Bis-phenylethynyl-benzene

Similarly large anisotropies were later reported for highly emissive blends of alkoxy-substituted bis(phenylethynyl)benzene derivatives and polyolefins such as linear low-density polyethylene (LLDPE) and isotactic polypropylene (z-PP) [8,9]. The latter systems reach high levels of anisotropy at very low draw ratios, which is advantageous from a processing point of view. 

Analogously, aromatic high molecular weight poly(pyridone)s have been obtained using terminal and internal aromatic diynes, e.g. 1,4-diethynylbenzene [98] and l,4-bis(phenylethynyl)benzene [99] respectively, for 1 1 cycloaddition copolymerisation with isocyanates. 

Figure 15-21. TD/BP86/cc-pVDZ energies at CIS geometries of 1,4-Bis(phenylethynyl)benzene (PEB) as a function of CCC angle. Inset the TTCT -state structure at the minimum energy along with the calculated vibrational frequencies (in cm-1) of the triple bonds. (From Ref. [40].)...

Irradiation of / -bis(phenylethynyl)benzene (372) gives one azulene derivative 373 and a naphthalene derivative 374. Formation of 374 can be accounted for in terms of a bicyclobutane intermediate similar to 371. Cleavage of bonds corresponding to c and e in 371 and subsequent hydrogen migration would lead to 374 - . 

Behaviour similar to that of 365 is observed with o-dipropynylbenzene (375) and l,2-bis(phenylethynyl)cyclohexene (376), but o-bis(arylethynyl)benzenes (377) show different behaviour - c -Bis(phenylethynyl)benzene (377, Ar = Ph) gives a... 

Rowan, Mather et al. [63—65] have examined the use of complementary nu-cleobase interactions to allow the formation of supramolecular LC materials of the main type shown in Fig. 3a and b. In these cases, a rod-like mesogen-bis(phenylethynyl)benzene-was functionalized symmetrically (homoditopi-cally) with thymine (T) or N6-anisoyl protected adenine (AAn) using alkoxy spacers of varying length to yield molecules of the type Bp-1-Bp, where Bp depicts the variable nucleobase moiety, AAn or T (Fig. 5). 

Further interest in DNA hairpins has examined systems separated by the alkyne (56). The formation and decay of contact radical ion pairs was studied. The photophysical properties of l,3-bis(phenylethynyl)benzene have been reas-sessed. ... 

An analogous coupling reaction of 161 with phenylacetylene under tetra-kis(triphenylphosphane)palladium and copper iodide co-catalysis [108] yielded the double-layered l,4-bis(phenylethynyl)benzene system 164 [107b]. 

The ZINDO/CI/SOS method has also been used by Liu et a/. in a study of for 4-(dicyanomethylene)-2,6-bis-(2 -thiophene-vinyl)pyran and its derivatives by Fu et to study unsymmetric bis(phenylethynyl)benzene derivatives and... 

From diethynylbenzene and aromatic or aliphatic isocyanates also copolymers are obtained. Aryl isocyanates produce 1 1 copolymers using equimolar amounts of the monomers. An excess of aliphatic isocyanates is necessary to give the 1 1 copolymers (64). Similarly, from l,4-bis(phenylethynyl)benzene and alkyl-or aryl isocyanates rigid poly(2-pyridones) are obtained (65). Soluble ladder poly(2-pyridones) are obtained from macrocyclic diynes and aryl- or alkyl isocyanates (66). 

Solns. of o-bis(phenylethynyl)benzene and sulfur dichloride each in dry methylene chloride added simultaneously during 45 min, to stirred refluxing methylene chloride, and refluxing continued 15 min. 10-(a-dilorobenzylidene)benz[b]-indeno[2,l-d]thiophene. Y 90.3%. T.J. Barton, A. J. Nelson, and J. Clardy, J. Org. Chem. 36, 3995 (1971). 

It appears that the addition of ethynes to the carbonyl group in quinones is more efficient than the corresponding ethene process because irradiation of BQ or NQ in the presence of the eneyne 65 preferentially yields quinone methides. The photoaddition of l,4-bis(phenylethynyl)benzene to BQ in dichlo-romethane solution gives the quinone methide 66. However, the expected cyclobutene formation between duroquinone and 1,4-diethynylbenzene is somewhat more complex and affords not only 67, but also the ring-opened isomer 68 as well as the 2 1 adducts 69 and 70 in yields of 17,19,15, and 30%, respectively. ... 

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