Polymers ladder-type

U. Scherf, in Handbook of Conducting Polymers, 2nd edn, (Eds. T. Skolhcim, J.R. Reynolds), Marcel Dekkcr, New York 1997, Chapter 14 (Conjugated Ladder-Type Structures), p. 363. 

Figure 9-1. Materials overview a few sclcclcd conjugated polymers and Ihcir properties have been compiled and ihe following abbreviations arc used DO-PPP...Poly(2-decyloxy-l,4-phcnylcnc), EHO-PPP...Poly(2-(2 -elhylliexyloxy)-l,4-phcnylenc), CN-PPP... Poly(2-(6 -cyano-6 -incthyl-licplyloxy)-l,4-phcnylene), m-LPPP... methyl-substituted ladder-type Poly( 1,4-phenylcne), and PLQY=phololuinincs-ecncc quanluni yield.

Fahnenstich U., Koch K. H., Pollmann M., Scherf U., Wagner M., Wegener S., Muellen K. Design of Novel Strnctnrally Defined Ladder-Type Polymers Makro-mol. Chem., Macromol. Symp. 1992 54/55 465—476... 

Ladder-Type Oligo- and Poly(pora-phenylene)s Polymers... 

In 1993, Scherf and Chmil described the first synthesis of a ladder-type poly(pflra-phenylene-czs-vinylene) (116) [138]. On the one hand, ladder polymer 116 represents, a planar poly(phenylene) containing additional vinylene bridges on the other hand, it is a poly(phenylenevinylene) with aryl-aryl linkages in the polymeric main chain. The target macromolecules, as fully aromatic ladder polymers, are composed of all-carbon six-membered rings in the double-stranded main chain (an example of angularly annelated poly(acene)s). 

Schliiter et al. have isolated the beltene derivative 20, which was developed as byproduct when synthesizing the ladder-type polymer 21 by a repeated Diels-Alder reaction (Fig. 11). The monomer 19 can act both as diene and as dienophil [41]. The iterative Diels-Alder method is however limited by the decreasing solubility of the products of higher molecular masses. 

As the next step in this way, Mullen and coworkers [608] have reported PPP-type polymers 512, containing planar pentaphenylene blocks. As expected, the emission maximum (Apl = 445 nm) of 512 was found between those of indenofluorene 510 (432-434 nm) and completely planar ladder-type PPP (450 nm) (see Section 2.5.2) [608]. Single-layer PLEDs ITO/PEDOT/512b/Ca/Al showed stable pure-blue emission with brightness in excess of 200cd/m2 (at 7 V) (Chart 2.121). 

J. Jacob, S. Sax, T. Piok, E.J.W. List, A.C. Grimsdale, and K. Mullen, Ladder-type pentapheny-lenes and their polymers efficient blue-light emitters and electron-accepting materials via a common intermediate, J. Am. Chem. Soc., 126 6987-6995, 2004. 

XH Yang, D Neher, U Scherf, SA Bagnich, and H Bassler, Polymer electrophorescent devices utilizing a ladder-type poly(para-phenylene) host, J. Appl. Phys., 93 4413 -419, 2003. 

Fig Polymer chains, (a) linear, (b) branched, (c) comb-type, (d) ladder-type, (e) net work. 

Hydrolytic polycondensation of trifunctional monomers of the type XSiYj leads to cross-linked three-dimensional as well as network and cis-syndiotactic (ladder-type) polymers, (XSiOj 5) With increasing amount of solvent, however, the cor-... 

Upon electron impact of different energy, oligoforganylsilsesquioxanes) may polymerize with either abstraction of hydrocarbon radicals (C—C bond rupture) and formation of ladder-type molecules cross-linked by alkylene bridges or cleavage of siloxane bonds and formation of polymers of irregular structure... 

For high molecular weight, Mn and M /Mn do not change in the course of polymerization up to about 60% conversion. These results confirm that under proper conditions (polymerization at moderate temperature, template of high enough molecular weight, moderate concentration of substrates) ladder-type polymers can be obtained by template polymerization of multiacrylates or methacrylates. 

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