Xn:Harmful;
7440-05-3Relevant articles and documents
Kinetically controlled synthesis of triangular and hexagonal nanoplates of palladium and their SPR/SERS properties
Xiong, Yujie,McLellan, Joseph M.,Chen, Jingyi,Yin, Yadong,Li, Zhi-Yuan,Xia, Younan
, p. 17118 - 17127 (2005)
The rapid reduction of Na2PdCl4 by ethylene glycol in the presence of poly(vinyl pyrrolidone) (PVP) has recently been demonstrated as a convenient method of generating Pd cubooctahedra and twinned nanoparticles. Here we describe a new procedure where Pd triangular or hexagonal nanoplates could be selectively synthesized by manipulating the reduction kinetics of the polyol process. More specifically, the reduction rate was substantially reduced through the introduction of Fe(III) species and the O2/Cl- pair, two wet etchants for Pd(0). The etching power of the O 2/Cl- pair could be further enhanced by adding an acid to lower the pH of the reaction solution. Unlike the previously reported synthesis of Ag and Au nanoplates, light was found to have no indispensable role in the formation of Pd nanoplates. Both triangular and hexagonal nanoplates of Pd exhibited surface plasmon resonance (SPR) peaks in the visible region, and their positions matched with the results of discrete dipole approximation (DDA) calculation. Thanks to their sharp corners and edges, these Pd nanoplates could serve as active substrates for surface-enhanced Raman scattering (SERS).
Transformations of β-hydroxo-substituted η3-allyl Pd complexes in neutral and weakly acidic solutions
Finashina,Kramareva,Evstigneeva,Flid,Belov
, p. 685 - 694 (2005)
The oxidation of some β-hydroxo-substituted η3-allyl Pd complexes based on the simplest 1,3-dienes is studied by the 1H and 13C NMR methods in neutral and weakly acidic methods. The composition of the reaction products is
Energetic and entropic contributions to self-assembly of binary nanocrystal superlattices: Temperature as the structure-directing factor
Bodnarchuk, Maryna I.,Kovalenko, Maksym V.,Heiss, Wolfgang,Talapin, Dmitri V.
, p. 11967 - 11977 (2010)
We studied the effect of temperature on self-assembly of monodisperse colloidal nanocrystals into single-component and binary superlattices. Temperature, which serves as a weighting factor for the internal energy (U) and entropy (S) contributions to the Helmholtz free energy F = U - TS, allows tailoring relative weights of the interparticle interactions and free-volume entropy during the formation of nanocrystal superlattices. Temperature also provides a convenient tool for directing self-assembly of nanocrystals toward desired superlattice structures. We found that temperature strongly affects the structures of binary superlattices self-assembled from the mixtures of CdSe + PbS nanocrystals and PbSe + Pd nanocrystals. In the former case, small Hamaker constants for CdSe and PbS nanocrystals led to a relatively simple phase diagram, including only high-density NaZn13-, AlB2-, and NaCl-type binary superlattices. In contrast, binary superlattices self-assembled at different temperatures from PbSe and Pd nanocrystals showed a number of low-density complex phases stabilized by strong local van der Waals interactions between Pd nanocrystals. The structural diversity of nanoparticle superlattices is shown to be a result of the cooperative effect of the entropy-driven crystallization and the interparticle interactions. Both ΔU and TΔS terms associated with the superlattice formation should be of the same order of magnitude, with |ΔU| |TΔS| for the PbSe and Pd nanocrystals.
