Tetraphenylethylene

A mixture of 50 g. (3.0 moles) of diphenylmethane and 82 g. (3.5 moles) of diphenyldichloromethane (p. 135) is heated under a reflux condenser until the evolution of hydrogen chloride is no longer observed. This operation requires about 8 hours. The hot mixture is poured into an open dish, allowed to cool, and washed with ether until there is no more color in the product. The resulting tetra-phenylethylene melts at 220-222° without further purification and is obtained in 88% yield. 

---

Tetraphenylethylene Glycol. This prcp iration illustnites the mild conditions under which aryl ketones may undergo bimolecular reduction to com-... 

That for tetraphenylethylene, with 16, 96, 196, and 144 structures, respectively, of these four kinds, is... 

H. Finkelstein, Ber. Dtsch. Chem. Ges. 43, 1533 (1910) J. F. Norris, R. Thomas and B. M. Brown, ibid. 43, 2940 (1910). See also J. Schmidlin and R. v. Escher, ibid. 43, 1153 (1910). The resultant dichlortetraphenyl-ethane decomposes easily, mainly with the liberation of HC1 and the formation of tetraphenylethylene with Cl substituted in the para position in one of the phenyl groups. 

In view of these results the experiments using styrene were repeated at lower temperatures and the study extended to the more nucleophilic analogs, a-methyl styrene, tetraphenylethylene. No significant shifts of benzyl proton peaks were observed in any of these cases, even with a 500-Hz scale expansion. 

Reactions of 2 with alkyl halides were generally more successful for C-C bond formation. For example, bibenzyl was formed in good yield from the reaction of 2 with benzyl bromide. Dichlorodiphenylmethane and 1 reacted to give tetraphenylethylene in 63% yield. Similarly, diiodomethane reacted with 1 to give ethylene. This area of study is continuing. 

The reaction of active uranium (U ) and benzophenone gives tetraphenylethylene (TPE) and 1,1,2,2-tetraphenylethane (TPA). 

The q1-coordinated carbene complexes 421 (R = Ph)411 and 422412) are rather stable thermally. As metal-free product of thermal decomposition [421 (R = Ph) 110 °C, 422 PPh3, 105 °C], one finds the formal carbene dimer, tetraphenylethylene, in both cases. Carbene transfer from 422 onto 1,1-diphenylethylene does not occur, however. Among all isolated carbene complexes, 422 may be considered the only connecting link between stoichiometric diazoalkane reactions and catalytic decomposition [except for the somewhat different results with rhodium(III) porphyrins, see above] 422 is obtained from diazodiphenylmethane and [Rh(CO)2Cl]2, which is also known to be an efficient catalyst for cyclopropanation and S-ylide formation with diazoesters 66). 

Other selected examples include tris(tetramethylethylene diamine-sodium)-9,9-dianthryl 143,154 alkali metal salts of 9,10-bis(diisopropylsilyl)anthracene 144,155 as well as the closely related naked 9,10-bis(trimethylsilyl)anthra-cene radical anion 145.156 This chemistry is further extended to the solvent-shared and solvent-separated alkali metal salts of perylene radical anions and dianions 146, 147,156 while other examples focus on alkali metal salts of 1,2-diphenylbenzene and tetraphenylethylene derivatives, where reduction with potassium in diglyme afforded contact molecules with extensive 7r-bonding, [l,2-Ph2C6H4K(diglyme)] 148.157 Extensive 7r-coordination is also observed in (1,1,4,4 tetraphenylbutadiene-2,3-diyl)tetracesiumbis(diglyme)bis(methoxyethanolate) 149.158... 

Although organic anion radicals are oxygen sensitive, they have been isolated as crystalline salts from a variety of electron acceptors (e.g., chloranil, tetracyanoethylene, tetracyanoquinodimethane, perylene, naphthalene, anthracene, tetraphenylethylene, etc.) and their structures have been established by X-ray crystallography.180... 

