki-type C–C and Buchwald-type C–N coupling reactions.
- Thapa, Kiran,Paul, Piyali,Bhattacharya, Samaresh
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p. 232 - 239
(2018/11/06)
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- Triphenylene based metal-pyridine cages
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C3-symmetric pyridine containing tris-benzyl-O-substituted hexahydroxytriphenylene derivatives were prepared and used in combination with square-planar Pd(II) and Pt(II) complexes for the self-assembly of molecular cages in solution. The formation of a trigonal bipyramid M3L2 cage was demonstrated by multinuclear NMR analyses and pseudo 2D DOSY experiments and supported by semi-empirical calculations.
- Berton, Giacomo,Lorenzetto, Tommaso,Borsato, Giuseppe,Sgarbossa, Paolo,Santo, Claudio,Visentin, Fabiano,Fabris, Fabrizio,Scarso, Alessandro
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supporting information
(2019/10/02)
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- A double (mortars; concrete ; artificial stone) alkane dichloride method for the preparation of palladium complexes (by machine translation)
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The invention discloses a double (mortars; concrete ; artificial stone) alkane second palladium chloride complex preparation method, the method is:a, preparation chlorine arrowhead acid solution; b, the double (mortars; concrete ; artificial stone) alkane adding N, N-dimethyl formamide (mortars; concrete ; artificial stone) is made of the alkane-N, N-dimethyl formamide solution; three, under stirring condition to the double (mortars; concrete ; artificial stone) N of paraffins, N-dimethyl formamide solution adds by drops the chlorine arrowhead acid solution, stirring reaction after the completion of the dropping, cooling after-filtration, the filter cake obtained; four, washing the filter cake, the filter cake after washing is then subjected to vacuum drying, to get double (mortars; concrete ; artificial stone) alkane second palladium chloride complex. The invention directly the palladium source is palladium sponge, to double with the ligand chlorine arrowhead acid (mortars; concrete ; artificial stone) alkane in the solvent DMF in one-step synthesis target product, omits the intermediate palladium chloride, palladium chloride process for the preparation of acetonitrile, has the advantages of simple technique, cycle is short, low cost, and the like. (by machine translation)
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Paragraph 0015; 0016; 0017; 0018; 0019
(2017/02/24)
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- A comprehensive mechanistic picture of the isomerizing alkoxycarbonylation of plant oils
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Theoretical studies on the overall catalytic cycle of isomerizing alkoxycarbonylation reveal the steric congestion around the diphosphine coordinated Pd-center as decisive for selectivity and productivity. The energy profile of isomerization is flat with diphosphines of variable steric bulk, but the preference for the formation of the linear Pd-alkyl species is more pronounced with sterically demanding diphosphines. CO insertion is feasible and reversible for all Pd-alkyl species studied and only little affected by the diphosphine. The overall rate-limiting step associated with the highest energetic barrier is methanolysis of the Pd-acyl species. Considering methanolysis of the linear Pd-acyl species, whose energetic barrier is lowest within all the Pd-acyl species studied, the barrier is calculated to be lower for more congesting diphosphines. Calculations indicate that energy differences of methanolysis of the linear versus branched Pd-acyls are more pronounced for more bulky diphosphines, due to involvement of different numbers of methanol molecules in the transition state. Experimental studies under pressure reactor conditions showed a faster conversion of shorter chain olefin substrates, but virtually no effect of the double bond position within the substrate. Compared to higher olefins, ethylene carbonylation under identical conditions is much faster, likely due not just to the occurrence of reactive linear acyls exclusively but also to an intrinsically favorable insertion reactivity of the olefin. The alcoholysis reaction is slowed down for higher alcohols, evidenced by pressure reactor and NMR studies. Multiple unsaturated fatty acids were observed to form a terminal Pd-allyl species upon reaction with the catalytically active Pd-hydride species. This process and further carbonylation are slow compared to isomerizing methoxycarbonylation of monounsaturated fatty acids, but selective.