LaPdo3: The first PdIII oxide with the perovskite structure [14]
Kim,Lemaux,Demazeau,Kim,Choy
, p. 10413 - 10414 (2001)
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Hydrogen sorption in Pd monolayers in alkaline solution
Martin,Lasia
, p. 5292 - 5299 (2009)
Hydrogen adsorption/absorption at palladium monolayers (ML) deposited on monocrystalline Au(1 1 1) electrode was studied in 0.1 M NaOH solution. H charge isotherms demonstrated that adsorption started at potentials more positive than at thicker nanometric
Electroless Deposition of Palladium at Bare and Templated Liquid/Liquid Interfaces
Dryfe, Robert A. W.,Simm, Andrew O.,Kralj, Brett
, p. 13014 - 13015 (2003)
A simple, electroless approach to metallize the liquid/liquid interface is reported. The method is illustrated with the deposition of Pd at the bare water/1,2-dichloroethane interface, and for the templated deposition of Pd within the 100 nm diameter pores of γ-alumina membranes. Copyright
Magnetic properties of transition-metal nanoclusters on a biological substrate
Herrmannsd?erfer,Bianchi,Papageorgiou,Pobell,Wosnitza,Pollmann,Merroun,Raff,Selenska-Pobell
, p. e821-e823 (2007)
We have investigated the magnetic properties of transition-metal clusters with a single grain size of about 1 nm. These metallic nanoclusters have been deposed on a biological substrate. This substrate is a purified self-assembling paracrystalline surface layer (S-layer) of the Bacillus sphaericus strain JG-A12, which exhibits square symmetry and is composed of identical protein monomers. First data of the magnetic susceptibility, taken in a SQUID magnetometer at 0a crucial role for the occurrence of superconductivity in microgranular Pt by adjusting the balance between electron-phonon interactions and competing magnetic interactions.
Synthesis and some properties of Heteronuclear platinum and palladium carbonyl clusters
Fedoseev,Gerasimova,Loginova
, p. 186 - 189 (2010)
Heteronuclear clusters of general formula [PtxPd y(CO)z] were synthesized by reaction of CO with PtCl 4 + PdCl2 solutions in 95% ethanol at room temperature and atmospheric pressure. The products isol
Self-organization of spherical, core-shell palladium aggregates by laser-induced and thermal decomposition of [Pd(PPh3)4]
Ye, Enyi,Tan, Hua,Li, Shuping,Fan, Wai Yip
, p. 1120 - 1123 (2006)
(Figure Presented) Metal in the middle: Uniform, spherical, core-shell aggregates (100 ± 20 nm; see picture) are obtained by photodecomposition of [Pd(PPh3)4] to form the metal core, followed by aggregation of smaller Pd nanocrystals
Synthesis of bimetallic PdAu nanoparticles for formic acid oxidation
Suo, Yange,Hsing, I-Ming
, p. 2174 - 2183 (2011)
In this work, a simple co-deposition strategy for the synthesis of carbon-supported Pd-Au alloy was reported. Our approach involves the co-reduction of Au and Pd ions using ethylene glycol and sodium citrate as the reducing and stabilizing reagents. Both alloy and non-alloy bimetallic Pd-Au nanoparticles are produced using a right rate-limiting strategy. For example, when ethylene glycol and sodium citrate are the limiting reagent with Au and Pd ions in excess, the synthesis environment favors preferential nucleation and growth of Au nanoparticles followed by deposition of Pd either as the shell of Au core or as separate Pd clusters. On the other hand, if the supply of metal ions (not the reducing reagents) limits the reaction, it creates a synthesis condition for Pd-Au alloy particles. The as-prepared Pd-Au alloys exhibit higher Pd-specific activities towards formic acid oxidation compared with the non-alloy counterpart or individual Pd catalyst and an easier removal of adsorbed oxygen species (e.g., Oads or OHads) was observed from the surface of Pd-Au alloy with a higher content of Au.
Fabrication of high aspect ratio ferroelectric microtubes by vacuum infiltration using macroporous silicon templates
Bharadwaja,Olszta,Trolier-McKinstry,Li,Mayer,Roozeboom
, p. 2695 - 2701 (2006)
Ordered arrays of high aspect ratio (>10:1) ferroelectric Pb(Zr 0.52Ti0.48)O3 (PZT) tube structures were fabricated by vacuum infiltration of macroporous silicon (Si) templates. Improved phase purity was achieved when PZT microtubes were pyrolyzed at 300°C and partially released from the Si template to prevent a chemical reaction between the Pb and the Si during subsequent high-temperature crystallization. The free-standing microtubes were crystallized by rapid thermal annealing at 750°C for 1-3 min. Perovskite phase formation was confirmed by X-ray diffraction and transmission electron microscopy methods. Coaxial structures comprised of metallic LaNiO3, PZT, and Pd layers were also processed to enable future electrical characterization of the ferroelectric microtubes.
