Platinate trans-, chloride

Gis-dichloro-diammino-platinum, [Pt(NH3)2Cl2], was first prepared by Peyronne.2 It is easily formed by adding ammonia to a cold solution of platinous chloride in hydrochloric acid, when a greenish-yellow voluminous precipitate separates. This is boiled with water and filtered hot, when, on cooling the filtrate, the substance crystallises in yellow microscopic needles. It is sparingly soluble in water, and is more pure yellow than the isomeric trans-compound. Both cis- and fraws-dichloro-diammino-platinum are obtained on heating tetrammino-platinous chloride with hydrochloric acid. 

The approved platinum complexes, with antineoplastic activity, differ in their photochemical stability. Among these, cisplatin, in particular, undergoes a photolysis reaction. Early studies proposed that this degradation was due to the photoaquation of the chloride ligands, and its subsequent photon-induced isomerization to trans-platin (32,33). Later studies found that the main photolysis-induced degradation product, was trichloroammineplatinate II (TCAP) (34,35). This decomposition product is limited to 1% in cisplatin for injection by the USP. 

PtClHgNgOg, Platinum(II), diamminea-quachloro-, trans-, nitrate, 22 125 PtClosoCsjNgCg, Platinate, tetracyano-, cesium chloride (1 2 0.30), 21 142 PtClo.soNgRbjCg 3H 0, Platinate, tetracyano-, rubidium chloride (1 2 0.30), trihydrate, 21 145... 

Use for resolution of cycloalkenes. W s-Cycloalkenes of intermediate size (Cg-Cjo) should be capable of existing in enantiomeric forms because of the inability of the trans double bond to rotate with respect to the remainder of the molecule. But in the absence of salt-forming groups, resolution cannot be accomplished by the usual methods of forming derivatives. However, Cope et al.s found that the strong tendency of an alkene to complex with a platinum compound provides an effective method of resolution. The complex of ethylene with platinous chloride and (+) or (-)-a-methylbenzylamine exists in only one form since ethylene is symmetrical. But addition of the base to a solution of the platinum complex of trans-cyclooctene opens the way for formation of the diastereoisomeric complexes derived from the R- and S-forms of the base. Fractional crystallization at —20° (liquid at 25°) effected separation. Liberation of the (—)-hydrocarbon from the complex with potassium cyanide gave a product of aD — 411°. 

A solution of 4.15 g. (0.01 mol) of potassium tetrachloro-platinate(II) in 50 ml. of water is shaken vigorously in a stoppered 250-ml. wide-mouth container with 4.99 ml. (4.05 g. 0.02 mol) of freshly distilled tri-n-butylphosphine (density, 0.8118 g./ml.) until no further lightening of the color of the supernatant liquid occurs (about 3 hours).f The resulting waxy salmon-colored mass, containing predominantly cis isomer but also some trans isomer, is scraped from the sides of the container, washed with several 10-ml. portions of water, and dried in a vacuum oven at 30° for about one hour. Complete removal of occluded potassium chloride and tetrachloroplatinate(II) from the isomer mixture is difficult because of its waxy nature, but is effected by subsequent purification steps. 

L = py or H2O) undergo solvolysis and oxidation to yield the mixed-valence compound [(bpy)2(0)Ru(V)0Ru(III)(py)(bpy)2r , which is an effective electrocatalyst for the oxidation of d to CI2 at pH < 4 and Cl" to OCr at pH > 11.8. Chloride ions have also been implicated as mediators in the oxidation of tetracyano-platinate(II) by gold(III) complexes and in the reversible redox reaction between trans,cis-[PtCl2(L)2(am)2] and [Pt(diars)2]. In both cases an atom-transfer redox mechanism is suggested. 

Jules Reiset (Rouen or Bapaume, 6 October, 1818-Paris, 4 February 1896) worked with Regnault on respiration (see p. 397), published an account of the Bunsen cell (see p. 287), and discovered two addition compounds of platinous chloride and ammonia called after him Reiset s first chloride [Pt(NH3) JCI2, and second chloride, the m-form of [Pt(NHs)2Cl2], and the corresponding hydroxide (Reiset s base) [Pt(NH3)2(OH)2]. The yellow trans-iorm of [Pt(NH3)2012] was discovered by M. Peyrone. ... 

For example, suppose we wish to prepare cis- and /rawr-amminedichloronitro-platinate(II). How would we proceed The procedure is outlined in Figure 5.12. If we start with the tetrachloroplatinate(II) and treat it first with ammonia and then with nitrite, the cis isomer is prepared in high purity. Note that when ammine-trichloroplatinate(II) is treated with nitrite, a chloride trans to another chloride is replaced preferentially to the chloride trans to ammine. This takes advantage of the fact that chloride is higher in the trans-directing series than is ammonia. On the other hand, when trichloronitroplatinate(II) is treated with ammonia, the chloride... 

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