Platinum , trimethyl

Monomer Production. The key industrial monomer is 2,4,6-trimethyl-2,4,6-tris-(3,3,3-trifluoropropyl)cyclotrisiloxane [2374-14-3] which is produced by the hydrosilylation of 3,3,3-trifluoropropene [677-21-4] with methyldichlorosilane [75-54-7] cataly2ed by various platinum and other noble metal compounds (eq. 3). 

Reactive halogens in various series have been removed by catalytic hydrogenation with either platinum or palladium catalysts, and other nucleophiles which have been used in chloride displacements include hydroxide ion, alkoxides, hydrosulflde, hydrazine and toluene-p-sulfonylhydrazine, and trimethyl phosphite. 

These are of two main types compounds of M", which for platinum have been known since the beginning of this century and commonly involve the stable [PtMes] group and compounds of the divalent metals, which were first studied by J. Chatt and co-workers in the late 1950 s and are commonly of the type [MR2L2] (L = phosphine). In the Pt" compounds the metal is always octahedrally coordinated and this is frequently achieved in interesting ways. Thus the trimethyl halides, conveniently obtained... 

Whereas reduction of dimethyl 1,2,7-trimethyl-l T/-azepine-3,6-dicarboxylate (5) with platinum and hydrogen in cyclohexane yields the hexahydroazepine 6, hydrogenation in methanol solution results in loss of methylamine and formation of dimethyl 2,3-dimethylbenzene-1,4-dicar-boxylate (52% mp 66-67 C).239... 

While (Bu4N)2PtMe6 is only stable at room temperature under nitrogen, the trimethyls in particular are rather stable bond energies of 160— 210 kJ mol- have been estimated for Pt—Me bond energies in various platinum(IV) methyls [191]. 

Neruda, B. et al., J. Organomet. Chem., 1976, 111, 241-248 In the exothermic reaction with trimethyl phosphite to give r/.v-dimethyl-bis(trimethyl phosphito)platinum, the azide must be added to the phosphite in small portions with stirring. Addition of the phosphite to the solid azide led to a violent explosion, probably involving the transitory by-product methyl azide. 

Muller (ISO) has recently shown that the dehydrocyclization of 2,2,4,4-tetramethylpentane to 1,1,3,3-tetramethylcyclopentane occurs on thick polycrystalline platinum film catalysts with a rate that is comparable to the formation of 1,1,3-trimethylcyclopentane from 1,2,2-trimethyl-pentane. As Muller points out, reactions (10)—(12) cannot occur from 2,2,4,4-tetramethypentane, and it is clear that either these mechanisms are inadequate, or at least there must be an alternative mechanism available. Muller suggests mechanism (14) which requires two adjacent platinum sites. 

The preparation of iodo (trimethyl) platinum (IV) of empirical formula PtI(CH3)3 was first reported by Pope and Peachey.1 The substance was produced by the reaction between platinum (IV) chloride and methylmagnesium iodide. Gilman et al.2 have repeated this method of preparation to give a 45% yield and have identified some of the side products of the reaction. Various starting materials and procedures have been used by... 

Iodo (trimethyl) platinum (IV) is a yellow crystalline product which decomposes at 190 to 195°. It is soluble in most nonpolar solvents and essentially insoluble in polar media such as water and acetone. In benzene solution, the iodo derivative is tetrameric.6 X-ray investigations have shown that in chloro-(trimethyl) platinum four platinum atoms describe a tetrahedron as do the four chlorine atoms, and the two tetrahedra are interpenetrating so as to give a cubic array of platinum and chlorine atoms. Each platinum atom is bonded to three chlorine atoms and to three terminal methyl groups. Some of the trimethylplatinum derivatives of organic chelate ligands are dimeric and in these structures the platinum is again six-coordinate.7... 

Chemically, the platinum-carbon bond in iodo(trimethyl)-platinum(IV) is relatively nonreactive and is unaffected by water or oxygen. The iodine atoms may be replaced by other ions through simple metathetical reactions. 

The rearrangement and formation of 2,2-dimethylbutane—with a quaternary carbon atom—is only possible via the above mechanism. Over platinum, 2,3-dimethylbutane (75) gave more benzene over palladium, 2,2-dimethylbutane (97a) gave more benzene. This is the opposite selectivity, as reported by Muller and Gault, for ring expansion of 1,1,3-trimethyl-cyclopentane (57). This may be more evidence that at least two different types of bond shift mechanism can occur. 

C9H21N3, N,N, N"-Trimethyl-1,4,7-triazacyclo-nonane, Megtacn complexes with chromium(lll), 34 151—154 C9H23Cl2N3Pt, Platinum(ll),... 

In the related compound a-a -dipyridyl-acetylacetonato trimethyl platinum, which is monomeric, five of the coordination positions are taken up by the dipyridyl nitrogen atoms and the methyl groups. The sixth position is occupied by the central carbon atom of the acetylacetone, not by one of the oxygen atoms 242a). The oxygen atoms then remain uncoordinated, and the rest of the acetylacetone group is considerably distorted from the highly symmetrical form it normally has in complexes. This is the only... 

CkH.jP, Phosphine, dimethylphenyl-ruthenium complex 26 273 C HU, Cyclooctene platinum complex, 26 139 C,H,N, Benzene, 2-isocyano-1,3-dimethyl-iron complexes, 26 53, 57 C H N, Benzenemethanamine, N,N,2-trimethyl-... 

The alkyl cyanurates are thermally stable, although they decompose on passing over red hot platinum metal to yield cyanic acid and alkenes. (Trimethyl cyanurate is exceptional it decomposes to methyl isocyanate.)... 

Dichloro(2,3-diamino-K2 N2,N3-N,N, N-trimethyl-1 -propanaminium)platinum(II) chloride... 

Recently, Rooney and co-workers (23,58,59) have questioned the view that triadsorption by loss of 3 hydrogen atoms from the alkane is the minimum requirement for bond-shift reactions. They studied the isomerization of a series of caged hydrocarbons in excess hydrogen on palladium and platinum catalysts. The compounds were chosen in order to render difficult or totally exclude a mechanism involving aory-triadsorbed species. Thus, l,7,7-trimethyl[2,2,l]-heptane interconverts with its endo- and exo-2,3,3-trimethyl isomers, bicyclo-[3,2,2] octane changes to bicyclo[3,3,l] nonane, and protoadamantane to... 

When instead of platinum sheets as electrodes BDD material was employed the 13 14 ratio improved tremendously. Surprisingly, this direct electrochemical conversion of 12 gave the desired biphenol 13 in almost exclusive selectivity of 18 1 for 13 14. The typical pentacyclic by-product 15 could not be detected in the crude product. Inspired by the conditions for the electrosynthesis of trimethyl orthoformate (see Sect. 4.3.1 in Chap. 44) we applied to our conversion alcohols as common solvents for organic transformations at BDD electrodes. 

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