Oxadiazole-containing polymers

Q. Pei and Y. Yang, 1,3,4-Oxadiazole-containing polymers as electron-injection and blue electroluminescent materials in polymer light-emitting diodes, Chem. Mater., 7 1568-1575, 1995. 

Polyheterocycles can even be made by polymer analogous reactions. A good example of this is the formation of oxadiazole-containing polymers. Thus, Janietz et al. [86] prepared the precursor polymers 89 by the polycondensation of 90 with 91 and then dehydrated it with phosphorus oychloride to give the phenylene oxadiazole copolymers 69 (Scheme 6.21). 

Alternating oxadiazole-alkoxyphenylene polymer Figure 10.6 Electroluminescent Oxadiazole-Containing Polymers ... 

The oxadiazole-containing polymer has two absorption peaks at 370 nm and 414 nm. It also exhibits apho-toluminescentpeakat555 nm when excited at414 nm. 

Similar PPV-based copolymers with carbazole and fluorene units in the backbone 101 and 102 (and also similar copolymers with oxadiazole substituents 103 and 104) have been synthesized by Ree and coworkers [148], Much lower PL efficiency in films was found in this case for carbazole-containing polymers 102 and 104 (1-4%), when compared to materials prepared by Shim (95 and 96, 59-64%) (Chart 2.21). 

Z. Peng, Z. Bao, and M.E. Galvin, Oxadiazole-containing conjugated polymers for light-emitting diodes, Adv. Mater., 10 680-682, 1998. 

Alternatively, oxadiazole-containing dendrimers and starburst compounds have been synthesized that form stable glasses." The general methods of how to synthesize this type of polymers are reviewed in the... 

Zhou W, Yang X, Jia E, Wang X, Xu J, Ye G. Ultraviolet resistance of azo-containing poly(l, 3,4-oxadiazole) fibres. Polym Degrad Stab 2013 98(3) 691-6. 

Song, S.Y, T. Ahn, H.K. Shim, I.S. Song, and W.H. Kim. 2001. Synthesis and electroluminescence properties of ortho-, meta- and para-linked polymers containing oxadiazole unit. Polymer 42 (11) 4803-4811. 

FIGURE 47.17. Oxadiazole-containing EL polymers, (a) Poly(2,5-diphenylene-1,3,4-oxadiazole)-4,40-vinylene (b) alternating oxadiazole-a/t-alkoxyphenylene and a aliphatic spacer. 

Wang X, Wu JC, Xu HY, Wang P, Tang BZ (2008) Preparation and property of two soluble oxadiazole-containing functional polyacetylenes. J Polym Sci Part A Polym Chem 46 (6) 2072-2083. doi 10.1002/pola.22542... 

Examples of high temperature heterocycle containing polymers which have been modified by the incorporation of aryl ether linkages include imides (5), phenylquinoxalines (4,5), triazoles (6,7), benzoxazole (S,9), oxadiazoles 10,11), benzothiazoles (72), isoquinolines 13) and phthalazines (14). Recently, the synthesis of many of these polymers was accomplished by... 

Phenoxaphosphine ring-containing poly (1,3,4-oxa-diazoles) were synthesized by cyclodehydration of poly-hydrazides obtained from (BCPO) and aliphatic and aromatic dihydrazines [152]. All these polymers are soluble in formic acid, w-cresol and concentrated H2SO4. The polyhydrazides yield transparent and flexible films when cast from DMSO solution under reduced pressure at 80-100°C. The polyhydrazides exhibit reduced viscosities of 0.24-0.40 dl/g in DMAC. Phenoxaphosphine ring-containing oxadiazole polymers showed little degradation below 400°C. 

Scheme 1-14. Examples of a oxadiazole- and a quinoxatine-containing electron-transporting polymer.

---