Benzene 1,3,5-triphenyl

Treatment of these complexes with excess phenylacetylene leads ultimately to the symmetrical triphenyl benzene as the main product, but the intermediate adduct IV, Os3(CO)9L2, exists in three isomeric forms which are considered to be related to the osmacyclopentadiene complex Os3(CO)9[C2(C6H5)2]2, obtained from reaction of diphen-ylacetylene with the Os3(CO)i2. The structure of this complex has been established by X-ray crystallography (132) to be that shown in Fig. 21, with R = Rl = Rz = R3 = Ph. The three isomeric derivatives in the case of the phenylacetylene adduct arise from the various permutations of the phenyl and hydrogen groups around the osmacyclopentadiene ring. 

This procedure illustrates a general method for converting substituted pyrylium salts to nitrobenzene derivatives. The reaction has been the subject of several reviews. - The yields are generally high, and under these conditions only a single product is formed, in contrast to the nitration of 1,3,5-triphenyl-benzene. The preparation of 2,4,6-triphenylnitrobenzene from the corresponding pyrylium salt eliminates isomer separation problems, which are encountered when the direct nitration procedure is used. Also, labeled compounds can readily be prepared by this method. ... 

As isotactic polystyrene has a simUar crystal structure to that of polyethylene, the concept of the intramolecular cydization may be applied to the degradation of the former to account for the formation of the products of degradation. Let the three-unit one turn radical form the cyclic compound (VIH) by the interaction of the Qi and C 6 atoms. The cyclic compound (VIII) may lose hydrogens to other free radicsds to form 1,3,5-triphenyl-benzene (IX). 

The 2,4,6-triphenylpyrylium ion reacts with nitromethane to give the dienone 39. This is followed by an intramolecular nitro-aldol condensation forming 2,4,6-triphenylnitrobenzene 40. By way of the ring-opened phosphorane 41, action of phosphorylidene produces the 2-substituted 1,3,5-triphenyl-benzene 42 ... 

Deuteron shifts have also been measured for the negative ions of biphenyl-dio naphthalene,and triphenyl benzene. 5 a striking result was the determination of deuteron quadrupole coupling via the comparison of the line widths, as mentioned earlier. The line widths of the deuterium peaks in naphthalene-do did not vary linearly with a2, as is expected from Equations 17 and 18. However, the variation in line widths was accounted for by considering the contribution of the dipolar interaction. If one uses the proton line width to estimate (1/T2)fc (1/T2)d < n estimate (1/T2)q. The only un-... 

Mass spectral analysis of these materials indicated the presence of triphenylbenzenes and phenylnaphthalenes. As a comparison the reaction of phenylacetylene as a k0% solution in benzene or methanol under high pressure at 220°C was recently reported 3 to give (75 ) polymers, (3%) phenylnaphthalenes, and 20 triphenyl benzene isomers. The thermally induced reaction of the terminal acetylene groups is very complex and will require a significant research effort for the exact mechanistic determination. 

The 2,4,6-triphenyl pyrylium ion reacts (a) with nitromethane in the presence of a base to give 2,4,6-triphenyl-nitrobenzene (43) via intermediate 42 and its intramolecular Henry reaction and (b) with P-ylides to give 1,3,5-triphenyl benzene derivatives 45 via intermediate 44 and its intramolecular Wittig olefination ... 

The synthesis of polyarylenesulfones containing links of 1,3,5-triphenyl-benzene can be performed [182] by oxidation of polyarylene thioesters. Obtained polyarylenesulfones have T. = 265-329 °C and temperature of 5%... 

The thermal stability has been monitored by thermogravimetric measurements. In most cases the onset of decomposition is in the range from 330-370 °C. The oxadiazole compound 32 with a triphenyl benzene core shows a somewhat higher thermal stability up to 410 °C. 

FIGURE 11.18 Solubility of aromatic solids in benzene [19]. The solid line is a best linear fit of the experimental data. The compounds fisted from B to J in the figure are pyrene, fluorene, fluoranthene, hiphenyl, acenaphthene, phenanthrene, o-terphenyl, m-terphenyl, and anthracene. The authors also show tabular solubility values for triphenylene, p-terphenyl, and 1,3,5-triphenyl benzene, which are not shown in the above plot (orthe plot in the original article). Those values differ from the data fit line by up to a factor of 3. The authors cite the fact that these three compounds have fusion temperatures much higher than those of the compounds shown as the probable reason for this disagreement. 

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