Polyphenylene derivatives

Dibromoterphenyl compounds (72i) can be prepared from zirconacyclopentadienes. They polymerize in the presence of a Ni catalyst to afford polyphenylene derivatives 87, as shown in Eq. 2.58 [42]. 

Novel, hyper-branched polyphenylenes 20 have been prepared by the selfcoupling of 3,5-dibromophenylboronic acid in the presence of Pd(PPh3)4 as shown in Scheme 25 [90,91]. (The monomer was prepared by treatment of the monolithiate of 1,3,5-triboromobenzene with trimethyl borate.) The hyper-branched polymer was found to be organic soluble, and could be converted to a water-soluble, polyphenylene derivative by treatment with butyl lithium followed by quenching with C02. The water-soluble nature of such hyper-branched polyphenylenes has made them suitable candidates for use in various applications such as unimolecular micelles. 

Rigid-rod compositions consisting of polyphenylene derivatives were used by Goldberg [2] as advanced thermoplastics in preparing orthodontic wire. 

For the devices presented here, the wrapped copolymer PPyVPV and a wrapped copolymer of poly thiophene and polyphenylene derivative, PTP, were used as the emitting materials SPAN and EB were used as the redox materials ITO and Al were used as electrodes. Figure 9.11 shows the schematic diagram of the device structure of the color-variable bipolar/ac light-emitting devices. 

In spite of an irregular polymer architecture, some amphiphilic, hyperbranched polyphenylene derivatives were found to assemble, forming quite uniform Langmuir monolayers at the water/air interface. For example, 3J assembled into a monolayer at the water/air interface and provided a surface similar to the Langmuir film of fatty acids in the nucleating of mineral crystallization on the water/air interface. 

K. Suda, K. Akagi, Electro-optical behavior of ferroelectric liquid crystalline polyphenylene derivatives. J. Polym. Sci. Part A Polym. Chem. 46, 3591-3610 (2008)... 

Recently, liquid-crystalline polyphenylene derivatives have been synthesized through substitution of a fluorine-containing chiral liquid-crystalline group into side chains, with an aim to develop ferroelectric liquid-crystalline conjugated polymers (Fig. 5 Suda and Akagi 2008). These are attracting interest because they can afford anisotropies in electrical and optical properties when they are macroscopically aligned. This study also elucidated that PPP can be used to prepare new types of polymer materials. 

An analogous coupling with organoboron compounds is called Suzuki coupling. This reaction is even less sensitive to water in fact, it is often carried out in water or water-containing solvents. Oxygen should, however, be excluded. A good example is the preparation of the first water-soluble polyphenylene derivative (Fig. 8e). 

Coating pull-off strengths were measured for polyphenylenes derived from the acid-catalyzed aromatlzatlons of CHD-dlacetate polymers on both a glass and a copper surface using a PATTI Adhesive Tester, In this test an aluminum pull tab Is cemented to the exposed film surface with epoxy resin and the tab Is pulled from the surface In a perpendicular dlrectlon. ... 

The A2 + B3 polymerization was carried out at different molar ratios of A2 and B3 monomers (A2 B3 = 1 1, 3 2, 2 1, and 3 1). The molar masses of polymers obtained by the A2 + B3 approach were lower = 2,500-68,000 Da, as recorded by refractive index detector) than those of AB2 polymers (37 = 47,000-660,000 Da, as recorded by light scattering detector) due to the off-stoichiometric functional ratios. For AB2-type polymerization, a higher molar mass was attained at longer reaction times. All the AB2 polymers showed a bimodal weight distribution whereas all the polyphenylenes derived from the A2 and B3 monomers showed a... 

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