- Roesle, Philipp,Caporaso, Lucia,Schnitte, Manuel,Goldbach, Verena,Cavallo, Luigi,Mecking, Stefan
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supporting information
p. 16871 - 16881
(2015/02/19)
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- Synthesis, characterization, thermal, electrochemical, and DFT studies of mononuclear cyclopalladated complexes containing bidentate phosphine ligands and their biological evaluation as antioxidant and antibacterial agents
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The non-symmetric phosphorus ylides and their Pd(II) complexes have been synthesized as potential antioxidant and antibacterial compounds and their structures were elucidated using a variety of physicochemical techniques. The reaction of 1 equiv non-symmetric phosphorus ylides, Ph2PCH 2PPh2C(H)C(O)PhX (X = Br (Y1), Cl (Y 2), NO2 (Y3), OCH3 (Y4)) with [Pd(dppe)Cl2] (M1), followed by treatment with 2 equiv AgOTf led to monomeric chelate complexes, [(dppe)Pd(Ph2PCH 2PPh2C(H)C(O)PhX)] (OSO2CF3) 2 (X = Br (C1), Cl (C2), NO2 (C 3), OCH3 (C4)), which contain a five-membered P,P chelate ring in one side and a five-membered P,C chelate ring in the other side. Palladium ion complexes were synthesized and investigated by cyclic voltammetry, FT-IR, UV-visible, multinuclear (1H, 31P and 19F) NMR, thermal analysis and ESI-mass spectroscopic studies. Some complexes and ligands have been studied by powder XRD and single crystal X-ray diffraction techniques. FT-IR and 31P NMR studies revealed that the ylides Y are coordinated to the metal ions via the terminal phosphorus (P c) of the ylides and methene group (CH). The proposed coordination geometry around the Pd atom in these complexes is defined as slightly distorted square planar by UV-Visible and DFT studies. Thermal stability of all complexes was also shown by TG/DTG methods. Furthermore, the electrochemical behavior of the complexes was investigated by cyclic voltammetry. The results indicate that all complexes are successfully synthesized from the initial ligands. All complexes were analyzed for their antioxidant properties by DPPH free radical scavenging assay. In addition, the antibacterial effects of the hexane-solved complexes were investigated by disc diffusion method against four Gram positive and negative bacteria. All complexes represented antibacterial activity against bacteria tested especially on Gram positive ones. A theoretical study on the structure, 1H and 31P NMR chemical shifts and the interaction energy between the Pd2+ ion and ligands dppe and ylide Y is also reported.
- Sabounchei, Seyyed Javad,Ahmadi, Mohsen,Nasri, Zahra,Shams, Esmaeil,Salehzadeh, Sadegh,Gholiee, Yasin,Karamian, Roya,Asadbegy, Mostafa,Samiee, Sepideh
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p. 159 - 175
(2013/06/05)
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- Five-membered cyclopalladated complex containing bidentate phosphine ligands; Synthesis, characterization, and highly efficient Suzuki cross-coupling reactions
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A nonsymmetric phosphorus ylide and its palladium(II) complex have been synthesized as potential catalytically active compounds. The reaction of 1 equiv nonsymmetric phosphorus ylide, Ph2PCH2PPh 2C(H)C(O)PhBr with [Pd(dppe)Cl2], followed by treatment with 2 equiv AgOTf led to [(dppe)Pd(Ph2PCH2PPh 2C(H)C(O)PhBr)](OSO2CF3)2, which contains a five-membered P,P chelate ring on one side and a five-membered P,C chelate ring on the other side. The palladium complex was synthesized and investigated by fourier transform infrared spectroscopy (FT-IR), UV-visible, multinuclear (1H, 31P and 19F) nuclear magnetic resonance (NMR), and electrospray ionisation-mass spectroscopic techniques. FT-IR and 31P NMR studies revealed that the phosphorus ylide is coordinated to palladium via the terminal phosphorus (Pc) of the ylide and methene group (CH). Suzuki reactions for varying aryl halides using the cyclopalladated complex as an efficient catalyst were performed. Various aryl halides were coupled with arylboronic acids in DMF, under air, in the presence of 0.001 mol% of the homogeneous catalyst to afford the corresponding cross-coupled products in good to excellent yields.
- Sabounchei, Seyyed Javad,Ahmadi, Mohsen,Nasri, Zahra
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p. 411 - 423
(2013/08/24)
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- Pd complexes with trans-chelating ligands composed of two pyridyl groups and rigid π-conjugated backbone
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1,2-Bis(2-pyridylethynyl)benzene derivatives, having two pyridyl groups and π-conjugated backbone, were prepared from the 1:2 Sonogashira reaction of 1,2-diiodobenzene with 2-alkynyl pyridines. The obtained ligands react with the palladium(II) complexes such as [PdCl2(cod)] and [PdCl 2(MeCN)2] to form the complexes with the ligands coordinated in a trans-chelating bidentate mode. The ligand obtained from 1,3-diiodobenzene and 2-alkynyl pyridine bridges two Pd(II) centers, yielding a dipalladium complex. A dichloropalladium complex with the trans-chelating ligand, containing two methoxy groups in the central arylene group, promotes coupling of phenyl lithium and of phenyl acetylene to yield the respective homo-coupling products. The ligand displacement reactions of {bis(2-pyridylethynyl)benzene}palladium(II) complex with phosphine and dinitrogen ligands, such as PPh3, dppe, dppb, en, tmeda, bpy and phen, takes place smoothly to release the trans-chelating ligand.
- Jung, Miso,Suzaki, Yuji,Saito, Takashi,Shimada, Kyoichi,Osakada, Kohtaro
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p. 168 - 174
(2012/08/28)
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- HL2[(1,2-O2C6H4)3] (L = DMSO or DMF): A convenient proton source with a weakly basic phosphorus(V) Anion
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Treating phosphorus pentachloride with catechol (3 equiv) followed by the addition of dimethyl -sulfoxide (DMSO) or dimethylformamide (DMF) affords isolable Bronsted acids of the tris-(o-phenylenedioxy)phosphate anion, [P(1,2-O2C6Hs
- Siu, Paul W.,Gates, Derek P.
