Codeposition method

A. Eftekhari, Electrochemical properties of lanthanum hexacyanoferrate particles immobilized onto electrode surface by Au-codeposition method. Electroanalysis 16, 1324 (2004). 

The metal vapor ligand codeposition method has extended the array of such sandwich complexes. A wide range of substituents can be tolerated on the arene ring unusual arene M complexes have been prepared. Elschenbroichmade the interesting compound bis(j7 -phosphabenzene)vanadium, which is less air sensitive than the ligand itself. It turned out that the phosphorus heteroatom has a much stronger influence on the electron affinity of the free arene than of the bound arene. 

Table 4 Mixed arene/ligand complexes of Cr prepared via metal vapor-ligand codeposition method...

Active In, prepared by the codeposition method, with EtI gives a mixture of Etjinl, Etinij and Ini. The best results are obtained with (CH30CH2CH2)20 (diglyme) as solvent. Reduction of InClj with potassium metal in refluxing xylene under Ar delivers highly active In (In ) metal ... 

With in-situ polymerization it is relatively easy to incorporate chemically active species into the polymer using codeposition methods (48, 49) or by incorporating the electroactive species as a counter-ion in a conducting polymer. Using the latter method, species such as IrCl " and Fq(CN) have been incorporated into polypyrrole (52). 

Despite the many experiments designed to detect neutrons, their production in the Pd/D system has been difficult to prove [3,4]. This problem is explained by the small neutron production rate of 5-50 s in active Pd/D cells reported by Pons and Reischmann in 1992 [13]. Recent studies at the US Navy SPAWAR laboratory have reported significant evidence for neutron production using CR-39 integrating detectors [14]. These experiments used codeposition methods, where both Pd and D are deposited onto a substrate from a PdCl2 + LiCl + D2O solution [12]. The Navy SPAWAR CR-39 results also gave a low neutron production rate of 2.5 cm s , and it would be difficult to measure this low neutron flux using real-time detectors (P.A. Mosier-Boss, personal communication see also Ref. [14]). 

A careful study of the electrochemical properties of a blend of polypyrrole and poly(styrene sulfonate), prepared by the electrochemical codeposition method, is also described in the literature [133]. The authors used dry acetonitrile as solvent, and obtained signifi-... 

The B—B bond can be formed from BCl, by the codeposition of Cu atoms with BCI3. This serves as a convenient synthetic method for B2CI4 formation " ... 

These methods may be used to prepare mixed metal clusters. Simultaneous codeposition of Ag and Cu vapors in Ar at 10-12 K yields a mixture including atomic Ag and Cu, dimers Ag, and Cu, together with AgCu. At 77 K, CuAg4 and Cu,Ag3 clusters occur . The amount of AgCu can be increased by photoexcitation with 305 nm Ag or Cu atomic radiation. The trimer AuAgCu is produced when a mixture of Au, Ag and Cu vapors is condensed at 77 K. 

Several methods and variations have been developed to electrodeposit compounds. Most of the work described in this article concerns the formation of nonoxide compounds such as II-VI and in Vs. Oxides are probably the largest group of electrodeposited compounds (aluminum anodization for example), but will not be discussed here. The electrodeposition of H-VI compounds has been extensively studied and is well reviewed in a number of articles [24-29], The most prominent compound electrodeposition methods include codeposition, precipitation, and various two-stage techniques. 

Bath Composition Particle Size and Crystal Phase Particle Loading (g/1) Current Density (mA/cm2) Analytical Method Codeposition Results ... 

A method described by Florence and Farrer [584] separated tin from its associated lead by distillation from an aqueous sulfuric acid medium into which the vapour from boiling 50% hydrobromic acid is passed. The distillate provides an ideal supporting electrolyte for the determination of tin (II) (produced by reduction with hydrazinium hydroxide) by anodic stripping at a rotating vitreous-carbon electrode in the presence of codeposited mercury [585,586]. The tin is deposited at -0.70 V versus the SCE for 5 minutes, and then stripped at -0.50 V during a sweep from -0.70 V to -0.45 V at 5 V per minute. Tin in seawater is coprecipitated on ferric hydroxide, and the precipitate is then dissolved in the aqueous sulfuric acid, and subjected to the above procedure. The average content for Pacific coastal waters was found to be 0.58 xg/l. 

Codeposition produces some of the better II-VI electrodeposits and, as can be seen in Table 1, has been used and studied extensively. Aqueous codeposition of CdTe serves as a good example of the method. The deposition is usually performed at an underpotential for Cd, at a potential where the Cd deposits exclusively on previously deposited Te. Te, on the other hand, is more noble than Cd and is thus deposited at an overpotential. The tellurite concentration, however, is kept far below that of the Cd+ so there is a large excess of Cd+l As soon as Te deposits, Cd quantitatively underpotentially deposits on top, providing control over deposit stoichiometry. 

The colloidal particles are often deposited on metallic electrodes in the form of adsorbed coatings. Rubber and graphite coatings can be formed in this way, using solvent mixtures (water-acetone) as the dispersion media. The advantage of this method is that additives can firmly be codeposited with, for example, rubber latex. Thermionic emitters for radio valves are produced in a similar manner. The colloidal suspensions of alkaline earth carbonates are deposited electrophoretically on the electrode and are later converted to oxides by using an ignition process. 

Fig. 1, the metal atoms may be generated in an electrically heated crucible and co-condensed with the substrate on the cold walls of the reaction vessel. To minimize gas-phase reactions, a good vacuum must be maintained in the reactor during this codeposition. An alternative procedure is to condense the metal vapor into a well-stirred solution of the reactant in a suitable solvent cooled to a temperature at which the vapor pressure of the solution is <10 3 torr. This method has special advantages for the preparation of unstable organometallic compounds and for reacting metal atoms with nonvolatile substrates.2... 

Additional spectroscopic information on the chemistry of the TMM triplet state now has been provided by the experiments of Maier et al., who have prepared TMM in substantial quantities by the irradiation of methylenecyclopropane in a xenon matrix at 10 K in the presence of codeposited halogen atoms. This experiment has permitted them to record the infrared (IR) spectmm of TMM, all the observable bands of which are in agreement with those calculated by ab initio methods. They also were able to supply direct evidence for a photochemical ring-closure reaction, TMM —> methylenecyclopropane, by irradiation of the biradical at 254 nm. The disappearance of the TMM IR absorptions is accompanied by growth of the methylenecyclopropane bands. Of course, this observation cannot be taken as a demonstration that the reaction reported by Dowd and Chow, namely, thermal cyclization of TMM, actually occurs. 

One of the modem methods is associated with the application of pyrophoric metals formed, for examle, as a result of low-temperature gas phase codeposition with toluene vapor (MVS-metal vapor synthesis) [757],... 

For synthesis of composite films with M/SC nanoparticles distributed in the volume of a dielectric matrix, method PVD is used as co-deposition of M/ SC and dielectric material vapors. A comparison of films produced by codeposition and layer-by-layer deposition PVD methods has been made on the example of BN-Fe nanocomposite films [57]. Unlike the above considered film from alternating layers of Fe and BN, which has ordered structure, co-deposited BN-Fe nanocomposite films consist of amorphous completely disorder matrix BN containing a chaotic system of immobilized Fe nanoparticles. At the same time, these particles in contrast to those of layered film have much smaller size (d — 2.3 nm) since in this case the metal atoms are inside a matrix which slowdowns the diffusion process of atoms aggregation. 

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