The relative stabilities of tungsten hexacarbonyl, silver neodecanoate some metal acetyl- and hexafluoroacetylacetonates and the thermal properties of the palladium(II) acetonates

Пастон, С. В.; Reisman, Arnold

doi:10.1007/bf02657788

Cited by 12 publications

(9 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…25,26 Major weight loss, accounting for about 40% of the sample mass, takes place with maximum rate at 225 C. Less pronounced weight loss occurs with maxima at 300 and 390 C. About 24% of the sample had not evaporated by 500 C, which is comparable to the 28% reported by others. 27 The weight loss observed for Co(acac) 2 at about 170-250 C was probably caused by evaporation of Co(acac) 2 , since a shoulder in the DTA curve, next to the peak caused by melting, accompanies this weight loss. At higher temperatures, the TG/DTG peaks are accompanied by endothermic DTA peaks, indicating that reorganisation or decomposition of the residual Co(acac) 2 has taken place.…”

Section: Resultsmentioning

confidence: 94%

Preparation of silica-supported cobalt catalysts through chemisorption of cobalt(ii) and cobalt(iii) acetylacetonate

Rautiainen

Lindblad

Backman

et al. 2002

Phys. Chem. Chem. Phys.

View full text Add to dashboard Cite

Silica-supported cobalt catalysts, Co/SiO 2 , were prepared by the saturating chemisorption of gaseous cobalt acetylacetonate reactants, Co(acac) 2 and Co(acac) 3 . Thermoanalytical investigation indicated that both reactants are suitable for the preparation of cobalt catalysts in the temperature range 170-220 C. Co(acac) 2 and Co(acac) 3 gave identical cobalt loading on silica. Moreover, diffuse reflectance Fourier transform infrared spectroscopy showed that the chemisorbed species formed from the two reactants were identical. The identical species are explained by the transformation of Co(acac) 3 to Co(acac) 2 before reaction with the silica. Ligand exchange reaction between the reactants and the OH groups of silica led to surface-bound Co-acac structures. In addition, the reactants adsorbed molecularly on the surfaces, at least on surfaces that contained a low number of reactive OH groups. Chemisorption of the reactants reached saturation level with an acac ligand density of about 2.8 acac per square nanometer. Calcination at 450 C removed the acac ligands of the surface complex. Through repetition of the cycles of Co(acac) 3 reaction and calcination up to five times, Co/SiO 2 catalysts were prepared with 6 to 19 wt.% Co, that is, 2 to 8 Co atoms per nm 2 .

show abstract

Section: Resultsmentioning

confidence: 94%

Preparation of silica-supported cobalt catalysts through chemisorption of cobalt(ii) and cobalt(iii) acetylacetonate

Rautiainen

Lindblad

Backman

et al. 2002

Phys. Chem. Chem. Phys.

View full text Add to dashboard Cite

show abstract

“…The other surface was a tetrasulfide-terminated self-assembled monolayer solution grown on the native oxide of Si(100) via bis [3-(triethoxysilyl)propyl] tetrasulfide (>97 %, Gelest Inc., Morrisville, PA). The details of the growth and characterization of this monolayer has been published previously [17].…”

Section: Methodsmentioning

confidence: 99%

“…Fortunately, Pd II (hfac) 2 sublimes without decomposing, as has been shown by Poston and Reisman. [17] Second, the metallorganic should not decompose at the surface of the substrate until temperatures are reached that exceed the deposition temperature of the metal. This has been shown previously with Pd II (hfac) 2 to be 230 C on Ir [9] and on an unspecified surface.…”

Section: Palladium Ald On Irmentioning

confidence: 99%

Substrate‐Independent Palladium Atomic Layer Deposition

Senkevich¹,

Tang

Rogers

et al. 2003

Chemical Vapor Deposition

View full text Add to dashboard Cite

A novel method is presented for the atomic layer deposition (ALD) of palladium on a tetrasulfide self-assembled monolayer functionalized SiO 2 surface. Additionally, a novel reducing agent (glyoxylic acid) was used to remove the organic ligands from the chemisorbed palladium(II) hexafluoroacetylacetonate metallorganic. Glyoxylic acid is an effective reducing agent above 200 C, which is not optimal for palladium but it is effective enough to show proof-of-concept and deposit a Pd ªseedº layer. Palladium was also deposited on iridium at 80 C and 130 C via a hydrogen process or on the Pd seed layer at 80 C. The 60 Pd film grown on the tetrasulfide self-assembled monolayer (SAM) showed nearly random texture and higher carbon and fluorine contamination levels compared to the one grown on Ir. The 55 film grown on Ir at 80 C is highly (111) textured with a grain size of~60 , as shown by reflection high energy electron diffraction (RHEED). The higher contamination levels of the Pd film deposited on the tetrasulfide SAM, as measured by X-ray photoelectron spectroscopy (XPS), is attributed to the high temperatures needed to deposit the Pd seed layer. The higher deposition temperatures cause more dissociation of the hfac ligand and a higher metallorganic desorption rate. These equate to less Pd being deposited and with higher contamination levels.