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p. 4491 - 4499
(2009/12/06)
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- PdII-promoted [2 + 3] cycloaddition of pyrroline N-oxide to organonitriles. Application of (Δ4-1,2,4-oxadiazoline)-Pd II complexes in the Suzuki-Miyaura reaction
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[2 + 3] Cycloaddition reactions of the organonitriles RCN 1 (R = Me (1a), Et (1b), p-IC6H4 (1c), p-BrC6H4 (1d), p-ClC6H4 (1e), p-FC6H4 (1f)) with the pyrroline N-oxide
- Lasri, Jamal,Da Silva, M. Fatima C. Guedes,Kopylovich, Maximilian N.,Mukhopadhyay, Suman,Charmier, M. Adilia Januario,Pombeiro, Armando J. L.
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p. 2210 - 2216
(2009/09/30)
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- Variable bonding modes of pyrimidine-2-thione in PdII/Pt II complexes [M(η2-N, S-pymS)(η1-S- pymS)(PPh3)] and [M(η1-S-pymS)2(L-L)] (L-L = dppm, dppe)
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Reactions of pyrimidine-2-thione (HpymS) with PdII/Pt IV salts in the presence of triphenyl phosphine and bis(diphenylphosphino) alkanes, Ph2P-(CH2) m-PPh2 (m = 1, 2) have yielded two types of complexes, viz. (a) [M(η2-N, S- pymS)(η1-S- pymS)(PPh 3)] (M = Pd, 1; Pt, 2), and (b) [M(η1-S-pymS) 2(L-L)] {L-L, M = dppm (m = 1) Pd, 3; Pt, 4; dppe (m =2), Pd, 5; Pt, 6}. Complexes have been characterized by elemental analysis (C, H, N), NMR spectroscopy (1H, 13C, 31P), and single crystal X-ray crystallography (1, 2, 4, and 5). Complexes 1 and 2 have terminal η1-S and chelating η2-N, S-modes of pymS -, while other Pd/Pt complexes have only terminal η1-S modes. The solution state 31P NMR spectral data reveal dynamic equilibrium for the complexes 3, 5 and 6, whereas the complexes 1, 2 and 4 are static in solution state.
- Lobana, Tarlok S.,Kaur, Parminderjit,Hundal, Geeta,Butcher, Ray J.,Castineiras, Alfonso
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p. 747 - 753
(2009/04/13)
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- Pyridine-2-thionate as a versatile ligand in Pd(ii) and Pt(ii) chemistry: The presence of three different co-ordination modes in [Pd2(μ 2-S,N-C5H4SN)(μ2- κ2S-C5H4SN)(μ2-dppm) (S-C5H4SN)2]
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Reactions of [MCl2(L-L)], M = Pt, Pd; L-L = bis(diphenylphosphino)methane (dppm) or bis(diphenylphosphino)ethane (dppe), with NaC5H4SN in a 1: 2 molar ratio lead to mononuclear species [M(S-C5H4SN)2(P-P)], M = Pt; L-L = dppm (1) or dppe (2) and M = Pd; L-L = dppe (3), as well as to the dinuclear [Pd2(μ2-S,N-C5H4SN) (μ2-κ2S-C5H4SN) (μ2-dppm)(S-C5H4SN)2] (4). In contrast, reaction of [MCl2(dppm)] with NaC5H 4SN in a 1: 1 molar ratio leads to [Pd2(μ2- S,N-C5H4SN)3(μ2-dppm)]Cl (5) and trans-[Pt(S-C5H4SN)2(PPh2Me) 2] (6) respectively. The latter is formed in low yield by cleavage of the dppm ligand. The dinuclear derivatives 4 and 5 present an A-frame and lantern structure, respectively. The former showing three different co-ordination modes in the same molecule with a short Pd-Pd distance of 2.9583 (9) A and the latter with three bridging S,N thionate ligands showing a shorter Pd-Pd distance of 2.7291 (13) A. Both distances could be imposed by the bridging ligands or point to some sort of metal-metal interaction. The Royal Society of Chemistry 2006.
