Metal triphenyl compounds

Classes of metal organic compounds having potent in vitro activity include triphenyl tin esters substituted 1,10-phenanthroline 35 and 2,2 -bipyridine ° metal chelates, trans-dihalotetrapyridine rhodium salts , trialkyl stannanol and esters +2 amj triphenyl lead isocarboxy-... 

Other examples of how metal-containing compounds act through a gas phase mechanism can be mentioned. Martin and Price [116] used triphenylic derivatives of antimony, arsenic, bismuth and tributyl acetates in order to reduce the combustibility of epoxy polymers. It is known that triphenylstibine evaporates without noticeable decomposition at temperature close to 360°C. The effectiveness of its action is greater than that of the bromine flame retardant (with 46% Br). Thus when there are 7 Sb atoms per 10 000 atoms of C in the substrate (O.S nol.% of additive) the oxygen index of the material is higher than in the case c 13.7 mol.% bromine-containing flame retardant, i.e. 350 Br atoms per 10 000 C atoms in the substrate when the concentrations are equal (2. metal atoms per 1000 C atoms), the effectiveness of the compound decreases in the sequence Sb > As > Bi > Sn. Since arsenic compounds are very toxic, they are not of interest in this respect. 

Polysiloxanes (l)-(4) bearing phenyldisilanyl units could be readily prepared by copolymerization of 1,3,5-triphenyl[tris(trimethylsilyl) ]cyclotrisiloxane and cyclopolysiloxanes in the presence of a catalytic amount of an intercalation compound prepared from graphite and potassium metal in a ratio of 8 1, in high yields. 

Triphenyl- [1] and trimethylvinylsilane [2] as well as l,l-bis(trimethylsilyl)ethylene [3] are known to react with lithium metal in THF yielding 1,4-dilithiobutane derivatives by a dimerizing Schlenk addition. Interestingly, by using hexane as the solvent trimethylvinylsilane 1 does not yield the dimer product 2 but a 1 1 -mixture of the corresponding vinyllithium compound 3 and the lithioalkyne 4... 

The site of reaction on an unsaturated organometallic molecule is not restricted to the most probable position of the metallic atom or cation or to a position corresponding to any one resonance structure of the anion. This has been discussed in a previous section with reference to the special case of reaction with a proton. Although the multiple reactivity is particularly noticeable in the case of derivatives of carbonyl compounds, it is not entirely lacking even in the case of the derivatives of unsaturated hydrocarbons. Triphenylmethyl sodium reacts with triphenylsilyl chloride to give not only the substance related to hexaphenylethane but also a substance related to Chichi-babin s hydrocarbon.401 It will be recalled that both the triphenyl-carbonium ion and triphenylmethyl radical did the same sort of thing. 

Haloarenes have been found to undergo nucleopilic substitution when irradiated with the triphenyl stannyl anion46, reacting via a radical S l mechanism. In many cases the reaction will only occur under photochemical conditions. The reaction is found to proceed with chloro- and bromo-substituted arenes, but not iodo-compounds. The anion is produced either by treatment of triphenyltin chloride or hexaphenylditin with sodium metal in liquid ammonia, and will react with a wide variety of arenes (reaction 30). 

Catalytic forms of copper, mercury and silver acetylides, supported on alumina, carbon or silica and used for polymerisation of alkanes, are relatively stable [3], In contact with acetylene, silver and mercury salts will also give explosive acetylides, the mercury derivatives being complex [4], Many of the metal acetylides react violently with oxidants. Impact sensitivities of the dry copper derivatives of acetylene, buten-3-yne and l,3-hexadien-5-yne were determined as 2.4, 2.4 and 4.0 kg m, respectively. The copper derivative of a polyacetylene mixture generated by low-temperature polymerisation of acetylene detonated under 1.2 kg m impact. Sensitivities were much lower for the moist compounds [5], Explosive copper and silver derivatives give non-explosive complexes with trimethyl-, tributyl- or triphenyl-phosphine [6], Formation of silver acetylide on silver-containing solders needs higher acetylene and ammonia concentrations than for formation of copper acetylide. Acetylides are always formed on brass and copper or on silver-containing solders in an atmosphere of acetylene derived from calcium carbide (and which contains traces of phosphine). Silver acetylide is a more efficient explosion initiator than copper acetylide [7],... 

Alkali metal alkyls, particularly n-butyl lithium, are the most frequently used reagents to form metallated intermediates.246 247 In certain cases (di- and triphenyl-methane, acetylene and 1-alkynes, cyclopentadiene) alkali metals can be directly applied. Grignard reagents are used to form magnesium acetylides and cyclopenta-dienyl complexes.248 Organolithium compounds with a bulky alkoxide, most notably M-BuLi-ferf-BuOK in THF/hexane mixture, known as the Lochmann-Schlosser reagent or LICKOR superbase, are more active and versatile reagents.249-252... 

Pyridine and pyrazine can also replace up to three of the carbonyl groups in Group VI metal carbonyls to form compounds of type Cr(CO)3py3. The reaction of 4,5,6-triphenyl-l,2,3-triazine with nonacarbonyldiiron afforded 3,4,5-triphenylpyrazole in 80% yield, probably through the initial n-donor complexation of the triazine to iron carbonyl (87BCJ3062). 

Minor industrial uses include the application of silver iodide as a smoke for the seeding of clouds to induce rainfall. Compounds used for obtaining some nonflammable plastics and cellulose are benzyltriphenyl-phosphoniumiodides and [2,-(acetyloxy)ethyl] triphenyl-phosphoniumiodides (see Flame RETARDANTS, HALOGENATED FLAME retardants) (142). The addition of iodine to an aromatic hydrocarbon such as -butylbenzene results in the formation of charge-transfer complexes that display outstanding effectiveness as lubricants for hard-to-lubricate metals (143), such as titanium or steels (see also LUBRICATION AND LUBRICANTS). Iodine is also used in the production of high purity metals such as titanium, silicon, hafnium, and zirconium (144). 

It is instructive to compare a C-metal bond with e. g. a C-Cl bond. The carbon chlorine bond exists in two forms as a covalent C-Cl and as an ion pair C+, Cl-. The equilibrium between these two forms in compounds such as triphenyl methyl chloride was studied e.g. by A. G. Evans... 

Patent literature reports also on halogen-free composition for PS foams, using phosphorus compound, such as RP, triphenyl phosphate, diphenyl cresyl phosphate, APP or diphenyl phosphate, and metal hydroxide such as magnesium or aluminum hydroxide.88 It is reported that PS foams containing a mixture of EG (6-10 wt%), inorganic compound (5-10 wt%) and RP, triphenyl phosphate (TPP) or 9,10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide (DOP)), and chalk compounds (5-10 wt%)89 or containing EG and phosphorus compounds such as RP, triphenylphosphate diphenyl cresyl phosphate, APP, melamine phosphate, resorcinol diphenyl phosphate, and dimethyl methylphosphonate in suitable amounts90 fulfills DIN 4102-B2 requirements. 

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