Spectroscopic Studies on Carbonium Ions derived from Aromatic Olefins. Part II. Acenaphthylene, N-Vinylcarbazole, and Tetraphenylethylene, A. Gandini and P.H. Plesch, Journal of the Chemical Society, (B), 1966, 7-10. 

Diphenylcarbene also undergoes a ring expansion of the above kind. When it was generated in the gas phase at 350°C/3Torr, small quantities of tetraphenylethylene, the triphenylheptafulvene 563 and the diphenylheptafulvalene 564 were formed in addition to fluorene (565), which was obtained in 29% yield. As illustrated in... 

In regard to the rate at which the above-mentioned addition reactions proceed, the olefines exhibit very great differences, depending on the nature of the molecule. When a double bond is shown in a formula it does not necessarily, follow that it is also capable of all the above transformations. Thus, for example, it is quite impossible to add bromine to tetraphenylethylene (C6HS)2C C(C6H5)2. The affinity of the double bond, therefore, differs from case to case. 

A further interesting point concerns unusually small differences between the reduction potentials of mono- and dianions of some molecules containing olefinic double bonds. Although in tr ns-stilbene the formation of the dianion occurs approximately 500 mV negatively to the radical anion formation [35, 120], for tetraphenylethylene the standard potentials for the R/R couple and the... 

Leigh and Arnold (1981) investigated cis-trans isomerizations about C—C bonds in substituted tetraphenylethylenes [42]. This isomerization involves a biradical or biradical-like transition structure which is attained by a 90° rotation about the double bond. The predominant action of the substituent is assumed to become evident mainly at the orthogonal stage of... 

BUTYL-HEXADECYL-SULFIDE DECYL-SULFIDE ETHYL-OCTADECYL-SULFIDE HEPTADECYL-PROPYL-SULFIDE HETHYL-NONADECYL-SULFIDE 1-EICOSANETHIOL DECYL-DISULFIDE TRI-o-CRESYL PHOSPHATE 1-PHENYLPENTADECANE 1-CYCLOPENTYLHEXADECANE 1-CYCLOHEXYLPENTADECANE 1-PHENYLHEXADECANE 1-CYCLOHEXYLHEXADECANE n-BUTYL STEARATE DIISOOCTYL PHTHALATE DIOCTYL PHTHALATE DINONYLPHENOL TETRAPHENYLETHYLENE DIISODECYL PHTHALATE... 

Anodic oxidation of tetraphenylethylene at a platinum electrode leads to the product of cycliza-tion, namely, 9,10-diphenylphenanthrene (Stuart and Ohnesorge 1971). 

The intramolecular coupling reaction does not occur when diphenylethylenes, that is, stilbene and its methyl derivatives, are electrolyzed under the same conditions (Stuart and Ohnesorge 1971). This difference in the anodic behavior of these substances was attributed to the low stability of the cation-radicals of stilbene and its methyl derivatives in comparison to the cation-radicals of tetraphenylethylene. The participation of the cation-radicals in the cyclization of tetraphenylethylene has been unequivocally proved (Svanholm et al. 1974, Steckhan 1977). 

A very old gas-solid bromination of tyrosine (280) [97] has been revisited and it gave a quantitative yield for the reaction of rac-280 [22]. The doubly bromi-nated hydrobromide rac-281 is spectroscopically pure after removal of included gases at 50 °C in a vacuum. Quite spectacular is the specific and quantitative waste-free gas-solid tetrabromination of tetraphenylethylene (282), which shows some signs of autocatalysis and requires rotation of the flask around a horizontal axis at room temperature for 12 h as the reactant and product gases require mixing [60]. The isomer-free tetrabromide 283 is an attractive starting point for dendrimer syntheses and inclusion studies (Scheme 40). Also 4-bro-mo antipyrin hydrobromide is quantitatively obtained from antipyrin(hydro-bromide) and bromine vapor [22]. 

---