- Mendia, Aranzazu,Cerrada, Elena,Arnaiz, Francisco J.,Laguna, Mariano
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p. 609 - 616
(2007/10/03)
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- Stereoselective preparation, structures, and reactivities of phosphine-bridged mixed-metal trinuclear and pentanuclear complexes with tris[2-(diphenylphosphino)ethyl]phosphine
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The phosphine-bridged linear trinuclear and pentanuclear complexes with Pd(II)-Pt(II)-Pd(II), Ni(II)-Pt(II)-Ni(II), and Rh(III)-Pd(II)-Pt(II)-Pd(II)- Rh(III) metal-ion sequences were almost quantitatively formed by the stepwise phosphine-bridging reaction of the terminal phosphino groups of tris[2-(diphenylphosphino)ethyl]phosphine (pp3), which is the tetradentate bound ligand of the starting Pd(II) and Ni(II) complexes. The solid-state structures of the trinuclear complexes were determined by X-ray structural analyses, and the structures of the polynuclear complexes in solution were characterized by NMR spectroscopy. The trans and cis isomers of the trinuclear and pentanuclear complexes, which arise from the geometry around the Pt(II) center, were selectively obtained simply by changing the counteranion of the starting complexes: the tetrafluoroborate salts, [MX(pp3)] (BF4) [M = Pd(II) or Ni(II), X = Cl- or 4-chlorothiophenolate (4-Cltp-)], gave only the trans isomers, and the chloride salt, [PdCl(pp3)]CI, gave only the cis isomers. The formation of the trinuclear complex with the 4-Cltp- and chloro ligands, trans-[Pt(4-Cltp)2-{PdCl(pp3)} 2](BF4)2, proceeded with exchange between the thiolato ligand in the starting Pd(II) complex, [Pd(4-CltP)(pp 3)](BF4), and the chloro ligands in the starting Pt(II) complex, trans-[PtCl2(NCC6H5)2], retaining the trans geometry around the Pt(II) center. In contrast, the formation reaction between [PdCl(pp3)]Cl and trans-[PtCl 2(NCC6H5)2] was accompanied by the trans-to-cis geometrical change on the Pt(II) center to give the trinuclear complex, cis-[PtCl2{PdCl(pp3)}2]Cl2. The mechanisms of these structural conversions during the formation reactions were elucidated by the 31P NMR and absorption spectral changes. The differences in the catalytic activity for the Heck reaction were discussed in connection with the bridging structures of the polynuclear complexes in the catalytic cycle.
- Aizawa, Sen-Ichi,Saito, Kenji,Kawamoto, Tatsuya,Matsumoto, Emi
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p. 4859 - 4866
(2008/10/09)
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- Intermolecular Phenyl Ligand Transfer of Pt(II) and Pd(II) Complexes with Bidentate Ligand
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[PtPh2(dppe)] (dppe = 1,2-bis(diphenylphosphino)ethane) reacts with equimolar [PtCl2(cod)] (cod = 1,5-cyclooctadiene) to give a mixture of [PtPh2(cod)] (38%), [PtCl(Ph)(cod)] (53%) and [PtCl 2(dppe)] (72%) via exchange of the phenyl and chloro ligands among the Pt complexes. The reaction is strongly inhibited by addition of Cl -. The intermolecular phenyl ligand transfer from Pd to Pt is observed in the reaction of [PdCl(Ph)(bpy)] (bpy = 2,2′-bipyridine) with [PtX2(cod)] (X = Cl, I), which produces [PtX(Ph)(cod)]. The reaction of [PdCl(Ph)(bpy)] with [PdCl2(cod)], giving [Pd2(μ -Cl)2 {(4,5-η-κC1)-(C8H 12Ph)}2], occurs much faster than a similar reaction of [PdCl(Ph)(bpy)] with [PtCl2(cod)]. [PtPh2(L2)] (L2 = cod, dppe) reacts with [PdCl2(cod)] in CH 2Cl2 at room temperature to afford [Pd2(μ -Cl)2{(4,5-η-κC1)-(C8H 12Ph)}2] via intermolecular phenyl ligand transfer from Pt to Pd and subsequent insertion of a C=C bond of cod into the Pd-Ph bond. Cationic Pd complexes [Pd(acetone)2(cod)]2+(BF 4-)2 and [Pd(η3-C 3H5)(acetone)2]+(BF4-) react with [PtPh2(cod)] to form biphenyl. All these results indicate that chloro complexes of Pd and Pt with cod ligand undergo the ligand exchange with the phenyl complexes of these metals.
