Platinum complexes hydrogenation

Salts of neodecanoic acid have been used in the preparation of supported catalysts, such as silver neodecanoate for the preparation of ethylene oxide catalysts (119), and the nickel soap in the preparation of a hydrogenation catalyst (120). Metal neodecanoates, such as magnesium, lead, calcium, and zinc, are used to improve the adherence of plasticized poly(vinyl butyral) sheet to safety glass in car windshields (121). Platinum complexes using neodecanoic acid have been studied for antitumor activity (122). Neodecanoic acid and its esters are used in cosmetics as emoUients, emulsifiers, and solubilizers (77,123,124). Zinc or copper salts of neoacids are used as preservatives for wood (125). 

The only prominent antitumor tetravalent platinum complex so far is iproplatin (102). In vitro it has been shown to cause interstrand DNA-breaking and cross linking. Free radical scavengers inhibit these effects. The complex is less neurotoxic and less nephrotoxic than cisplatin. Its synthesis begins with hydrogen peroxide oxidation of cis-dichlorobis(isopropvlamine) platinum (100) to the dimethylacetamide complex 101. The latter is heated in vacuum to liberate iproplatin [25]. 

Styrene, a-ethyl-asymmetric hydroformylation catalysts, platinum complexes, 6, 266 asymmetric hydrogenation catalysts, rhodium complexes, 6, 250 Styrene, a-methyl-asymmetric carbonylation catalysis by palladium complexes, 6, 293 carbonylation... 

Eq. (77)] 114). The reaction of (Me3Si)2Pt(diphos) with hydrogen in benzene at atmospheric pressure affords Me3SiPtH(diphos) at 40° C and (diphos)jPt4 at 80° C (77). Kinetic studies showed that the reaction is first order in hydrogen and in the platinum complex (Aj = 6.0 x 10 ... 

Figure 4. Side and top views of the energetically most favorable complexes formed between protonated cinchonidine and methyl pyruvate which would yield (R)-methyl lactate (left) and (S)-methyl lactate (right), respectively, upon hydrogenation. The complexes have been accomodated on a space filling model of platinum (111) surface in order to illustrate the space requirements of the adsorbed complexes. For the sake of clarity, in the side views the carbon atoms of the reactant are marked with a white square and the oxygen atoms with an o. Data taken from ref. [41].

Hydrogen bonding between an SiOH group and fluorine occurs in the platinum complex 44 [prepared by hydrolysis of a bis(alkylidene)-silacyclopropane] in which the SbF6 anion hydrogen bonds to the platinum-containing cation (O - F distance 2.77(2) A) (249). The platinum complex 45 is not reported (250) to form hydrogen bonds, and a more recent study (210) has confirmed that there do not appear to be any OH OH or OH tt interactions. 

D. Cole-Hamilton, Liverpool University Professor Gray, some of the platinum complexes that you have prepared at the same time as producing hydrogen contain, formally at least, Pt(III). Can these compounds act as oxidising agents, either thermally or photochemically ... 

If alkyl groups having (3-hydrogens are present on platinum cis to an open site, (3-H-elimination will indeed occur, reversibly sometimes, and it can occur both from Pt(II) and Pt(IV) (52,97,213-219). Catalytic dehydrogenation of an alkane using a soluble platinum complex has been reported in an early study on acceptorless thermal dehydrogenation. At 151 °C, cyclooctane was catalytically dehydrogenated (up to 10 turnovers)... 

In the absence of triphenylphosphine a tris-SPO platinum complex forms when SPO is reacted with Pt(cod)2, which is insoluble and for which the structure is not known it could be either a hydride (4) or an oligomeric or a dimeric S PO complex (5) lacking one molecule of hydrogen. The reaction with alkene, CO and H2 gives complex 6, which was identified as the acyl tris-SPO complex by NMR. It shows an... 

Although homogeneously catalyzed reactions of platinum complexes are mostly concerned with hydrogenation, hydroformylation, isomerization and hydrosilylation reactions, the complexes trans-PtHX(PPh3)2 (X = C1, Br, I) have been used used as catalysts for the oxidative chlorination of n-pentane. H2PtCl6 and K2PtCl are used as oxidants.201... 

An interesting variation of the dehydrogenative silylation system involves the platinum complex-catalyzed reaction of 1-alkenes with disilanes to produce vinylsilanes.40 In this system, one H atom and a silyl group are released by the reactants to yield the alkenylsilane product, rather than the two hydrogens released in reactions of hydrosilanes [Eq. (6)]. 

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