Tetraphenylethane derivatives

These radical polymerizations may simply be considered as an insertion of monomer molecules into the R-R bond of the initiator leading to the polymer with two initiator fragments. Thus, the end groups of the polymer are controlled by the initiator used. Otsu proposed the name iniferter (im tiator-trans/er agent-terminator) for the initiators with such functions [64]. Many radical initiators, such as peroxides, azo compounds, tetraphenylethane derivatives, and organic sulfur compounds, may be expected to serve as an iniferter, if monomers and polymerization conditions are selected. Some peroxides show relatively high... 

Crivello et al. synthesized block copolymers consisting of poly(DMS) and vinyl polymer sequences to modify the mechanical properties and solvent resistance of poly(DMS). They used tetraphenylethane derivatives incorporated into the poly(DMS) chain through hydrosilylation (Eq. 26) [124-126] ... 

Most of the thermal iniferters containing carbon-carbon bonds are symmetrical disubstituted tetraphenylethane derivatives, such as tetraphenylsuccino-dinitrile, tetra(p-methoxy phenyl) succinodinitrile, pentaphenylethane,... 

The tetraphenylethanes described above are symmetrical compounds used to generate the same two radicals by dissociation, while pentaphenylethane (28) is an unsymmetrical derivative, giving two different radicals, triphenylmethyl and diphenylmethyl radicals [138]. The former cannot initiate radical polymerization, but the latter is available as an initiating radical to produce the polymer 28, which can function as the polymeric iniferter [106]. 

The photodecomposition of benzylamine has recently been investigated. Terenin et reported that the major decomposition products, as analyzed by kinetic mass spectroscopy, are H + PhCH2NH, with only a trace of the species NHj and PhCH2. However, irradiation of A -methylbenzylamine or A, A -dimethylbenzyl-amine in ether, yields toluene (f> = 0.085) and dibenzyl, presumably via C-N cleavage the effective radiation was about 2700 The photodecomposition of A-methyl-l,l-diphenylmethylamine and other derivatives also proceeds via C-N cleavage since the major product is diphenylmethane varying amounts of 1,1,2,2-tetraphenylethane were also detected, depending on the solvent viscosity, viz. 

The high yield of 30 is ascribed to the displacement of the benzhydryl group by the lithio derivative of 29. The tetraphenylethane, 32, is reported to result from a displacement on 28 by benzhydryllithium which may have resulted from the decomposition of the methyl ylid to an immonium ion-pair. 

An acid-base reaction has also been used to generate a derivative of 2,2,2-triphenylethylsodium with resultant rearrangement. Thus Hauser and co-workers (12) allowed 1,1,1,2-tetraphenylethane (12) to react with phenylsodium in decane-heptane at -lOO lC to give after protonation I, l, 2,2-tetraphenylethane (13). This rearrangement was reasonably interpreted to occur by the process of Scheme 2. 

The thermal decomposition of diphenyidiazomethane in aprotic (hydrocarbon) solvents gives benzophenone azine and tetraphenylethane as the principal identifiable products , while in hydroxylic solvents the appropriate derivative of benzhydrol accompanies the azine . Kinetic studies of the decomposition of diphenyidiazomethane in xylene and in 1-methylnaphthalene at about 100°C have shown that the reaction is first-order in diazo compound this has been interpreted as supporting the intermediate formation of di-phenylcarbene, viz-... 

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