Platinum xanthate complexes

Reaction of methyldiphenylphosphine with the benzyl xanthate complexes [M(S2COCH2Ph)2] (M = Pd, Pt) in chloroform yields the dithiocarbonato complexes (43). The platinum complex (43 M = Pt) undergoes a variety of reactions in chloroform solution, e.g. treatment with HC1 yields m-[(Ph2MeP)2PtCl2].149... 

The crystal structure of platinum ethylxanthate, Pt(S2COEt)2,251 NMR spectroscopic studies of platinum xanthate-multidentate polyphosphine complexes,252-254 and a comparative study of the electronic spectra of Ni, Pd, and Pt xanthates255 have been reported. 

Extended Htickel calculations have been used to analyze the electronic structure of platinum complexes and also to rationalize their reactivity with various nucleophiles. Their inability to form four coordinate species of the type [Pt(S2CNR2)(ri -S2CNR2)2] has been ascribed to the lower charge on platinum (when compared with xanthate complexes), strong platinum-sulfur bonds and a repulsive interaction between the platinum 2>d electrons and the incoming ligand (1601). 

If the alternative potassium hydroxide method is employed for the separation of Groups IIA and IIB, the KOH extract may contain As, Sb, Sn, Se, Te, and part of the Mo the residue may contain, in addition to HgS, PbS, Bi2S3, CuS, CdS, and PdS, the gold and platinum partly as sulphides and possibly partly in the form of the free metals. Mo is readily identified by the potassium xanthate or a-benzoin oxime test. The Au and Pt will accompany HgS after extraction with dilute nitric acid upon dissolution in aqua regia, Pt may be identified as the dimethylglyoxime complex in the presence of m hydrochloric acid after the Pb, Bi, Cu, and Cd have been removed. 

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