- Suzaki, Yuji,Osakada, Kohtaro
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p. 139 - 145
(2007/10/03)
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- Transition metal complexes containing P(C6H5)(C6H4Cl-2)2. The effect of added Lewis bases as a probe for substitution reactions occurring in ambient temperature Suzuki couplings catalyzed by Pd/P(C6H5)(C6H4Cl-2)2
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The reactivity of the d8 transition metal complexes, [NiBr2(CH3OCH2CH2OCH 3)] and MCl2L2 (M=Pd, Pt; L=CH3CN; L2=1,5-cyclooctadiene), towards P(C6H5)(C6H4Cl-2)2 (1) was investigated. While treatment of [PdCl2(cod)] with 2 equiv of 1 resulted in displacement of the weakly coordinating cyclooctadiene and formation of [PdCl2(P(C6H5)(C6H 4Cl-2)2)2], analogous reactions with [PtCl2(cod)] afforded the monosubstituted species [PtCl2(cod)(P(C6H5)(C6H 4Cl-2)2)]. The disubstituted complex [PtCl2(P(C6H5)(C6H 4Cl-2)2)2] was successfully obtained by treatment of [PtCl2(NCCH3)2] with 2 equiv of 1. However, attempts to react 1 with [NiBr2(CH3OCH2CH2OCH 3)] were unsuccessful. The chlorinated triphenyl phosphine is quite labile and is readily displaced from [PdCl2(P(C6H5)(C6H 4Cl-2)2)2] by various Lewis bases including nitrogen containing ligands such as 2,2′-bipyridine. The molecular structure of trans-[PdCl2(P(C6H5)(C6H 4Cl-2)2)2] was determined by X-ray diffraction and represents the first molecular structure determination of a transition metal complex containing 1. This complex crystallizes in the monoclinic space group P21/n with a=10.3928(3) ?, b=16.0102(4) ?, c=13.1884(4) ?, β=90.714(2)°, and Z=4. Key geometric parameters include Pd-Cl(1)=2.309(1) ?, Pd-P(1)=2.334(1) ?; Pd-P(1)-C(7)=118.3(2)°, Pd-P(1)-C(1)=115.3(2)°, C(1)-C(6)-Cl(2)=120.7(4)° and Cl(1)-Pd-P(1)=85.86(4)°.
- Stone, Joshua J.,Stockland Jr., Robert A.,Rath, Nigam P.
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p. 236 - 240
(2008/10/08)
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- Self-assembly and anion encapsulation properties of cavitand-based coordination cages
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Two novel classes of cavitand-based coordination cages 7a-j and 8a-d have been synthesized via self-assembly procedures. The main factors controlling cage self-assembly (CSA) have been identified in (i) a P-M-P angle close to 90° between the chelating ligand and the metal precursor, (ii) Pd and Pt as metal centers, (iii) a weakly coordinated counterion, and (iv) preorganization of the tetradentate cavitand ligand. Calorimetric measurements and dynamic 1H and 19F NMR experiments indicated that CSA is entropy driven. The temperature range of the equilibrium cage-oligomers is determined by the level of preorganization of the cavitand component. The crystal structure of cage 7d revealed the presence of a single triflate anion encapsulated. Guest competition experiments revealed that the encapsulation preference of cages 7b,d follows the order BF4- > CF3SO3- ? PF6- at 300 K. ES-MS experiments coupled to molecular modeling provided a rationale for the observed encapsulation selectivities. The basic selectivity pattern, which follows the solvation enthalpy of the guests, is altered by size and shape of the cavity, allowing the entrance of an ancillary solvent molecule only in the case of BF4-.
- Fochi,Jacopozzi,Wegelius,Rissanen,Cozzini,Marastoni,Fisicaro,Manini,Fokkens,Dalcanale
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p. 7539 - 7552
(2007/10/03)
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- Reaction of di-μ-dichloro-bis(N,N-dimethylbenzylamine-C2,N)dipalladium(II) with diphosphines. Six-membered ring complexes bearing spiro rings
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Reactions of [Pd(C6H4CH2NMe2-C2,N)(μ-Cl)]2 with diphosphines (diphos) such as dppf (a), dpmf (b), dppm (c), dppe (d) and dppp (e) gave [PdCl(C6H4CH2NMe2-C2,N)]2(μ-diphos) (2). Complexes 2 (a, b, d and e) reacted with NaPF6 to produce chelate complexes [Pd(C6H4CH2NMe2-C2,N)(diphos-P,P')][PF6] (3), whereas 2c gave a six-membered ring complex [Pd2(C6H4CH2NMe2-C2,N)2(μ-Cl)(μ-dppm)][PF6] (4c) bearing two exocyclic rings shared by each palladium atom. This complex was regenerated to 2c by treatment with [NEt3(CH2Ph)]Cl. Treatment of 3 (a, d and e) with one equiv. of aq. HCl caused protonation at the coordinate nitrogen atom to yield [Pd(C6H4CH2NHMe2-C2)(Cl)(diphos-P,P')][PF6] (5) (a, d and e). Reaction of 4c with aq. HCl in a 1:1 molar ratio led to protonation at one C-N chelating ring to give [Pd2(Cl)(C6H4CH2NMe2-C2,N)(C6H4CH2NHMe2-C2)(μ-Cl)(μ-dppm)][PF6] (6c). The structures of 2a, 3e, 4c, 5a and 6c were confirmed by X-ray analyses. (C) 2000 Elsevier Science S.A.