show abstract

“…Poston and Reisman [22] have investigated the relative stabilities of palladium acetylacetonate and palladium hexafluoroacetylacetonate using differential thermal analysis (DTA) and weight loss analysis. In general, the acetylacetonates decompose in solid state at relatively low temperatures (100°C to 200°C); several of them exhibit appreciable vapor pressures at temperatures below which their decomposition rate is significant.…”

Section: Introductionmentioning

confidence: 99%

“…Heating palladium acetylacetonate in argon at £2°C min À1 shows the onset of an endotherm at approximately 196°C, at the conclusion of which a product containing 75 pct palladium was found, with the remainder comprised of carbon, hydrogen, and oxygen. [22] These authors found that, in an oxidizing atmosphere at the same heating rate, [Pd(acac) 2 ] decomposes exothermically at 180°C, yielding essentially pure palladium. Continued heating in oxygen to 800°C results in pure PdO.…”

Section: Introductionmentioning

confidence: 99%

A Kinetic Study of the Nonisothermal Decomposition of Palladium Acetylacetonate Investigated by Thermogravimetric and X-Ray Diffraction Analysis Determination of Distributed Reactivity Model

Janković

Mentus

2009

Metall Mater Trans A

View full text Add to dashboard Cite

The nonisothermal decomposition process of the powder sample of palladium acetylacetonate [Pd(acac) 2 ] was investigated by thermogravimetric (TG) and X-ray diffraction (XRD) techniques. The experimental TG and differential thermogravimetric (DTG) curves were obtained at different heating rates (b = 2°C min À1 , 5°C min À1 , 10°C min À1 , 20°C min À1 , and 30°C min À1 ) under a pure nitrogen (N 2 ) atmosphere. The kinetic triplet (A, E a , and model function f(a)) was determined using different kinetic methods. It was found that the apparent activation energy was not really changed and was almost independent with respect to the level of conversion (a). This result suggests that the nonisothermal decomposition process of palladium acetylacetonate follows a single-step reaction. Practically constant E a values approximating 140.1 ± 1.5 kJ mol À1 were found. It was concluded that the reaction model R3, for the integral composite method I, is the model with the best regression and with kinetic parameters that are both unique and very similar to those obtained by the Friedman isoconversional method. In addition, it was found that the results obtained from both the Master-plot and Ma´lek methods confirm the results obtained from the multiple-rate isotemperature method, specifically, that the R3 (contracting volume) reaction mechanism can best describe the investigated decomposition process. By applying the Miura procedure, a distributed reactivity model (DRM) for the investigated decomposition process was established. From the a = a(E a ) dependence, the experimental distribution curve of E a was estimated. Using the nonlinear (NL) least-squares analysis, it was found that the Gaussian distribution model (with distribution parameters: E 0 = 138.4 kJ mol À1 and r = 0.71 kJ mol À1 ) represents the best reactivity model for describing the investigated process. Also, it was concluded that the E a values calculated by the Friedman isoconversional method and the estimated distribution curve (f(E a )), are correct, even in the case in which the investigated decomposition process occurs through a single-step reaction mechanism.

show abstract

The relative stabilities of tungsten hexacarbonyl, silver neodecanoate some metal acetyl- and hexafluoroacetylacetonates and the thermal properties of the palladium(II) acetonates

Cited by 12 publications

References 11 publications

Preparation of silica-supported cobalt catalysts through chemisorption of cobalt(ii) and cobalt(iii) acetylacetonate

Preparation of silica-supported cobalt catalysts through chemisorption of cobalt(ii) and cobalt(iii) acetylacetonate

Substrate‐Independent Palladium Atomic Layer Deposition

A Kinetic Study of the Nonisothermal Decomposition of Palladium Acetylacetonate Investigated by Thermogravimetric and X-Ray Diffraction Analysis Determination of Distributed Reactivity Model

Contact Info

Product

Resources

About