Poly conjugated synthesis

J. Roncali, Conjugated poly(thiophenes) synthesis, functionalization, and applications, Chem. Rev., 92 711-738, 1992. 

Heterocycle-based electroconductive polymers , Berlin, A., Plastic Eng. (N.Y.) (Electrical and Optical Polymer Systems), 1998, 45, 47 Heterocycle-based electric conductors , Pagani, G. A., Heterocycles, 1994, 37, 2069 Conjugated poly(thiophenes) synthesis, functionalisation and applications , Roncali, J., Chem. Rev., 1992, 92, 711. 

Acetaldehyde also engaged in other conjugate additions with poly-conjugated substrates, such as nitrodienynes and nitroenynes. Interestingly, only 1,4-additions were observed and no 1,6- or 1,8-addition occurred. The utility of the products was demonstrated by the enantioselective total synthesis of (- -)-a-lycorane (Scheme 8.2). ... 

Roncali, J. [1992], Conjugated poly[thiophenes) Synthesis, functionalization, and appiications, Chem. Rev., 92, pp. 711-738. Gadgii, B., Damlin, R, Aaritaio, T, Kankare, ]., and Kvarnstrdm, C. (2013). Electrosynthesis and characterization of viologen cross linked thiophene copolymer, Electrochim. Acta, 97, pp. 378-385. Nalwa, H. S. (2001). Advanced Functional Molecules and Polymers Electronic and Photonic Properties, 3 (Gordon and Breach Science Publishers, Amsterdam, The Netherlands]. 

J. Roncah, Conjugated Poly(Thiophenes) Synthesis, Functionalization, and Apphcations. Chem. Rev. 1992,92,711-738. 

Bi, X., Shi, X., Majoros, I.J., Shukla, R., Baker, J.R., 2007. Multifunctional poly(amidoamine) dendrimer-taxol conjugates synthesis, characterization and stability. J. Comput. Theor. Nanosci. 4 (6), 1179-1187. 

Poly(l,4-phenylenevinylene) (PPV) and its derivatives have been the subject of many studies on their structures and electrical, optical, and electroluminescence properties [113-115]. It is expected that the materials with donor and acceptor groups attached on a PPV backbone can maintain the poled state unrelaxed once properly poled, because PPV has a highly rigid backbone owing to its poly conjugated structure. A series of such types of polymers have been reported by Jin et al. [116]. The synthesis of one of these polymers (poly[ 2-methoxy-5-(2-(4-nitrophenyl)ethenyl)-l,4-phenyl-enevinylene -co-(l,4-phenylenevinylene)]) is shown in Scheme 5. The dy.y, of 4.2 pm V was obtained in the contact poled polymers. The SHG signal remained constant over a period of more than 1 month at room temperature. 

There have been very few examples of PTV derivatives substituted at the vinylene position. One example poly(2,5-thienylene-1,2-dimethoxy-ethenylene) 102 has been documented by Geise and co-workers and its synthesis is outlined in Scheme 1-32 [133]. Thiophene-2,5-dicarboxaldehyde 99 is polymerized using a benzoin condensation the polyacyloin precursor 100 was treated with base to obtain polydianion 101. Subsequent treatment with dimethyl sulfate affords 102, which is soluble in solvents such as chloroform, methanol, and DMF. The molar mass of the polymer obtained is rather low (M = 1010) and its band gap ( ,.=2.13 eV) is substantially blue-shifted relative to PTV itself. Despite the low effective conjugation, the material is reasonably conductive when doped with l2 (cr=0.4 S cm 1). 

On the other hand, it has also become clear that a materials-oriented synthesis of conjugated poly(phenylene)s cannot narrow its attention to properties of molecules only in solution, but has to include aspects of processing and supramolecu-lar ordering as well. The rigid-rod character of PPPs therefore suggests the use of chain stiffness as a structure-forming principle in the design of supramolecular motifs. 

This article, while not being intended to provide a full account of poly(arylene)s, emphasises the synthetic aspects. The synthesis of conjugated oligomers and polymers is, however, always part of an interdisciplinaiy approach with their active physical function being a key concern. In that sense the research being reviewed above concentrates on physical properties rather than playing with exotic chemical structures. 

The sulfonium precursor route may also be applied to alkoxy-substituted PPVs, but a dehydrohalogenation-condensation polymerization route, pioneered by Gilch, is favored 37]. The polymerization again proceeds via a quinomethide intermediate, but die syndicsis of the conjugated polymer requires only two steps and proceeds often in improved yields. The synthesis of the much-studied poly 2-methoxy-5-(2-ethylhexyloxy)-l,4-phenylene vinylene], MEH-PPV 15 is outlined in Scheme 1-5 33, 35]. The solubility of MEH-PPV is believed to be enhanced by the branched nature of its side-chain. 

At this point it might be appropriate to comment on the conflicting requirements of the synthesis. The large interest which other conjugated polymers such as polypyrrole, polyanilinc or poly(parattracted originates, firstly, from their attractive physical properties, but also from the sim-... 

In Figure 8-1 we show the chemical structure of m-LPPP. The increase in conjugation and the reduction of geometrical defects was the main motivation to incorporate a poly(/ -phenylene)(PPP) backbone into a ladder polymer structure [21]. Due to the side groups attached to the PPP main chain excellent solubility in nonpolar solvents is achieved. This is the prerequisite for producing polymer films of high optical quality. A detailed presentation of the synthesis, sample preparation,... 

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