Tetrachloroplatinic acid, solution

Chatt1 has prepared and investigated this complex and presented evidence to show that the butadiene acts as a bridging group between two PtCl3 units. The present preparation represents a slight modification of his procedure particularly with regard to the control of the acidity of the potassium tetrachloroplatinate(II) solution. 

Platinum dichloride dissolves in hydrochloric acid to form a dark brown complex acid, tetrachloroplatinic(ll) acid, H2PtCl4 in the solution ... 

To 45 ml. of 5 M aqueous hydrochloric acid in a 125-ml. Erlenmeyer flask is added 4.5 g. of potassium tetrachloro-platinate(II) (0.00108 mole). The flask is sealed with a rubber, serum cap and deoxygenated immediately by flushing for 30 minutes with nitrogen or ethylene through a polyethylene tube extending into the solution and attached to a needle inlet, with another needle as gas outlet. (Some undissolved potassium tetrachloroplatinate(II) may remain at this stage.) Forty milli-... 

Berzelius1 prepared platinum(II) chloride by evaporation of a solution of hexachloroplatinic(IV) acid and heating of the residue to about 300 to 350° with constant stirring. This method has been more recently modified by Kharasch and Ashford.2 Nilson3 obtained a more pure product by evaporation of a solution of tetrachloroplatinic(II) acid. The preparation of pure platinum (II) chloride from readily obtainable hexachloroplatinic(IV) acid 6-hydrate is given here. This is an adaptation of the method of Wohler and Streicher.4... 

When a Carius tube is used, potassium tetrachloroplatinate (2 g) in water (9 ml) and concentrated hydrochloric acid (1 ml) in a 150-ml Carius tube is cooled in liquid nitrogen, and ca. 1.5 ml of liquid ethylene is condensed into the tube, which is sealed. The mixture is allowed to warm to room temperature, and the tube is shaken mechanically for 36 hr. During this time, the original deep-red solution changes color to yellow. 

This base (as the trihydrochloride) reacted with hexachloroplatinic(IV) acid to form the salt, XXXIV, in which the central nitrogen atom becomes asymmetric attempts to resolve it not unexpectedly failed as this group would almost certainly have very low, optical stability. The salt, XXXIV, when treated with silver salts, lost hydrogen chloride with the formation of the salt, XXXV. With potassium tetrachloroplatinate(II), the salt, XXXVI (X = Cl), was obtained and was more readily isolated after treatment in solution with sodium bromide or iodide as the cream-colored XXXVI (X = Br) or XXXVI (X = I), respectively. The free base reacted with aquopentamminocobaltic trichloride to give the... 

A silk catalyst of especial efficiency has been developed for hydrogenation of aromatic nitro compounds.51 Boiling silk fibroin fibres with an aqueous solution of potassium tetrachloroplatinate affords a brown, hair-like silk-platinum chelate from which the actual black silk catalyst is obtained by hydrogenation at 9 atm in the presence of 1 % acetic acid. Its activity, calculated on platinum content, for hydrogenation of nitrobenzene to aniline, is 250 times that of platinum dioxide. 

II. A chocolate-brown form of platinum (II) chloride can be prepared by careful concentration of a solution of tetrachloroplatinic (II) acid (see p. 1570) in hydrochloric acid this material is more soluble in hydrochloric acid and aqueous ammonia than the product obtained by method I. 

The preparation of compounds of platinum(II) usually involves a preliminary preparation of platinmn(IV) compounds. For example, the sjmthesis of metal salts by treating a solution of tetrachloroplatinic(II) acid mth carbonates or chlorides requires the preliminary preparation of the acid by reducing hexachloroplatinic(IV) acid with a suitable reagent such as sulfm dioxide. Otherwise, a metallic hexachloroplatinate(IV) may be reduced to the corresponding tetrachloroplatinate(II) by sxilfur dioxide, potassium oxalate, potassium hydrogen sxil-fite, hydrogen sulfide, potassium hypophosphite, or copper(I) chloride. ... 

Tetrammineplatinum(II) chloride may be prepared by heating any one of the following with excess aqueous ammonia until a colorless solution results platinum(II) chloride tetrammineplatinum(II) tetrachloroplatinate(II) (Magnus s green salt), [Pt(NH3)4][PtCl4] diamminedi-chloroplatinum, [Pt(NH3)2Cl2] or a solution of tetra-chloroplatinic(II) acid. The present method involves the preparation of pure tetrammineplatinum(II) tetrachloro-platinate(II) and its subsequent reaction with aqueous ammonia. 

Carbene complex 138 has been isolated under considerably less extreme conditions/" The air and water stable complex 138 is isolated from the reaction of potassium tetrachloroplatinate with a free pyridine in ethanoic acid, even though a cyclometallated complex coordinated to the platinum through a nitrogen might have been anticipated. In principle, the carbene structure of 138 could be redrawn as the ionic structure 139 (Scheme 34) however, a short Pt-G distance of 1.952(7) A in the X-ray structure and a solution G chemical shift of 324 ppm for the carbon bonded to platinum confirms that carbene form 138 more accurately represents the molecular form present. 

Platination is smoothly brought about in aqueous solution, with potassium tetrachloroplatinate used as the platination agent and mild solution acidity maintained... 

Two examples of selective metal deposition follow. Parallel cylindrical PS-b-PMMA is treated with a palladium colloid, which selectively deposits on top of the polystyrene domains.Electroless deposition of nickel then forms on the palladium particles. Alternatively, PS-b-P4VP with cylindrical P4VP aligned parallel to the substrate is soaked in a weakly acidic aqueous solution of metal salts such as gold chloride, sodium tetrachloroplatinate, and sodium tetrachloropalla-date. ° ° A plasma etch removes the polymer film and reduces the metal patterned in the P4VP domains. 

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