Tris ethylenediamine platinum IV Chloride

Tris(ethylenediamine)platinuni(IV) chloride was first reported by A, Werner in 1917. Several variations of his method have been used, but basically the preparation from platinum involves three steps (1) the preparation of the hexachloropIatinic(IV) acid, (2) the preparation of the crude tris(ethylenediamine)pIatinum(IV) chloride, and (3) purification. The following procedure is a modification of Werner s method. 

Preparation of Hexachloroplatinic(IV) Acid. Three and eight-tenths grams (0.02 mol) of platinum metal is dissolved in 80 ml. of hot aqua regia (three volumes of concentrated hydrochloric acid to one volume of concentrated nitric acid). Nitric acid is removed from the reaction mixture by five successive evaporations with concentrated (12 N) hydrochloric acid. The solution should be evaporated almost to dryness each time. An electric hot plate is best for this process inasmuch as overheating causes the 

Preparation of Crude Tris(ethylenedianiine)platinum(IV) Chloride. Ten and one-tenths grams (0.019 mol, assuming the 6-hydrate) of hexachloroplatinic(IV) acid is dissolved in 80 ml. of absolute ethanol. After cooling this solution in an ice bath, 6.6 ml. of 98% ethylenediamine [5 mols of ethyl-enediamine per mol of hexachloroplatinic(IV) acid] is slowly added with constant stirring. A pale yellow precipitate forms immediately. The mixture is heated to 65 and is maintained at 65 + 1° in a water bath for 2 hours. Care must be exercised not to heat the reaction mixture above 70° inasmuch as a brown gum occasionally forms at higher temperatures. The mixture is stirred constantly during the digestion period. Absolute ethanol is added as required to keep the volume of the reaction mixture constant. The mixture is allowed to cool to room temperature, and the tris(ethylenediamine)platinum(IV) chloride is separated from the ethanol solution by suction filtration. The crude yellow product is washed twice with absolute ethanol. The yield of the crude wet product is about 17 g. 

Tris(ethylenediamine)platinum(IV) chloride is a white crystalline solid which is readily soluble in water and stable toward decomposition in both acidic and basic solution. Resolution of the complex cation into its optical isomers has been achieved by fractional precipitation of Z-[Pt(en)j]-Cl2(d-C4H406) on addition of ammonium d-tartrate to the racemic mixture. Racemization of the cation occurs only under extreme conditions and is accompanied by little exchange of bound ethylenediamine. A solution of the complex is quantitatively reduced to platinum metal by magnesium and hydrochloric acid. The solid complex is quantitatively reduced to platinum metal upon ignition. 

Inorganic Syntheses, Volume VIII Edited by Henry F. Holtzclaw, Jr. 1966 by McGraw-Hill Book Company, Inc. 

Submitted by D. C. Giedt and C. J. NymaiN Checked by John YouNot and R. Kent MuRMANNf 

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Bis(4-imino-2-pentanonato)nickel(II), synthesis 60 Tris(ethylenediamine)platinum(IV) chloride, synthesis 62 cis-Dichloro(ethylenediamine)platinum(Il), synthesis 63 cis- and Tetrachlorobis(diethyl sulfide)platinum(IV), synthesis 64... 

Penta-amminecarbonatocobalt(lll) chloride Potassium hexanitrocobaltate(lll) Tetra-aquadichlorochromium(lll) chloride Tris(ethylenediamine)platinum(IV) bromide Potassium tetrachlorocuprate(ll)... 

Solution, (a) potassium hexacyanoferrate(ll), (b) pentaamminechlorocobalt(lll) chloride, (c) tris(acetylacetato)iron(lll), (d) dichlorobis(ethylenediamine) -platinum(IV) chloride, (e) sodium amminebromochloronitrito-platinate(ll),... 

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