Catalytically active nano-porous cobalt-palladium alloys
Avisar, Shay,Shner, Yahel,Abu-Reziq, Raed,Popov, Inna,Bino, Avi
, (2022)
The potential advantages of nano-alloys and particularly, nano-porous alloys, place them at the “spotlight” of heterogeneous catalysis. Nevertheless, controlling the precise compositions of these materials is still a synthetic challenge. Previous research introduced the fabrication of metals and alloys with a high nano-scale porosity and controllable compositions, via a hydrogen-mediated chemical reduction process of metal complex salts. We have used this procedure to obtain two magnetic nano-porous Co-Pd alloys, pure porous palladium and pure porous cobalt. Single crystal X-ray diffraction studies enabled structural determination of the two Co-Pd bi-complex salts that were used as precursors for these alloys. Powder X-ray diffraction studies determined the crystalline phases of the alloys and indicated the nanometric size of their crystallites. High-resolution scanning electron microscopy indicated that these alloys assemble as highly porous clusters of interconnected nano-crystallites. It also indicated that each alloy cluster preserves the micrometric morphologies of its salt precursor. Energy dispersive X-ray spectroscopy showed that the alloys exhibit uniform composition down to the micro-level, which preserved the Co/Pd ratio within the salts. Focused ion beam tomography enabled 3D structural representation of the alloys and metals. Geometrical analysis of the 3D reconstructed data determined 90% porosity and a specific surface area of ~100 m2/g for the alloys. In addition, the alloys showed improved catalytic activity in the semi-hydrogenation of phenylacetylene, compared to the pure metals and commercial Pd/C. Moreover, their magnetic properties enabled facile recovery at the end of the reaction. The yield for styrene in this reaction was increased using “design of experiments” (DOE), a method for optimization of reaction conditions. Furthermore, our experiments implied that a highly porous structure significantly improves the selectivity of styrene in the reaction. These results demonstrated the advantage of fabricating nano-porous alloys with uniform compositions that may exhibit special properties and serve as new and efficient catalysts.
Synthesis of Cu-Pd alloy thin films by co-electrodeposition
Allemand, Morgan,Martin, Manuel. H.,Reyter, David,Roue, Lionel,Guay, Daniel,Andrei, Carmen,Botton, Gianluigi A.
, p. 7397 - 7403 (2011)
This paper presents results on the synthesis of Cu-Pd alloy thin films on Ti substrates by co-electrodeposition of Pd and Cu from nitrate-base electrolytic baths. The deposition rates of Cu and Pd were determined by Electrochemical Quartz Crystal Microbalance as a function of the electrode potential and Cu+2 and Pd+2 concentrations. It is shown that electrodeposition of copper and palladium occurs simultaneously at -0.50 V vs. SCE and that Cu-Pd thin films over the entire composition range were obtained by changing the composition of the solution. X-ray diffraction analyses indicated that these films have a nanocrystalline single-phase face-centered cubic structure and scanning electron microscopy analyses showed that potentiostatically deposited films are rough and porous, which is appropriate for electrocatalysis applications. In an attempt to get denser deposits as required for H2 purification applications, pulsed potential co-electrodeposition was performed and the effect of the deposition conditions on the roughness of the films was assessed by double layer capacitance measurements. It was shown that smooth Cu-Pd films (with Rf value as low as 8, as opposed to more than 120 for films prepared in the potentiostatic mode) could be obtained with a proper choice on the deposition conditions.
Synthesis, characterization, and biological activity of a new palladium(II) complex with deoxyalliin
Corbi, Pedro P.,Massabni, Antonio C.,Moreira, Andreia G.,Medrano, Francisco J.,Jasiulionis, Miriam G.,Costa-Neto, Claudio M.
