Poly- 2,5-dimethoxy-/?-phenylene

The preparation of poly(2,5 dimethoxy phenylene vinylene)(DM-PPV) utilized the xanthate precursor route. Many similarities exist between the PPV xanthate thermal elimination and this PPV derivative. Previous studies had attempted to synthesis DM-PPV using the SPR method. The SPR resulted in gel formation during dialysis so that film casting was not possible. The XPR was successful in preparing precursor films that can be thermally converted to DM-PPV. The derivatives of PPV are useful to prepare a polymer with a shift in the absorbance and photoluminescence maximum. DM-PPV exhibits an 100 nm red shift as compared with PPV synthesized via the XPR. 

Figure 5. Three-dimensional temperature-infrared frequency-intensity plot of the reaction byproducts of the thermal elimination from xanthate poly(2,5-dimethoxy phenylene vinylene) precursor...

I. D. Parker, R. W. Gymer, M. G. Harrison, R. H. Friend, and H. Ahmed, Fabrication of a novel electro-optical intensity modulator from the conjugated polymer. poly(2,5-dimethoxy-/ -phenylene vinylene), Appl. Phys. Lett. 62 1519 (1993). 

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... 

Abstract In situ spectroscopy is an important tool to characterize polymers synthesized via a precursor route. Highly conjugated polymers such as po y(p-phenylene vinylene) (PPV) and PPV derivatives are commonly prepared from a precursor polymer because the final polymers are very insoluble and intractable. Preparation in the precursor form enables the polymer materials to be cast as films. The PPV polymers are obtained from the precursor forms using a thermal elimination reaction. The exact conditions of the reaction are important as they influence the properties of the resultant polymer. The details of this thermal elimination reaction have been analyzed using thermal gravimetric analysis (TGA) coupled with infrared analysis of the evolved gas products. In situ infrared spectroscopy of the precursor films during thermal conversion to the polymers has provided further details about the elimination reaction. We have characterized PPV synthesized from a tetrahydrothiophenium monomer (sulfonium precursor route) and via the xanthate precursor route. PPV derivatives under study include poly(2,5-dimethoxy-p-phenylene vinylene) and poly(phenoxy phenylene vinylene). 

Key words poly(p-phenylene vinylene), PPV, thermal elimination, precursor route, poly(2,5-dimethoxy-p-phenylene vinylene), poly(phenoxy phenylene vinylene)... 

The XPR has been used to synthesize poIy(2,5 dimethoxy p-phenylene vinylene)(DM-PPV) and the reaction is the same as shown in Figure 2 except that methoxy substituents are present at the 2 and 5 positions of the phenylene ring. The chlorine precursor route (CPR) is used to prepare poly(phenoxy phenylene vinylene) (PO-PPV) and the reaction is shown in Figures. ... 

Reynolds et al. [38] synthesized and characterized poly(di-2-thienylphenylene), poly(di-2-thienyl-2,5-di-methylphenylene) and poly(di-thienyl-2,5-dimethoxy-phenylene) to study the effect of substitution on polymer structure. These electrically conducting (ca. 1 S/cm) polymers show electrochemical and optical properties that are similar to those of PT. In addition, substitution on the benzene ring enables the synthesis and characterization of additional copolymers in the series [39]. 

P. L. Burn, et al.. Precursor route chemistry and electronic properties of poly(p-phenylenevinylene), poly[(2,5-dimethyl-/ -phenylene)vinylene] and poly-f(2,5-dimethoxy-/ -phenylene)vinylene], J. Chem. Soc. Perkin Trans. 7 3225 (1992). 

Katsuya et al. [5 published the oxidative coupling (agent copper(II) chloride/ aluminum chloride) of electron-rich benzene derivatives such as 2,5-dimethoxy-benzene to poly(2,5-dimethoxy-1,4-phenylene) (2). The resulting polymer is only soluble in concentrated sulfuric acid, and is fusible at 320r C. Ueda et al. 16] described the coupling of the same monomer with iron(III) chloride/aluminum chloride. The polymers obtained by the authors were not thoroughly para-linked. 

Figure 106 Experimental j—U characteristics of polymer films for various temperatures (a) and two different thickness (o,A) samples at room temperature (b). (a) Steady-state currents in poly(dialkoxy-p-phenylene vinylene) (PPV) (the layer thickness d = 125 nm). After Ref. 471. (b) Response current to 10 ps rectangular voltage pulses in poly[2-5-dimethoxy-l,4-phenylene-l,2-ethenylene-2methoxy-5-(2-ethylhexyloxy)-l,4-phenylene-l,2-ethenylene (M3EH-PPV) AU = U-Ubi, where U is the applied voltage and f/bi is the built-in potential due to a difference in the work functions of the electrodes. After Ref. 472. Copyright 2000 American Institute of Physics.

The reaction proceeds via quinodimethane intermediates. In general, the reaction is carried out in an aprotic solvent, such as DMF. However, for the preparation of the soluble poly(2,5-dimethoxy-l,4-phenylene vin-ylene), an undivided flow cell with constant current at a lead cathode and aqueous DMF can be used. 

MEH-PPV Poly(2-methoxy-5-(2 -ethylhexyloxy)-l,4-phenylene vinylene) Poly(2-methoxy-5-(2 -ethylhexyloxy)-1,4-phenylene vinylene 2,5-dimethoxy-l,4-phen-ylene vinylene) b... 

Poly(9,9 -dihexylfluorene-2,7-divinylene-m-phenylene vinylene-stat-p-phenyl-ene vinylene), 30, 31, 51 Poly(2,5-dimethoxy-l,4-phenylene vinylene), 95 Poly(2-(A, A -dimethylamino) phenylene vinylene), 100 Poly(2-dimethyloctylsilyl)-phenylene vinylene, 99 Poly(9,9-dioctylfluorene), 31, 110 Poly(9,9-dioctylfluorene-co-lluorenone), 30 Poly(4,4 -diphenyl ether-l,3,4-oxadiazole), 334 Poly(2,6-diphenyl-l,4-phenylene oxide), 152 Poly(2,6-diphenyl-l-4-phenylene oxide), 141 Poly(dithiathianthrene), 189 Poly(2-dodecyl-p-phenylene), 36 Poly(AT-epoxypropyl)carbazole, 13 Poly(ether ether ketone), 209 Poly(ether imide), 154, 214, 264, 376 Pol(yether ketone), 213 Poly(ether nitrile), 227 Poly(ethersulfone), 209, 264... 

Gowri, R., et al. 1998. Synthesis of novel poly[(2,5-dimethoxy-p-phenylene)vinylene] precursors having two eliminatable groups An approach for the control of conjugation length. Macromolecules 31 1819. 

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