Triphenylphosphine with platinum

Oriho-vinylbenzenethiol forms similar polymeric and hexameric complexes (55) which can be converted to monomers by reaction with two moles of triphenylphosphine per platinum. Attempts were made to remove one phosphine to give a chelate, using anhydrous silver perchlorate the product isolated had the unusual structure shown in Fig. 41. 

In studies of the reactions of organotin compounds with platinum(O) and platinum(II) complexes, we have obtained a series of cis-bis(triphenylphosphine)platinum(II) complexes in which one... 

Atom Transfer Reactions. The apparent catalysis of the auto-oxidation of triphenylphos-phine by (Ph3P)2Pt02 aroused considerable interest as a possible model for enzymatic mono-oxygenase reactions. This reaction was recently reinvestigated by Halpem and Sen who showed that intramolecular oxygen transfer does not occur. The reaction takes place via coordination of free phosphine to the platinum followed by loss of H2O2 or HO2 which can react with free phosphine. The Pt(II) species can be reduced to Pt(0) and may react with molecular oxygen. The reaction of triphenylphosphine with dioxo-... 

Ni(CH2=CH-CN)2(PPh3) and Ni(CH2=CH.CN)2(PPh3)2 were ob-tained from bisacrylonitrilenickel and triphenylphosphine 166). Platinum compounds have been obtained by reducing c2s-PtCl2(PR3)2 with hydrazine in the presence of an olefin 50). The olefins were stilbene derivatives. The compounds obtained were stable to oxidation. 

Some alkyne compounds have been isolated with platinum and nickel. The first were obtained from m-PtCl2(PR3)2 with hydrazine in the presence of the alkyne 8) or from bis(triphenylphosphine)-platinum(0) and the alkyne 184). They correspond to Pt(PR3) 2 (alkyne) and, like the corresponding nickel derivatives, can be considered tricovalent platinum (0) derivatives or square planar platinum(II) derivatives. 

Reduetive alkylation of heteroaromatic rings is possible using catalytic hydrogenation. 34 Cyclization of the substituted pyridine 442 was induced by treatment with triphenylphosphine bromine, and generated pyridinium salt 443. Isolation of 443 by Sonnet was followed by hydrogenation with platinum, generating the trail pheromone of the Pharaoh ant (3-butyl-5-methyloctahydroindolizine, 444). 35... 

For the mechanism of the triphenylphosphine-modified platinum-tin-catalyzed olefin hydroformylation, a tentative catalytic cycle was proposed (Scheme 6), in which the active catalytic species, HPtlSnClaXCOXPPha), reacts with an olefin to give the corresponding alkyl-complex. 

Both academia and industries made important contributions to the new field in the early sixties with the appearance of the first phosphine modified and other hydrogenation catalysts. An early example of a phosphine-free ruthenium catalyst was published by Halpem [6]. In 1963 Cramer (Du Pont) reported a triphenylphosphine-modified platinum-tin catalyst for the hydrogenation of alkenes [7], In the same year Breslow (Hercules) included a few phosphine complexes of late transition metals in a hydrogenation study employing metal salts reduced by aluminum alkyls, but interestingly the systems containing phosphine were less active [8] ... 

J. C. Bailar, Jr., and Hiroshi Itatani, Homogeneous Catalysis in the Reactions of Olefinic Substances. VI. Selective Hydrogenation of Methyl Linoleate and Isomerization of Methyl Oleate by Homogeneous Catalysis with Platinum Complexes Containing Triphenylphosphine, Arsine or Stibine, J. Am. Chem. Soc. 89 1592 (1967). 

A soln. of allyldiethylammonium tetraphenylboron salt in methylene chloride added to bis(triphenylphosphine)(ethylene)platinum in the same solvent, and allowed to stand 5 min. at room temp. -> diethylamine. Y ca. 100%. F. e. s. H. Kurosawa, J. Organometal. Chem. 112, 369 (1976) deallylation of acylamines with palladous acetate-cupric acetate-NaCl and related reagents s. M. Mori and Y. Ban, Chem. Pharm. Bull. 24, 1992 (1976). 

Platinum, ethylenebis(triphenylphosphine)-reactions with 5,6-dimethyl-2,l,3-benzothiadiazole, 2. 

Acyl chlorides containing an a hydrogen are smoothly converted to alkenes, with loss of HCI and CO, on heating with chlorotris(triphenylphosphine)rhodium, with metallic platinum, or with certain other catalysts. The mechanism probably involves conversion of RCH2CH2COCI to RCH2CH2—RhCO(Ph3P)2Cl2 followed by a concerted syn elimination of Rh and H. See also 14-39 and 19-12. 

Non-ionic thiourea derivatives have been used as ligands for metal complexes [63,64] as well as anionic thioureas and, in both cases, coordination in metal clusters has also been described [65,66]. Examples of mononuclear complexes of simple alkyl- or aryl-substituted thiourea monoanions, containing N,S-chelating ligands (Scheme 11), have been reported for rhodium(III) [67,68], iridium and many other transition metals, such as chromium(III), technetium(III), rhenium(V), aluminium, ruthenium, osmium, platinum [69] and palladium [70]. Many complexes with N,S-chelating monothioureas were prepared with two triphenylphosphines as substituents. 

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