Poly carbazole substituted

J.-F. Morin, S. Beaupre, M. Leclerc, I. Levesque, and M. D lorio, Blue light-emitting devices from new conjugated poly(iV-substituted-2,7-carbazole) derivatives, Appl. Phys. Lett., 80 341-343, 2002. 

Fig. 22a-d. Examples of polymers used in photorefractive composites a poly (vinylcarbazolc) (PVK) b carbazole substituted polysiloxarie (PSX) c poly(methylmethacrylate-co-tricy-clodecylmethacrylate-co-N-cyclohexylmaleimide-co-benzyl methacrylate) (PTCB) d thioxanthene containing polymer (P-THEA)... 

It is interesting to note that striae have also been observed in certain polymer solutions stressed by shear between glass plates [2-8]. Marcher et al. [10] observed these patterns in carbazole-substituted helical poly-amino acid solutions stressed by shear. These workers used Fourier transform infrared spectroscopy to calculate order parameters describing the degree of alignment and packing of the carbazole side chains. 

In the first instance, poly-a-amino acids with carbazole-substituted side chains were chosen for this purpose. Poly-a-amino acids are well known to be capable of forming lyotropic cholesteric phases due to their a-helical conformation. The formation of a homeotropic nematic phase, as shown schematically in Fig. 10, would give the desired morphology with the stacking of the carbazole rings in the plane of the cell. This is in essence the same morphology obtained with the carbazole-doped thermotropic... 

T. Ahn, S. Song, and H. Shim, Highly photoluminescent and blue-green electroluminescent polymers new silyl- and alkoxy-substituted poly(p-phenylene vinylene) related copolymers containing carbazole or fluorene groups, Macromolecules, 33 6764-6771, 2000. 

Most of the polymer modifications incorporating benzo-substituted pyrroles have been done with the dibenzo derivative, carbazole, primarily because of its well-known photocon-ductive properties. The modification reaction often involves a substitution reaction on some halogenated polymer. This substitution reaction can be quite facile. Poly(vinylbenzyl chloride), for example, reacts with the potassium salt of carbazole in DMF to yield the carbazole-functional polymer in 97% yield (76MI11110). 

FIGURE 1.2. Molecular structure of widely used it-conjugated and other polymers (a) poly(para-phenylene vinylene) (PPV) (b) a (solid line along backbone) and it ( clouds above and below the a line) electron probability densities in PPV (c) poly(2-methoxy-5-(2 -ethyl)-hexoxy-l,4-phenylene vinylene) (MEH-PPV) (d) polyaniline (PANI) (d.l) leucoemeraldine base (LEB), (d.2) emeraldine base (EB), (d.3) pernigraniline base (PNB) (e) poly(3,4-ethylene dioxy-2,4-thiophene)-polystyrene sulfonate (PEDOT-PSS) (f) poly(IV-vinyl carbazole) (PVK) (g) poly(methyl methacrylate) (PMMA) (h) methyl-bridged ladder-type poly(jf-phenylene) (m-LPPP) (i) poly(3-alkyl thiophenes) (P3ATs) (j) polyfluorenes (PFOs) (k) diphenyl-substituted frares -polyacetylenes (f-(CH)x) or poly (diphenyl acetylene) (PDPA). 

In order to co-polymerize the IC unit, Suzuki and Stille polymerizations have been used. First, Blouin et al. [94] were able to obtain polyindolo[3,2-fr]-carbazole derivatives with bithiophene or biEDOT as co-monomers. Unfortunately, these studies demonstrated a relatively low oxidation potential for these polymers (especially for P35 and P37), limiting their applications in OFETs and PCs. However, for doped state applications, these polymers may exhibit interesting properties [35]. For instance, when copolymerized with bithiophene, the resulting copolymer shows a good electrical conductivity (as high as 0.7 Scm 1) but a low Seebeck coefficient of 4.3 iV K 1 [35]. Finally, the UV-Vis absorption maxima are similar for poly(2,8-indolocarbazole-a/f-bithiophene) and poly(2,8-indolocarbazole-a/f-bis(3,4-ethylenedioxythiophene)). A broad absorption band is centered at 430 nm whereas, for the 3- and 9-substituted copolymers, the broad band is centered around 490-500 nm [94],... 

Even in the absence of substitution on the a-carbon, extremely large side groups attached directly to the polymer chain, as in poly(N-vinyl carbazole), can cause a large tacticity effect. 

Malhotra SL (1983) Ultrasonic modification of polymers. 2. Degradation of polystyrene, substituted polystyrene, and poly(n-vinyl carbazole) in the presence of flexible chain polymers. J Macromol Sci A A18 1055-1085... 

The Ullmann reaction was used in the coupling of a wide variety of aryl halides, Ar-X, where the Ar includes mono-, di-, poly-substituted phenyl [4,5,14], naphthalene [4,5,15,16], azulene [17], pyridine [18], pyrimidine [19], thiophene [4,5,20], carbazole [21], and even ferrocene [22], while X = I, Br, Cl. The reaction was successfully used in the intramolecular cyclization reactions affording four- [23], five- [24], six-membered [25], and some other larger rings [6]. Selected examples where halides 10-13 were converted to biaryls 14-17 are given in the Scheme 2 [14,16,17,19]. 

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