- Ma, Jian-Fang,Yamamoto, Yasuhiro
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p. 164 - 171
(2008/10/08)
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- Halide-Bridged Palladium(II) Dimers of Orthometalated (S)-(+)-N,N-Dimethyl-α-methylbenzylamine and (S)-(+)-N,N-Dimethyl[1-(2-naphthyl)ethyl]amine: Solution and Solid-State Structures and Reactions with 3,4-Dimethyl-1-phenylphosphole and Allyldiphenylphosphine
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Activation thermodynamics for the cis - trans isomerization of the chloride-, bromide-, and iodide-bridged palladium(II) dimers of orthometalated (S)-(+)-N,N-dimethyl-α-methylbenzylamine (TMBA) and (S)-(+)-N,N-dimethyl[1-(2-naphthyl)-ethyl]amine (TMNA) have been determined by variable-temperature 1H NMR spectroscopy. The chloride-bridged dimers are cleaved regioselectively by 3,4-dimethyl-1-phenylphosphole (DMPP) and allyldiphenylphosphine (ADPP) to form the mononuclear products {Pd(C6H4CH(Me)NMe2(R3P)Cl} and {Pd(C10H6CH(Me)NMe2(R3P)Cl} (R3P = DMPP, ADPP), with the phosphine exclusively trans to nitrogen. The chloride-bridged dimers react with NaPF6 or AgClO4, DMPP, and CH3CN to produce {Pd(C6H4CH(Me)NMe2(DMPP)(CH3CN)}X and {Pd(C10H6CH(Me)NMe2(DMPP)(CH3-CN)}X (X = PF6-, ClO4-). They react with NaPF6 or AgClO4 and excess DMPP to form [Pd-(DMPP)4](X)2 (X = PF6-, ClO4-). When X = PF6-, this complex undergoes two thermal [2+2] dimerizations of the coordinated DMPP ligands in the solid state to form {Pd(DMPP2-[2+2])2}(PF6)2. The complex {Pd(C10H6CH(Me)NMe2(DMPP)Cl} reacts with AgClO4 and ADPP at 75°C to form an unusual chloride-bridged tetrapalladium(II) macrocycle that contains a novel tridentate ligand with bridging phosphide and terminal R3P and C(-) donors. New complexes were characterized by elemental analyses, physical properties, infrared spectroscopy, polarimetry, and 1H, 1H{31P}, 13C{1H}, and 31P{1H} NMR spectroscopy and in most cases by X-ray crystallography.
- Guel, Nizamettin,Nelson, John H.
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- Five- and six-membered palladacycles derived from [(η5-C5H5)Fe{(η5-C 5H4)-CH=N-(C6H4-2-C 6H5)}]
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The reaction of the novel ferrocenyl Schiff base: [(η5-C5H5)Fe{(η5-C 5H4)-CH=N-(C6H4-2-C 6H5)}] (1) with Na2[PdCl4] and Na(CH3COO)·3H2O in a 1:1:1 molar ratio in methanol is reported. In this reaction two different di-μ-chloro-bridged cyclopalladated complexes: [Pd{[(η5-C5H3)-CH=N-(C6H 4-2-C6H5)]Fe(η5-C 5H5)}(μ-Cl)]2 (2a) and [Pd{[(C6H4-2-C6H4)-N=CH-(η 5-C5H4)]Fe(η5-C 5H5)}(μ-Cl)]2 (2b) can be formed depending on the experimental conditions. Compounds 2a and 2b, which differ in the nature of the metallated carbon atom (Csp2,ferrocene or Csp2,biphenyl, respectively), undergo cleavage of the 'Pd(μ-Cl)2Pd' bridges in the presence of thallium (I) acetylacetonate, deuterated pyridine or triphenylphosphine giving the monomeric derivatives: [Pd(C∧N)(acac)] (3a, 3b) and [Pd(C∧N)Cl(L)] {with L=py- d5(4a, 4b), PPh3(5a, 5b)}. The reactions of 2 with 1,2-bis(diphenylphosphino)ethane (dppe) reveal that the two isomers (2a and 2b) exhibit different reactivity versus dppe. These results have been interpreted on the basis of steric effects. Elsevier Science Ltd.
- Benito, Monica,Lopez, Concepcion,Morvan, Xavier
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p. 2583 - 2595
(2008/10/09)
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- Metal ion mediated transfer and cleavage of diaminocarbene ligands
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Under mild conditions, reactions of (CO)5M=C[N(R)CH2]2 [M = W, Mo, Cr; R = Et, allyl, benzyl, 4-pentenyl] with (PhCN)2PdCl2, (PhCN)2PtCl2, [(CO)2RhCl]2, (Me2S)AuCl, [(CH3-CN)4Cu]BF4, and AgBF4 provide the corresponding diaminocarbene complexes via carbene ligand transfer. The resulting Pd(II), Pt(II), Rh(I), and Au(I) carbene complexes are stable and were isolated. The Cu(I) and Ag(I) complexes readily undergo acid-induced M=C cleavage to yield the imidazolidin-2-ylidinium salts. The carbene-transfer reactions were studied for two phosphine donors: (CO)m(L)W=C[N(R)CH2]2 {R = Et, benzyl; L = PPh3, m = 4; L = dppe, m = 3}. The X-ray crystal structures of (CO)5W=C[N(CH2C6H5)CH 2]2 (1c), cis-(CO)4-(PPh3)W=C[N(CH2C6H 5)CH2]2 (5b), fac-(CO)3(dppe)W=C[N(CH2C6H5)CH 2]2 (6b), Cl2(CO)-Pt=C[N(CH2C6H5)CH 2]2 (9c), and cis-Cl2Pt{=C[N(CH2C6H5)CH 2]2}2 (11b) are reported.
