Gilch polymerization

H Becker, H Spreitzer, K Ibrom, and W Kreuder, New insights into the microstructure of gilch-polymerized PPVs, Macromolecules, 32 4925-4932, 1999. 

The molecular weight of the polymers can be controlled (from ca. 50,000 to above 1,000,000) by changing the reaction temperature and time, the solvent, the concentration of the monomer, and the amount of base [39,40]. High molecular-weight polymers and a high content of trans double bonds are the reasons for the wide usage of Gilch polymerization in the synthesis of PPV homo- and copolymers. 

EL from tetraalkoxy-substituted PPV 20, synthesized by Gilch polymerization, was recently reported [84], A multilayer device ITO/PEDOT/20/PBD/LiF/Al with PBD as an ETL emits green-yellow light with a luminescent efficiency of 0.121m/W, a maximum brightness of 8200 cd/m2, and a turn-on voltage of 5 V. 

An important extension to phenyl-substituted PPVs was first reported by Tsutsui and coworkers [115], who used Gilch polymerization to synthesize fluorenyl-substituted PPVs (57,58,59) and studied their performance in PLEDs (Chart 2.11). Due to bulky but rigid fluorene substituents, these polymers have excellent solubility and yet are thermally stable up to 320°C and have a... 

T. Ahn, S. Ko, J. Lee, and H. Shim, Novel cyclohexylsiyl — or phenylsiyl-substituted poly(p-phe-nylene vinylene)s via the halogen precursor route and Gilch polymerization, Macromolecules, 35 3495-3505, 2002. 

Satyanarayana and Elsenbaumer attempted the Gilch polymerization of monomer 191 to afford poly(bipyridinevinylene), 192, with [Ru(bpy)2]2+ complexed to each bpy in the conjugated backbone (Scheme 4.46).117 Unfortunately, the polymer obtained from this reaction was insoluble, and thus difficult to characterize. A large red shift in the optical spectrum was observed, and thermogravimetric analysis and IR spectroscopy also supported the structure assigned. The conductivity of the blue-black product was 4.5 X 10 6Scm 1. 

More recently, we have synthesized a new series of multifunctional EL polymers, poly[l,4- 2-(3,3 -diheptyl-3,4-propylenedioxythiophene-2-yl) phenylenevinylene] (PDOT-PPV), which is a series of fully conjugated PPV derivatives with a PDOT moiety as a pendant group. The polymerization of the monomers is outlined in Scheme 1.4. The homo- and copolymerization of monomers was performed by fhe Gilch polymerization... 

J. Wiesecke and M. Rehahn. The effect of persistent TEMPO radicals on the Gilch polymerization. Macromol. Rapid Commun., 28 78-83,2007. 

The mechanism of formation is similar to the Gilch polymerization route. The resulting polymers exhibit a significantly higher molecular weight and have less structural defects as those prepared by the polycondensation route. 

Becker, H., Spreitzer, H., Ibrom, K., Kreuder, W., 1999. New insights into the microstructure of GILCH-polymerized PPVs. Macro molecules 32,4925-4932. 

The results of these lifetime and efficiency investigations have implied that the hahde-mediated defects must be considered whenever different synthesis conditions or different PPVs are to be screened. Furthermore, such results continue to cast doubt on the attention appHed to TBB defects in Gilch-polymerized PPVs. It must not be assumed, a priori, that any dehydrohalogenation achieved during the Gilch synthesis would be sufficient to exclude the impact of halide defects when, for example, the correlation between the extent of the TBB defects and the device hfetime is examined [49]. 

In this chapter, the common synthesis routes leading to technologically significant PPV derivatives used in modern organic electronics have been critically reviewed. In particular, a consistent picture has been presented of the mechanism of the Gilch polymerization leading to such PPVs. The reaction cascade involved includes ... 

Hontis, L., et al. 2001. The Gilch polymerization towards OGIGIO-PPV indications for a radical mechanism. Polymer 42 5793. 

Fan, Y.-L, and K.-F. Lin. 2005. Dependence of the luminescent properties and chain length of poly[2-methoxy-5-(2 -ethylhexyloxy)]-l,4-phenylene vinylene on the formation of cis-vinylene bonds during Gilch polymerization. / Polym Set A 43 2520. 

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