Tetramethyl platinum

The mixture is pelletized, and 1 g of a platinum-tetramethyl-tetravinylcyclotetrasiloxane complex (2.5% Pt) is tumbled onto the pellets and then deactivated by the addition of 0.05 g of 3-methylisobutynyl alcohol. The apparently homogeneous material contains two unreacted silicones in a thermoplastic urethane matrix. 

Rundle and Sturdivant carried out the determination by x-ray diffraction of the crystal structure of the substance to which the name platinum tetramethyl and the formula Pt(CH3)4 had been assigned. They found, however, that each molecule contains four platinum atoms and sixteen methyl groups, as shown in the adjacent drawing. The molecular formula is Pt4(CH3)i6. 

Spent 2,2,6,6-tetramethyl-l-oxopiperidinium can be regenerated directly at a platinum anode in aqueous acetonitrile and aldehyde products do not undergo further oxidation to the carboxylic acid [37]. Either of the two racemic quinolyl-l-oxyls 4 functions better as catalyst for the oxidation of primaiy and secondary al-kanols, but the chiral forms do not achieve selective oxidation of one enantiomer of... 

Contrasting results are obtained for the peralkylated disilanes RMe2SiSi-Me2R (R = Me, "Bu, Bu), which yield only trace amounts of the 1,4-addition products under the same reaction conditions. Attempts to increase double silylation yields by use of other platinum or palladium catalyst precursors under carbon monoxide pressure or inert atmosphere were also unsuccessful for these peralkylated disilanes. Additionally, the reaction of tetramethyl-l,2-divinyldisilane results in conversion to an intractable product mixture, with no incorporation of the 1,3-diene. Phenyl-substituted disilanes are also effective reagents in the Pt(dba)2-catalyzed double silylation of phenylacetylene, but again, the alkylated disilanes and the vinyl-substituted disilane do not give double silylation products. 

Treatment of K[Pt(0,O-MeCOCHCOMe)(C-MeCOCHCOMe)X] with mineral acids affords a material, formulated as Pt(0, -MeCOCHCOMe)Cl(MeCOCH2COMe) in which neutral, enolic acetylacetone is rc-bonded to platinum via the C=C bond. On standing, solutions of this material in chloroform yield red [Pt( -Cl)(MeCOCHCOMe)] . Similar acidification of K[Pt(MeCOCHC-OMe)3] with HX (X = Cl, Br) yields Pt(l,3,5,7-tetramethyl-2,6,9-oxabicyclo[3.3.1]nona-3,7-diene)2X2,248 whereas sulfuric, phosphoric or nitric acid leads to polymeric [Pt(MeCOCHCOMe)2]. This compound, which is isomeric with the familiar Pt(0,O-MeC0CHCOMe)2, may aggregate by means of tridentate C,0,0-MeCOCHCOMe bridging ligands.244... 

The electrochemistry of cytochrome c is attracting much attention,690 in particular the development of electrodes for cytochrome c, which either have a redox mediator bound to the surface, or utilize a solution mediator. Examples are a platinum gauze electrode functionalized with 2,3,4,5-tetramethyl-l-(dichlorosilyl)methyl[2]ferrocenophane,691 and 4,4 -bipyridyl, which serves as a bridge between cytochrome c and the electrode.692... 

The tetramethyl Pt2n complexes, on the other hand, are prepared by reaction of [Pt2(CH3)4(SEt2)2] with a salt (Ag1, Hgn, or Tl111) of the required ligand. The latter reaction involves not only ligand coordination to platinum, but also oxidation of Ptn to Ptm and reduction of Ag1, Hgn, or Tlm [26] [96] [97]. 

Not very much had so far been reported on the 1,3-disilacyclopentanes. Small amounts of 1.1.3.3-tetramethyl-l,3-disilacyclopentane were found in the products of the pyrolysis of tetramethylsilane33) and trimethylsilane42. Furthermore, 1,1,3,3-tetramethyl (or tetraphenyl-)-2-methyl-1,3-disilacyclopentane is obtained in low yields by the reaction of HR2SiCH = CH2 (R = CH3 and CgHs) at platinum contacts43. According to the results of the synthesis of the 1,3-disila-pentanes 86 and 87 two cyclization reactions are expected to be suitable for the synthesis of 1,1,3,3-tetramethyl-1,3-disilacyclopentane a and b... 

Weyenberg and Nelson (7) reported that the strained silacycles, 1,1-di-methyl-1-silacyclobutane (1) and l,l,3,3-tetramethyl-l,3-disilacyclobu-tane (2) undergo ring opening polymerization in the presence of platinum on carbon or chloroplatinic acid [Eqs. (11) and (12)]. 

Fernandez and Zon [181], when studying the heterogeneous electron exchange between N,7V,N, 7V -tetramethyl-/ -phenylendiamine and its mono-cation radical in 12 aprotic and hydrogen-bonded solvents, using a platinum electrode, have found that Eq. (40) is approximately fulfilled with a = 0.53. 

These compounds are of quite unusual interest because their empirical formulae suggest coordination numbers 4, 5, and 7 for Pt. Platinum forms a number of compounds Pt(CH3)3X, in which X is Cl, I, OH, or SH, which exist as tetrameric molecules (Fig. 27.13(a)) in which Pt and X atoms occupy alternate vertices of a (distorted) cube. These compounds are notable for the facts that the hydroxide was formerly described as the tetramethyl compound and the iodide as Pt2(CH3)6. In the early study of [Pt(CH3)3Cl]4 Pt-Cl was found to be 2-48 the value, 2-58 A determined in [Pt(C2Hs)3Cl] should be more reliable. The following figures for the hydroxide show that there is some distortion from the highest possible cubic symmetry ... 

Previously, it had been shown that pyrolysis of (86) at 620°C in a vertical nitrogen-flow system gave a complex mixture of products, including (88) (3.5%), (64 R, R = H) (0.8%), 1,1,3,3-tetramethyl-1,3-disila-2-methylidenecyclopentane (2.1 %) and 3,3,4,5,5-pentamethyl-3,5-disilacyclo-pentene (2%) <79JOM(168)23>. Formation of disilacyclopentanes by platinum-catalyzed rearrangement of vinyl disilanes also has been reported <86JAP61207389). 

Dipotassium platinum tetrachloride, K2PtCI, (1, 350, before Dipotassium tetramethyl osmate]. Supplier Alfa Inorganics. 

---