Platinizing procedures

After the electrodes have been prepared, they should be placed in a suitable holder which is filled with distilled water or physiological saline solution. The electrodes are then connected to form a short circuit. The electrodes should remain this way for several days until the charge produced by the platinizing procedure has decayed. Figure 2.12 illustrates the decay of the dc polarization potential (as a result of the platinizing procedure) with time. 

Platinum is used therapeutically as ds-platin, carboplatin and iproplatin against tumors (Konig and Schuster 1994). Determination of Pt in serum must be carried out after enrichment procedures followed by GF-AAS. 

Balthis and Bailar6 obtained tris (ethylenediamine) chromium-(III) complexes by the oxidation of chromium(II) solutions, using a procedure somewhat similar to that used for the synthesis of cobalt (III) com plexes. Mori7 described the preparation of hexaamminechromium(III) salts from the oxidation of chromium (II) salts in the presence of ammonia. The results obtained in both syntheses have been erratic.8,9 Berman noted that the foregoing syntheses are rendered dependable by the use of a catalyst of activated platinum on asbestos. Schaeffer,100 in a subsequent study, independently used colloidal platinum as a catalyst but reported some difficulty in separating it from the product.106 The procedures recommended and described here are based on the use of platinized asbestos as the catalyst. 

The metallic character of the cation-deficient partially oxidized tetracyano-platinate complexes is of considerable interest because of their unusual anisotropic electrical properties. The method used in the preparation of these compounds is a modification of the procedure used by Levy1 and gives a higher yield of pure product than the syntheses previously described in the literature2 5 (only the potassium compound has been reported to date). 

The following procedures describe the direct preparations of fttzns-[PtCl2 P(C6H5)3 2] and trans-[PtClj [P(n-C4H9)3] 2] by the reaction between the appropriate tertiary phosphine and potassium trichlorofethylene)-platinate(II) ... 

A solution of 20.8 g. (55 mmoles) of potassium tetrachloro-platinate(II) in 100 ml. of water is prepared in a 250-ml. suction flask with a nitrogen flow through the sidearm to provide an inert atmosphere. (The procedures work equally well at halfscale.) Triethylphosphine (15 ml., 100 mmoles) is added all at once and the mixture is stirred with a magnetic stirrer at room temperature for one hour. A pink-tan precipitate of tetrakis-(triethylphosphine)platinum(II)tetrachloroplatinate(II) forms. The mixture is heated on a steam bath for one hour. The pink salt dissolves, and a layer of pale yellow dichloro-bis(triethyl-phosphine)platinum forms on the liquid. The solid is filtered, washed with water, crushed in a mortar, and dried under... 

Various procedures for platinization exist, but normally involve the deposition of platinum black from a solution of 3 per cent chloroplatinic acid (H2PtCl6) containing a small quantity of lead acetate (0.005 per cent)... 

Platinized T-4 Raney Ni.55 To a suspension of 2 g of 40% Ni-Al alloy powder in 10 ml of water is added, with vigorous stirring in a water bath of 50°C, 0.05 g of chloroplatinic acid, H2PtCl6 6H20, dissolved in 2 ml of water made alkaline with 0.4 ml of 20% aqueous sodium hydroxide. The procedure hereafter is exactly the same as... 

The catalyst was prepared from 2 g of 40% Ni-Al alloy by the procedure for the T-4 catalyst each time before use. T-4 unpromoted catalyst T-4/Pt the catalyst platinized during leaching process with 0.05 g of chloroplatinic acid (0.0185 g Pt) T-4/Pt (Delepine-Horeau) T-4 Raney Ni platinized with 0.05 g of chloroplatinic acid by the method of Delepine and Horeau (Ref. 66). 

Solubility plays an important role in the preparation of this class of materials. The bis(oxalato)platinates are less soluble than the tetracyanoplatinates, and special procedures must be developed for crystal growth. 

Proceed to either Procedure 6.1.b (trans-platin) or 6.1.c (m-platin)—the reaction solution may be divided into half and each half used in 6.1.b and c. 

Procedure 6.2 DMSO Substitution Kinetics of cis- and frans-Platin Temperature Dependence Study11... 

Procedure 6.4 Molecular Mechanics Calculations on the C/s-platin-Oligonucleotide Interactions20... 

Your DNA-ds-platin molecule is complete Run geometry optimization on this molecule using the same procedure used in steps 12-14. This calculation should not take as long as the first because you are starting with a molecule already mostly optimized. Record the final optimized energy and save your new molecule. 

A mechanically polished tin disk immersed in 0.5 M citric acid was prepared following the procedure described in the literature [59]. Because high-scan-rate voltammetric curves were recorded, a calomel reference electrode is not recommended because of its slow response [60], The reversible hydrogen electrode (RHE) was used as the reference electrode at 25°C. The required materials and reagents are a three-compartment electrochemical cell with a platinized platinum auxiliary electrode and a 0.5 M (pH = 1.8) citric acid solution prepared with triple-distilled water. 

The methods previously reported for the preparation of tetrachloroplatinic(II) acid1 and platinum(II) chloride are laborious and difficult to control. Platinum(II) chloride has been prepared by the thermal decomposition of ammonium hexachloroplatinate(IV)2 or of anhydrous platinum-(IV) chloride.3 According to a recent report,4 hydrazine sulfate is an effective reducing agent for the preparation of tetrachloroplatinate(II) salts from the corresponding hexachloroplatinate(IV) salts. This procedure has been extended to the preparation of aqueous tetrachloro-platinic(II) acid and solid platinum (II) chloride. 

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