PHENYLENE ACETYLENE COPOLYMER

Week [203] developed a monomer salen complex linked to a norbomene via a stable phenylene-acetylene linker and its subsequent polymerization by means of the controlled ROMP method using 3 generation Grubb s catalyst (Scheme 137). This polymerization methodology led to fully functionalized immobilized metal-salen catalyst. By this way, the supported catalyst showed catalytic activities and stereoselectivities similar to the nonsupported Jacobsen catalyst. Moreover, activities and selectivities seemed to depend on the density of the catalytic moieties homopolymer 324 were less selective than their copolymer analogs 325. For example, AE of 1,2-dihydronaphtalene led in both cases to total conversion and 76% ee for the homopolymer 324 vs 81% ee for copolymer 325a. Recycle was possible and after 3 recyles a drastic decrease in ee was observed. AE of dihydronaphtalene led to 81% ee for the first cycle vs 6% ee for the third one. 

A second group of polyaromatic polymers have also been studied These include poly(phenylene vinylene) (15), which may be considered an acetylene copolymer, and its derivatives these polymers are dopable to conductivities up to 3 s/cmj Poly(2,5-thienyltye) (16) yields a conductivity of 10 s/cm with iodine Recently poly(N-methyl-3,3 -carbazolyl (17) was synthesized and upon treatment with iodine yielded a conductivity of 1 s/cm. Polymers (18) containing phenylene and sulfur nitride linkages are able to yield relatively high conductivities upon oxidation ... 

Common conductive polymers are poly acetylene, polyphenylene, poly-(phenylene sulfide), polypyrrole, and polyvinylcarba2ole (123) (see Electrically conductive polymers). A static-dissipative polymer based on a polyether copolymer has been aimounced (124). In general, electroconductive polymers have proven to be expensive and difficult to process. In most cases they are blended with another polymer to improve the processibiUty. Conductive polymers have met with limited commercial success. 

PAVs, where electrically conductive films with good transparency are easily obtained from their precursor polymers, are one group of -conjugated polymers and regarded as an alternating copolymer of acetylene and arylene. They have variations in chemical structure such as poly(p-phenylene vinylene), (PPV), poly(2,5-thienylene vinylene), (PTV), and poly(2,5-dimethoxy-p-phenylene vinylene), (MOPPVY9-1D. They have... 

Poly(/7-phenylenevinylene) may be considered a regular copolymer of acetylene and benzene [128]. Electron structures of PA, poly(p-phenylene), and poly(p-phenylenevinylene) were studied by using UV photoelectron spectroscopy and quantum chemical calculations based on the valence effective Hamiltonian method. Excellent agreement between the theory and experiment allows a detailed description of the evolution of the electron structure in this polymer series. 

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