, p. 104 - 109 (2005)
Synthesis, characterization, and biological activity of a new water-soluble Pd(II)-deoxyalliin (S-allyl-L-cysteine) complex are described in this article. Elemental and thermal analysis for the complex are consistent with the formula [Pd(C6H10NO2S)2]. 13C NMR, 1H NMR, and IR spectroscopy show coordination of the ligand to Pd(II) through S and N atoms in a square planar geometry. Final residue of the thermal treatment was identified as a mixture of PdO and metallic Pd. Antiproliferative assays using aqueous solutions of the complex against HeLa and TM5 tumor cells showed a pronounced activity of the complex even at low concentrations. After incubation for 24 h, the complex induced cytotoxic effect over HeLa cells when used at concentrations higher than 0.40 mmol/L. At lower concentrations, the complex was nontoxic, indicating its action is probably due to cell cycle arrest, rather than cell death. In agreement with these results, the flow cytometric analysis indicated that after incubation for 24 h at low concentrations of the complex cells are arrested in G0/G1.
A palladium(II) complex with a chelating (carboxy) phosphanoalkyl ligand
?těpni?ka, Petr
, p. 426 - 430 (2004)
rac-[SP-4-2]-{2-[(dimethylamino-κN)methyl]phenyl-κC 1}{[2-(diphenylphosphanyl-κP)ferrocenyl](methoxycarbonyl) methyl-κC}palladium(II) (1) was synthesized by deprotonation of [SP-4-4]-chloro{2-[(dimethylamino-κN)methyl]phenyl-κC 1}{rac-methyl 2-(diphenylphosphanyl)ferrocenylacetate-κP} palladium(II) with t-BuOK. Complex 1 was characterized by spectral methods and its reactivity studied. The structure of 1 was determined by X-ray crystallography and discussed in relation to other complexes with phosphanoalkyl ligands derived from phosphanoacetic esters.
Surface-enhanced Raman scattering of 4-mercaptopyridine on thin films of nanoscale Pd cubes, boxes, and cages
McLellan, Joseph M.,Xiong, Yujie,Hu, Min,Xia, Younan
, p. 230 - 234 (2006)
We have synthesized a variety of Pd nanoparticles of 8-50 nm in size including solid cubes, hollow boxes, and porous cages. Using 4-mercaptopyridine (4MP) as a probe molecule, we have characterized thin films for surface-enhanced Raman scattering (SERS) activity, and have found a significant level of enhancement (with factors ranging from 170 for 8-nm cubes to 1.3 × 104 for boxes). For the cubes and boxes, we observed a trend of stronger enhancement with more red-shifted SPR bands. We evaluated the sensitivity of this approach, and also used SERS to monitor monolayer formation on these particles.
Are organotin reagents derived from bis(trimethylsilyl)picoline suitable precursors for the preparation of cyclometallated complexes?
Molter, Anja,Mohr, Fabian
, p. 134 - 138 (2009)
The organotin reagents [2-PyC(SiMe3)2SnR3] (R = Me, nBu) were prepared in good yields from the reaction between the lithium salt of 2-bis(trimethylsilyl)picoline and the corresponding trialkyltin chlorides. Reac
CRYSTALLIZATION OF METALLIC GLASS Pd80Si20.
Li,He
, p. 91 - 105 (1986)
The crystallization behavior was studied by means of in situ observation during heating in a TEM. The crystallization process can be divided into four stages: ordering of atoms in the amorphous matrix, the initial stage of crystallization in which some metastable phases appear at local regions, rapid crystallization by a eutectic reaction, and metastable phases transformation to a stable phase. The structures of these metastable phases are analysed by electron diffraction.
Palladium metal and palladium oxide particle production by spray pyrolysis
Pluym, T. C.,Lyons, S. W.,Powell, Q. H.,Gurav, A. S.,Kodas, T. T.,et al.
, p. 369 - 376 (1993)
Spray pyrolysis was used to produce dense, spherical palladium metal particles at and above 900 °C in air and 800 °C in nitrogen, well below the melting point of palladium (1554 °C). Palladium oxide particles were produced at lower temperatures. At 500 °C the PdO particles were composed of nanocrystalline grains 5 to 15 nm in diameter and had surface areas of 30.2 to 32.8 m2/g. The particles became less porous and less polycrystalline as temperature increased. At 800 °C the PdO particles were polycrystalline with grains of 20 to 50 nm and a surface area of 3.23 m2/g. The Pd particles produced at 900 °C by decomposition of the oxide were single-crystalline and fully-dense. These observations are consistent with the formation of porous but not hollow aggregates of PdO at lower temperatures, which can be densified in the gas phase to form solid particles of Pd above 900 °C.