- Ku, Rong-Zhi,Huang, Jen-Chung,Cho, Jian-Yang,Kiang, Fu-Mei,Reddy, K. Rajender,Chen, Yi-Chun,Lee, Kuo-Jeng,Lee, Jung-Hua,Lee, Gene-Hsiang,Peng, Shie-Ming,Liu, Shiuh-Tzung
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p. 2145 - 2154
(2008/10/08)
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- Practical Synthesis of Palladium Bis(trifluoromethanesulfonate) and Its Application to the Synthesis of Palladium Complexes
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Palladium bis(trifluoromethanesulfonate) is usually prepared from the reaction of palladium dinitrate or diacetate and trifluoromethanesulfonic acid. Reactions of palladium bis(trifluoromethanesulfonate) with various ligands (L and/or X-) give
- Murata, Shizuaki,Ido, Yoshiyuki
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p. 1746 - 1748
(2007/10/02)
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- Reactivity of palladium(II) complexes with bidentate bis(phosphine) ligands toward the octahydrotriborate(1-) anion and dependence of the reaction upon halide arrangement: Molecular structure of the trans-(bis(diphenylphosphino)hexane)palladium(II) dichloride dimer
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The reactivity of the palladium(II) bis(phosphine) complexes, (Ph2P(CH2)nPPh2)PdCl2 (n = 1-6), toward the octahydrotriborate(1-) anion, [B3H8]-, has been investigated. For n = 1-4, the metallaborane (Ph2P(CH2)nPPh2)Pd(B 3H7) is produced, although the yield depends upon the organic chain length of the phosphino ligand and is maximized when n = 2. Our observation that no reaction occurs between the [B3H8]- anion and (bis(diphenylphosphino)pentane)- or (bis(diphenylphosphino)hexane)-palladium(II) dichloride leads us to examine the structure of these starting materials. Unlike (Ph2P(CH2)nPPh2)PdCl2 for n = 1-4, which are cis monomers, complexes with n = 5 or 6 are dimeric with a trans arrangement of chloro substituents; the molecular structure of trans-[(Ph2P(CH2)6PPh2)PdCl 2]2 is presented: triclinic, P1; a = 9.448 (2), b = 11.772 (2), c = 16.983 (3) ?; α = 74.18 (2), β = 87.14 (2), γ = 77.59 (2)°; V = 1774.9 (9) ?3, Z = 2; RF = 5.17%. A detailed comparison of this structure with those of related complexes is made.
- Housecroft, Catherine E.,Shaykh, Bilal A. M.,Rheingold, Arnold L.,Haggerty, Brian S.
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p. 125 - 130
(2008/10/08)
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- Cleavage reactions of halogen-bridged heterobimetallic palladium-platinum complexes. Crystal and molecular structure of [(P-n-Bu3)Cl2Pd(t-BuN=CHCH=N-t-Bu)PtCl 2(P-n-Bu3)]
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Cleavage reactions of dichloro-bridged species [(P-n-Bu3)ClPd(μ-Cl)2PtCl(P-n-Bu3)] (I) with nitrogen-containing ligands (e.g. 4-cyanopyridine) and a variety of bis(phosphines) generally give mixtures of mononuclear products. However, reactions of I with bis(1-pyrazolyl)methane or with N,N′-dialkyl-1,2-diiminoethanes preserve the 1:1 Pd:Pt ratio and apparently give bridged heterobimetallic products. Crystals of the reaction product of I with t-BuN=CHCH=N-t-Bu, with a composition corresponding to [(P-n-Bu3)ClPd(t-BuN=CHCH=N-t-Bu)PtCl(P-n-Bu3)], are monoclinic, space group P21/n, with a = 11.454 (4) A?, b = 16.026 (4) A?, c = 12.909 (3) A?, and β = 99.91 (2)°. With Z = 2, the molecules must lie about inversion centers, and the Pd and Pt atoms are mutually disordered. The structure was solved by the heavy-atom method and refined by full-matrix least-squares calculations with anisotropic thermal parameters; R = 0.044 and Rw = 0.047 for 2707 reflections. The geometry around the metal atom is distorted square planar with M-P = 2.230 (2) A?, M-Cl = 2.295 (2) A?, and M-N = 2.135 (5) A?. The data are consistent with the preservation of a 1:1 Pd:Pt ratio in this product of a Pd(μ-Cl)2Pt bridge cleavage reaction.
