Dichlorobis Diethyl Sulfide Platinum II

Submitted by George B. Kauffman and Dwaine O. Cowan Checked by F. P. Dwyeb, f J. W. Hogarth, f and A. M. SARGEsoNf 

The action of an equivalent amount of the alkyl sulfide on potassium tetrachloroplatinate(II) yields the bright yellow trans chloride, while excess sulfide gives the very weakly greenish-yellow cis chloride.112,6,7 Since separation of the two isomers is a difficult and lengthy process, experimental conditions should be chosen so that only one isomer is formed. This is done, as far as possible, in the methods given below for the diethyl sulfide compounds. 

The melting points of these isomers are very sensitive to impurities (see properties). The diethyl sulfide used in these preparations is freed of mercaptan impurities by shaking with mercury(II) oxide, followed by filtration and distillation only the fraction boiling at 92 to 93° is used. 

KsPtCU + 2(C2H5)2S (excess) m-[Pt (C2H6)2S 2Cl2] + 2KC1  

A solution of 4.15 g. (0.01 mol) of potassium tetrachloro-platinate(II) in 50 ml. of water is shaken vigorously in a 250-ml., glass-stoppered Erlenmeyer flask with 4.31 ml. (3.61 g. = 0.04 mol) of diethyl sulfide (density, 0.837) until the originally deep red supernatant liquid has become colorless (ca. 15 minutes). The mixture is allowed to remain in the stoppered flask for about 24 hours, whereupon the yellow precipitate of trans isomer initially formed above dissolves. The resulting clear yellow solution is filtered if necessary, transferred to an evaporating dish, and evaporated to dryness at room temperature, f Caution. A hood should be used. This evaporation can be accomplished in about 10 to 20 hours if a constant flow of air is maintained above the dish. 

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The chlorination procedure is the same as that for the cis isomer except that only 7.5 ml. of benzene (an excess may result in an oily product) is used to dissolve the 1.85-g. (0.0042-mol) sample of irans-dichlorobis(diethyl sulfide)-platinum(II) and the impure product is recovered quantitatively by evaporation of the benzene solution with a stream of air. The orange-yellow residue is dissolved in a minimum amount (45 to 55 ml.) of boiling ethanol, and the solution is allowed to cool first to room temperature t and then in an ice bath for 15 minutes. The fine, lemon-yellow... 

Pt(C2H4)2Cl2l Dichloro(diethyl-ene)platinum(II), 6 215 PtKCaHOaSlaCU Dichlorobis (diethyl sulfide)platinum(II), 6 211, 212, 213... 

First, a mixture of vinyl-terminated PDMS and Si02 particles (0.9 pm) was dispersed in toluene by a soniher for 2 min, then the cross-linker tetrakis(dimethy-siloxy)silane and the catalyst c 5-dichlorobis(diethyl sulfide)platinum(II) were added to the mixture. The Si02 particle concentration in the final film was about 50 wt%. Films were applied onto clean aluminum panels by an automatic film applicator and cured at 60° C for 3 h. 

The complexes of platinum(IV), less well known than those of platinum(II), can be prepared by oxidation of the latter. Such a conversion often proceeds with retention of configuration. Early workers reported that halogenation of either cis- or irans-dihalobis(dialkyl sulfide)platinum(II) resulted in only one product. The compound obtained by Loir and R y and Bose-R y by treating diethyl sulfide with aqueous or alcoholic H2[Pt(OH)2Cl4] was probably mainly the trans isomer. The preparation given here, based on the work of Angell, Drew, and Wardlaw, involves the chlorination of cis- and benzene solution. In this nonpolar solvent, isomerization is minimized. 

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