Electrodeposited Pd-Co catalyst for direct methanol fuel cell electrodes: Preparation and characterization
Tominaka, Satoshi,Momma, Toshiyuki,Osaka, Tetsuya
, p. 4679 - 4686 (2008)
Pd-Co alloy has been recently proposed as a catalyst for the cathode of direct methanol fuel cells with both excellent oxygen reduction activity and methanol tolerance, hence electrodeposition of this alloy is an attractive approach for synthesizing porous metal electrodes with high methanol tolerance in direct methanol fuel cells. In this study, we electrodeposited two types of Pd-Co films onto Au substrates by applying different current density (-10 or -200 mA cm-2); and then characterized them in terms of morphology, composition, crystal structure, and catalytic activity. Pd-Co deposited at -10 mA cm-2 was smooth and possessed smaller particles (ca. 10 nm), while that at -200 mA cm-2 was dendritic (or rough) and possessed larger particles (ca. 50 nm). Both the Pd-Co alloys were found to be almost the same structure, i.e. a solid solution of ca. Pd7Co3 with Pd-skin, and also confirmed to possess comparable activity in oxygen reduction to Pt (potential difference at 1.0 μA cm-2 was 0.05 V). As for methanol tolerance, cell-voltage was not influenced by addition of 1 mol dm-3 methanol to the oxidant solution. Our approach provides fundamental technique for synthesizing Pd-Co porous metal electrodes by electrodeposition.
Khan, Y.,Hawig, R.
, (1989)
New formamidine ligands and their mixed ligand palladium(II) oxalate complexes: Synthesis, characterization, DFT calculations and in vitro cytotoxicity
Soliman, Ahmed A.,Alajrawy, Othman I.,Attabi, Fawzy A.,Shaaban, Mohamed R.,Linert
, p. 358 - 369 (2016)
A series of new ternary palladium(II) complexes of the type [Pd(L1-4)ox]·xH2O where L = formamidine ligands and ox = oxalate, were synthesized and characterized by elemental analyses, magnetic susceptibility, UV-Vis, infrared (IR) and mass spectroscopy and thermal analysis. The spectroscopic data indicated that the formamidine ligands act as bidentate N2 donors and the oxalate as O2 ligand. The complexes (1-4) are diamagnetic and the optimization of their structures indicated that the geometry is distorted square planer with O-Pd-O and N-Pd-N bond angles ranged 82.70-83.87° and 88.21-95.02°; respectively which is acceptable for the heteroleptic complexes. The dipole moment of the complexes (13.97-18.77 Debye) indicating that the complexes are more polarized than the ligands (1.93-4.96 Debye). The complexes are thermally stable as shown from their relatively higher overall activation energies (441-688 kJ mol-1). The ligands and the complexes are proved to have good cytotoxicity with IC50 (μM) in the range of (0.011-0.168) against MCF-7, (0.012-0.150) against HCT-116, (0.042-0.094) against PC-3 and (0.006-0.222) against HepG-2 cell lines, which open the field for further application as antitumor compounds.
Synthesis and reactivity of semibridging borylene complexes
Braunschweig, Holger,Radacki, Krzysztof,Rais, Daniela,Uttinger, Katharina
, p. 5159 - 5164 (2006)
Reaction of the terminal borylene complexes [(OC)5M=B= N(SiMe3)2] (M = Cr, W) with [M′(PCy3)] (M′ = Pd, Pt) at room temperature led to spontaneous formation of the heterodinuclear complexes [(OC)4M-(μ-CO){μ-BN(SiMe 3)2}M′(PCy3)2] (M = Cr, M′ = Pd; M = W, M′ = Pd; M = Cr, M′ = Pt) with concomitant liberation of PCy3. X-ray diffraction studies revealed that the borylene ligand adopts a semibridging position between the two different metal centers, thus establishing a new coordination mode for borylenes and providing further experimental evidence for the theoretically predicted close relationship between BR and CO. After prolonged reaction times the liberated phosphine substitutes the carbonyl group in trans-position to the borylene moiety, forming complexes of the type [(Cy3P)(OC)3M(μ-CO)-{μ- BN(SiMe3)2}M′(PCy3)] (M = Cr, M′ = Pt; M = W, M′ = Pt; M = W, M′ = Pd). Heating or photolytic activation of [(OC)4M(μ-CO){μ-BN(SiMe3) 2}Pd(PCy3)] afforded the terminal borylene complexes trans-[(Cy3P)(OC)4M=BN(SiMe3)2], which were fully characterized in the case of M = Cr. Structural data of trans-[(Cy3P)(OC)4Cr=BN(SiMe3)2] confirm the presence of an enhanced Cr-B π-back-donation imposed by the phosphine ligand in trans-position.
