Poly para-phenylene s

At about die same time, die application of the Suzuki coupling, the crosscoupling of boronic acids widi aryl-alkenyl halides in die presence of a base and a catalytic amount of palladium catalyst (Scheme 9.12),16 for step-growth polymerization also appeared. Schliiter et al. reported die synthesis of soluble poly(para-phenylene)s by using the Suzuki coupling condition in 1989 (Scheme 9.13).17 Because aryl-alkenyl boronic acids are readily available and moisture stable, the Suzuki coupling became one of die most commonly used mediods for die synthesis of a variety of polymers.18... 

Poly f p-oxybenzoyl-co-p-phenylene isophthalate]), 113-114 Poly(2,2 -oxydiethylene adipate), 29 Polyoxymethylene glycol, aqueous, 377 Poly(oxytetramethylene) (PTMO), 53 Poly (p-pheny lene). See also Poly(para-phenylene)s dendronized, 520-521 synthesis of, 491-494 synthesis of water-soluble, 493 Poly(phenylene ether sulfone) chains,... 

Poly(phenyleneethynylene)s, 482 optically active, 516-517 synthesis of, 496-500, 502 Poly(m-phenylene isophthalamide), 136 synthesis of, 185-186 Poly(l,4-phenylene terephthalate) liquid crystalline polymers, 51 Poly(para-phenylene)s, 472. See also Poly (p -pheny lene)... 

An important challenge in the design of novel conjugated polymers is the synthesis of materials with tailor-made solid-state electronic properties. This section outlines the synthesis of the most significant classes of poly(para-phenylenevinylene)s (PPVs), poly(para-phenylene)s (PPPs), and related structures. Furthermore, this review demonstrates that the chromophoric and electronic properties of conjugated rr-systems are sensitive to their molecular and supra-molecular architecture. 

Keywords Poly(para-phenylene)s, Poly(para-phenylenevinylene)s, Oligomers, Photoluminescence, Electroluminescence, Light emitting diodes. 

Ladder-Type Oligo- and Poly(para-phenylene)s.177... 

The requirements outlined above represent a considerable challenge for polymer synthesis. This article describes an appealing development, based on two central substance-classes of conjugated polymers, poly(para-phenylene)s and poly(para-phenylenevinylene)s. 

Poly(para-phenylene)s PPPs and other polyarylenes represent structure-classes of conjugated polyhydrocarbons which are currently under intensive investigation [7]. This, in turn, is the result of important advances that have been made in the chemistry of aromatic compounds in recent years. 

Based on the results of the synthesis of oligo- and poly(para-phenylene)s PPPs (see Sects. 2.1-2.3) several investigators have studied the generation of other oligo- and polyarylenes. 

G Grem, V Martin, F Meghdadi, C Paar, J Stampfl, J Sturm, S Tasch, and G Leising, Stable poly(para-phenylene)s and their application in organic light emitting devices, Synth. Met., 71 2193-2194, 1995. 

Structurally Defined Poly(para-phenylene)s with "Step-Ladder" Structure... 

Polyphenylene-type Emissive Materials Poly(para-phenylene)s, Polyfluorenes, and Ladder Polymers... 

Rehahn M, Schliiter AD, Wegner G (1990) Soluble poly(para-phenylene)s 3. Variation of the length and the density of the solubilizing side chains. Makromol Chem 191 1991-2003... 

Rehahn, M., Schluter, A.-D., Wegner, G. Soluble poly(para-phenylene)s. 1. Extension of the Yamamoto synthesis to dibromobenzenes substituted with flexible side chains. Polymer 30(6), 1054-1059 (1989)... 

Another class of chemically exceptionally stable polymers are the poly(para-phenylene)s. In addition, they are stiff, rod-Uke polymers. This feature usually tends to cause insolubihty of polymers, which is an attractive approach rod-like polymers can be expected to be insoluble in water at much higher lEC values than polymers consisting of flexible chains, such as poly(arylene ether)s. Since proton conductivity depends on lEC, such polymers have the potential to form membranes with high conductivity at relatively low degrees of swelling and good dimensional and mechanical stability. 

The poly(para-phenylenes)s can be considered rigid rod polymers, which distinguishes them from aU other types of polymers typically used for proton conducting membranes, possibly with the exception of certain polyimides. A striking consequence of the rigid rod structure is the fact that the poly(para-... 

Probably because of limited molar mass, the brittleness of these poly(para-phenylene)s can be compensated by incorporating them as sulfonated segments into block copolymers with poly(aryl ether sulfone)s (78). As for the poly(aryl ether ketone) block copolymers, water uptake is reduced while relatively high conductivity (considering the lEC) is maintained [78]. 

Another method [77] for the synthesis of poly(para-phenylene)s utihzes a reaction which was already successfully used by Stille [83-85] in the 1960s Diels-Alder reaction (Fig. 15). 

Table 5 lEC, water uptake and conductivity of selected poly(para-phenylene)s [77-80]... 

Table 5 summarizes characterization data of some poly(para-phenylene)s. Values for Nafion are added for comparison. 

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