Synthesis of palladium nanoparticles

Synthesis (TCS). The very same term was independently proporsed by Corain and associates for the size controlled synthesis of palladium nanoparticles in 2004 [68]. In a number of cases they observed that palladium nanoclusters, supported on gel-type resins of different nature and obtained with the RIMP method, exhibited a remarkable agreement between the size of the cavities of swollen supports (as assessed by means of ISEC, see Section 4) and the diameter of the metal nanoclusters (Table 4, Entries 1-3) [10,11,66,71,72,87]. 

Chen W, Cai W, Lei Y, Zhang L (2001) A sonochemical approach to the confined synthesis of palladium nanoparticles in mesoporous silica. Mater Lett 50 53-56... 

Nemamcha A, Rehspringer JL, Kharmi D (2006) Synthesis of palladium nanoparticles by sonochemical reduction of palladium(II) nitrate in aqueous solution. J Phys Chem B 110 ... 

Siamaki, A.R., et ah, Microwave-assisted synthesis of palladium nanoparticles supported on graphene A highly active and recyclable catalyst for carbon-carbon cross-coupling reactions. Journal of Catalysis, 2011. 279(1) p. 1-11. 

Nucleic acid selection methods have also been exploited for the development of novel RNA enzymes or ribozymes (58). An m-vitro-selected RNA that contains the modified nucleotide 5-(4-pyridylmethyl)-uridine (Table 1) can catalyze carbon-carbon bond formation in a Diels-Alder cycloaddition, with an 800-fold rate acceleration compared with a random RNA (49). Modified RNAs that contain the same uridine modification have also been selected to mediate metal-metal bond formation in the synthesis of palladium nanoparticles (59). Modified RNAs are likely to have many other applications as novel ribozymes that catalyze important biological reactions or can be used to create novel materials. 

In a recent communication, Ohde et al. showed the synthesis of palladium nanoparticles by hydrogen reduction of Pd ions dissolved in the water core of a CO2 microemulsion 18, 21). The Pd nanoparticles so produced are uniformly dispersed in the supercritical fluid phase and are stable over an extended period of time long enough for catalysis experiments. Reduction of a... 

Song, Y, C.S.S.R. Kumar, and J. Hormes, Synthesis of palladium nanoparticles using a continuous-flow polymeric micro reactor. Journal of Nanoscience and Nanotechnology, 2004,4 788-793. 

Arcoleo et al [220] reported synthesis of palladium nanoparticles from the micellar system AOT/n-heptane. In one of the methods (A), two microemulsions were prepared in one, the water phase was an aqueous solution of K2PdCl4 and in the other, an aqueous solution of hydrazine monohydrate N2H4.H2O. The same volumes of the two were mixed to obtain the metal particles. In another method (B), hydrazine monohydrate was directly added to a Pd(AOT)2/NaAOT/n-heptane solution. Method B produced 3-5 nm particles under specific conditions, which were stable in size as a function of time or hydrogen concentration. Arcoleo etal [422] also used NaAOT /n-heptane reverse micelles with solubilized aqueous... 

Srimani D, Sawoo S, Sarkar A (2007) Convenient synthesis of palladium nanoparticles and catalysis of Hiyama coupling reaction in water. Oig Lett 9 3639-3642... 

The synthesis of palladium nanoparticles on montmorillonite layer silicates was studied. The Pd particles were prepared in situ in the interlamellar space of montmorillonite dispersed in an aqueous medium. Macromolecules were adsorbed on the support from an aqueous solution, followed by adsorption and reduction of Pd ions. The Pd° nanoparticles appear and grow in the internal, interlamellar space as well as on the external surfaces of the lamellae. Well-crystallized kaolinite clay can be disaggregated by the intercalation of DMSO to individual lamellae, which may serve as excellent supports for metal nanoparticles. After the adsorption of palladium precursor, metal nanocrystals were reduced by hydrazine or sodium borohydride between the kaolinite lamellae, i.e., in the interfacial layer acting as a nanoreactor. The incorporation of nanoparticles between the lamellae was shown hy XRD measinements. This procedure makes possible the steric control and restriction of nanoparticle growth. The stability of nanoparticles can be further enhanced hy the addition of polymers (PVP) and surfactants (alkyl-ammonium salts) that are also adsorbed between the kaolinite lamellae. The presence of the particles was also verified and their sizes were quantified by TEM measurements. 