Synthesis and mechanistic study of palladium nanobars and nanorods
Xiong, Yujie,Cai, Honggang,Wiley, Benjamin J.,Wang, Jinguo,Kim, Moon J.,Xia, Younan
, p. 3665 - 3675 (2007)
This paper describes a simple and versatile method for growing highly anisotropic nanostructures of Pd, single-crystal nanobars bounded by {100} facets and single-crystal nanorods with their side surfaces enclosed by {100} and {110} facets. According to thermodynamic arguments, Pd atoms should nucleate and grow in a solution phase to form cuboctahedrons of spherical shape with their surfaces bounded by a mix of {111} and {100} facets. Anisotropic nanostructures can only form under kinetically controlled conditions, while the cubic symmetry is broken. In the present system, we found that one-dimensional growth could be induced and maintained through an interplay of the following processes: (i) speedy reduction of the precursor to ensure prompt addition of atoms to the seed; (ii) chemisorption of bromide on the seed to promote the formation of {100} and {110} facets; and (iii) localized oxidative etching on one specific face of the seed to initiate preferential growth on this face. Experimentally, the anisotropic growth can be achieved by varying the type and concentration of reducing agent, as well as by adjusting the reaction temperature. This methodology developed for Pd has also been extended to both Au and Pt. As expected for a kinetically controlled product, the anisotropic nanostructure evolved into the thermodynamically favored shape during an aging process.
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, p. 45 - 52 (1983)
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Biochemical Characterization and Antimicrobial Activity against Some Human or Phyto-Pathogens of New Diazonium Heterocyclic Metal Complexes
Camele, Ippolito,El-Attar, Mohamed S.,El-Desoky, Sameh I.,El-Farargy, Ahmed F.,El-Shwiniy, Walaa H.,Elshafie, Hazem S.,Sadeek, Sadeek A.
, (2022/01/31)
String of vanadium (IV), zirconium (IV), palladium (II), platinum (IV) and uranium (VI) chelates of 2-cyano-2-[(2-nitrophenyl)hydrazono]thioacetamide (Cnphta) were prepared and characterized by physicochemical, spectroscopic and thermal analyses. The form
Synthesis, Structure, DFT, and Biological Activity of Metal Complexes of Norfloxacin and Metformin Mixed Ligand
Abbass, L. M.,El-Shwiniy, W. H.,El-Telbany, M.,Sadeek, S. A.,Zordok, W. A.
, p. 1774 - 1782 (2021/11/01)
Abstract: A new series of mixed ligand metal complexes has been synthesized by the reaction of Co(II), Ni(II), Cu(II), Zr(IV), Pd(II), and Cd(II) with norfloxacin (NOR) and metformin hydrochloride (MF) in 1 : 1 : 1 molar ratio. The complexes have been characterized by FT-IR, UV-Vis, and 1H NMR spectra, TG/DTG and elemental analysis, molar conductance, and magnetic susceptibility data. According to FT-IR, NOR chelates with metal ions as a bidentate ligand via one oxygen of the carboxylate group and pyridone oxygen, and MF chelates with metal ions via two imine groups. Complexes have been identified as electrolytes. Electronic and magnetic data have indicated the octahedral structure for all complexes except square planar Pd(II) complex. Antibacterial and antifungal activities of the compounds have been tested against several species, and have indicated higher inhibition against micro-organisms for the metal complexes than the mixed ligands.