- Clark, Howard C.,Ferguson, George,Jain, Vimal K.,Parvez, Masood
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p. 3808 - 3811
(2008/10/08)
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- 31P and 13C solid-state NMR of tertiary phosphine-palladium complexes bound to silica
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Phosphorus-31 and carbon-13 NMR spectra with cross polarization and magic-angle spinning are used to characterize palladium-tertiary phosphine complexes and their precursors covalently bound to silica. Phosphorus-31 NMR is a good probe of complex formation and geometry, whereas 13C NMR is a good probe of ligand structure. The 36.44-MHz 31P spectrum of (≡SiOSiCH2CH2PPh2)2PdCl 2 shows two, barely resolved peaks at about 21 and 30 ppm assigned to the trans and cis complexes, respectively. These assignments are based on the chemical shifts of model compounds in both solution and the solid state. Uncomplexed phosphine and phosphine oxide are observed when complexes are prepared from phosphinated silica but not when the complexes are preformed and then attached to silica. The palladium dichloride complexes of bis(diphenylphosphino)methane, -ethane, and -propane, all of which have an approximately square-planar configuration, were examined as solid-state models for strained cis complexes on the silica surface. As in solution, the solid-state 31P chemical shifts of these compounds occur over a range of 127 ppm while the P-Pd-P angle varies from 73 to 91°. Hence, the 31P chemical shift is a very sensitive measure of strain in such complexes and confirms that the structures in solution are similar to those in the solid state. Applying these models, we find that the surface-bound complexes have mainly unstrained, trans configurations. Other species that have been examined on surfaces or as models include (dicyclohexylpropyl)phosphino complexes, for which cis and trans surface-bound complexes are observed, trimethylsilyl-capped samples, and phosphine oxides. Evidence is found for hydrogen bonding between bound phosphine oxide groups and silanol groups on the silica surface. Both the chemical shift anisotropy powder pattern and P-H cross-polarization rates indicate that the Pd-phosphine complex is rigidly bound to the silica surface.
- Komoroski, Richard A.,Magistro, Angelo J.,Nicholas, Paul P.
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p. 3917 - 3925
(2008/10/08)
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- Photochemical generation of bis(phosphine)palladium and bis(phosphine)platinum equivalents
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Ultraviolet irradiation of oxalato bis(tertiary phosphine) complexes of platinum(II) and palladium(II), Pt(C2O4)L2 and Pd(C2O4)L2, results in the reductive elimination of the oxalate ligand
- Paonessa, Ralph S.,Prignano, Andrea L.,Trogler, William C.
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p. 647 - 657
(2008/10/08)
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- Bis(arylazo-oximato)palladium(II); Synthesis, Palladium-Nitrogen Bond Lability, and Redox Activity
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The synthesis and characterisation of the title complex, , and related mixed-ligand complexes including (A = ortho-metallated azobenzene) are described.The mass spectrum of reveals peaks corresponding to loss of oximato-O and NO from the parent ion.Gaseous HCl cleaves the Pd-N(oxime) bond selectively.Triphenylphosphine cleaves one or both Pd-N(azo) linkages giving and unstable which is also produced by oxidative addition of HL to .In the unidentate and bidentate L groups scramble rapidly at 308 K but slowly at 233 K (1H n.m.r.).Bidentate phosphine and phosphinoarsine cleave the two Pd-N(azo) bonds simultaneously.Unidentate amines, when present in very large excess, produce unstable in which one L is unidentate.Addition of X2 (X= Cl or Br) yields the unstable palladium(IV) complex which is readily reduced to halogeno-bridged palladium(II) species.A cyclic-voltammetric study of the one-electron quasi-reversible reduction of , , etc. at a platinum electrode is briefly reported.
- Bandyopadhyay, Pinaki,Mascharak, Pradip K.,Chakravorty, Animesh
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p. 623 - 627
(2007/10/02)
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- Selective Cleavage of the Two Types of Pd-N Bonds in Di-μ-halogeno-bis
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Triarylphosphines split the halogen bridge of the title complex and also open the arylazo-oximato chelate ring at the azo-end.In solution an equilibrium exists between the closed-ring and open-ring species.The equilibrium constants are reported.Bidentate phosphine and phosphinoarsine simultaneously split the bridge and cleave the Pd-N(azo) bond.Anhydrous HCl gas protonates the oximato-group with its concomitant displacement by Cl-ion; in effect the Pd-N(oxime) bond is selectively cleaved.
- Mascharak, Pradip K.,Chakravorty, Animesh
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p. 1698 - 1702
(2007/10/02)
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- Synthesis and Chemistry of Some Palladacyclopentanes
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The palladacyclopentane complexes have been prepared by reaction of the corresponding dichlorides with an ether solution of 1,4-dilithiobutane.Comp
- Diversi, Pietro,Ingrosso, Giovanni,Lucherini, Antonio,Murtas, Stefania
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p. 1633 - 1637
(2007/10/02)
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