In the early work on the thermolysis of metal complexes for the synthesis of metal nanoparticles, the precursor carbonyl complex of transition metals, e.g., Co2(CO)8, in organic solvent functions as a metal source of nanoparticles and thermally decomposes in the presence of various polymers to afford polymer-protected metal nanoparticles under relatively mild conditions [1-3]. Particle sizes depend on the kind of polymers, ranging from 5 to >100 nm. The particle size distribution sometimes became wide. Other cobalt, iron [4], nickel [5], rhodium, iridium, rutheniuim, osmium, palladium, and platinum nanoparticles stabilized by polymers have been prepared by similar thermolysis procedures. Besides carbonyl complexes, palladium acetate, palladium acetylacetonate, and platinum acetylac-etonate were also used as a precursor complex in organic solvents like methyl-wo-butylketone [6-9]. These results proposed facile preparative method of metal nanoparticles. However, it may be considered that the size-regulated preparation of metal nanoparticles by thermolysis procedure should be conducted under the limited condition. 

Wang, Z.F., Xiao, P.F., Shen, B. and He, N.Y. (2006) Synthesis of palladium-coated magnetic nanoparticle and its application in Heck reaction. Colloids and Surfaces A Physicochemical and Engineering Aspects, 276 (1-3), 116-121. 

Liu et al. prepared palladium nanoparticles in water-dispersible poly(acrylic acid) (PAA)-lined channels of diblock copolymer microspheres [47]. The diblock microspheres (mean diameter 0.5 pm) were prepared using an oil-in-water emulsion process. The diblock used was poly(t-butylacrylate)-Wock-poly(2-cinna-moyloxyethyl) methacrylate (PtBA-b-PCEMA). Synthesis of the nanoparticles inside the PAA-lined channels of the microspheres was achieved using hydrazine for the reduction of PdCl2, and the nanoparticle formation was confirmed from TEM analysis and electron diffraction study (Fig. 9.1). The Pd-loaded microspheres catalyzed the hydrogenation of methylacrylate to methyl-propionate. The catalytic reactions were carried out in methanol as solvent under dihydro-... 

Major trends can be discerned for Pd-catalysts, aimed at increasing the stability and activity. First is the use of palladium-carbene complexes [178]. Although activities are still modest, much can be expected in this area. Second is the synthesis and use of palladium nanoparticles. For example, the giant palladium cluster, Pd561phen6o(OAc)i8o [179], was shown to catalyze the aerobic oxidation of primary allylic alcohols to the corresponding a,/funsaturated aldehydes (Fig. 4.66) [180]. 

Kalaiselvi, A., Roopan, S.M., Madhumitha, G., Ramalingam, C., Elango, G., 2015. Synthesis and characterization of palladium nanoparticles using Catharanthus roseus leaf extract and its application in the photo-catalytic degradation. Spectrochim. Acta A 135, 116-119. 

Ratheesh Kumar, V. K., S. Krishnakumar, and K. R. Gopidas. Synthesis, characterization and catalytic applications of palladium nanoparticle-cored dendrimers stabilized by metal-carbon bonds. Eur. J. Org. Chem. 2012, 2012 3447-3458. 

Palladium(II) bromide is also the palladium(II) salt of choice for the synthesis of monodisperse cobalt-palladium nanoparticles (CoPd NPs) that are active catalysts for formic acid oxidation and the methanolysis of ammonia borane7 The bromide anion is thought to play a role in the growth process of the CoPd NPs7 PdBr2(SMe2)2 is used in the synthesis of palladium-polyimide films. ... 

Hydrogenation of olefins using ligand-stabilized palladium nanoparticles in an ionic liquid. Chemical Commununication, No.l4, pp. 1654 - 1655, ISSN 1359-7345 Hyeon, T. (2003). Chemical synthesis of magnetic nanoparticles. Chemical Communication, No.8, pp. 927-934, ISSN1359-7345... 

Leff DV, Brandt L, Heath JR. Synthesis and characterization of hydrophobic organically soluble gold nanocrystals functionalized with primary amines. Langmuir. 1996 12 4723-30. Teranishi T, Miyake M. Size control of palladium nanoparticles and their crystal structures. Chem Mater. 1998 10 594-600. 

Huang, K. C. and S. H. Ehrman. 2007. Synthesis of iron nanoparticles via chemical reduction with palladium ion seeds. Langmuir 23 (3) 1419-1426. 

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