Cyclopenta bithiophenes

Like ordered CPs, random copolymers have also been prepared to cater optoelectronic and other applications [252,255-258,450,451 ]. For example, by coupling of mixtures of 5,5 -[2,2 ]bithiophene and cyclopenta[2,l-fo 3,4- ]-dithiophene (electron-donating units) and 2,1,3-benzothiadiazole... 

S. Barlow, S. A. Odom, K. Lancaster, Y. A. Getmanenko, R. Mason, V. Coropceanu, J.-L. Bredas, S. R. Marder, Electronic and Optical Properties of 4 H-Cyclopenta[2,l-fo 3,4-fo ]Bithiophene Derivatives and Their 4-Heteroatom-Substituted Analogues A Joint Theoretical and Experimental ComparisonL /. Phys. Chem. B 2010,114,14397-14407. 

A couple of studies of copolymers of bridged bithiophenes and EDOT have also been reported, starting with the random copolymer 87 reported by Huang and Pickup [132] in 1998 (Chart 12.12). Copolymer 87 was prepared by electropolymerization of 4 1 mixtures of 4-dicyanomethylene-4ff-cyclopenta[2,l-b 3,4-b j dithiophene and EDOT to give films with conductivities of 0.052—0.69 S cm ... 

S. Rizzo, F. Sannicolo, T. Benincori, G. Schiavon, S. Zecchin and G. Zotti, Calix[4]arene-functionalized poly-cyclopenta[2,l-fc 3,4-fc ]bithiophenes with good recognition abihty and selectivity for small organic molecules for application in QCM-based sensors, J. Mater. Chem., 14, 1804-1811 (2000). 

Poly 5-(cyano-nonafluorobutylsulfonyl)cyclopenta[2,1 -b 3,4-b ]bithiophene has been prepared electrochemically forming a p- and -doping material for electrochromic devices. In a model device incorporated this polymer as both the anode and the cathode electrochromic behavior is demonstrated [190]. 

The first example of a narrow band-gap polymer is polyisothianaphthene [Structure (8)] with a band gap of near 1.0 eV [74,75]. Other polymers designed and synthesized with the intention of developing narrow band-gap polymers include poly(dithieno[3,4-b 3, 4 -d]thiophene [76], poly-4//-cy clopenta[2,1 -6 3,4-/ ]dithiophen-4-one [77], poly-4-dicyanimethy lene-4//-cyclopenta[2,l-6 3,4-6 ]dithiophene [78], poly(2,3-dihexylthieno[3,4-6]-pyrazine (9) [79], polysquaraines [80], polycroconaines [80], poly-(naphtho[2,3-c]thiophene-fl//-bithiophene) (10) [81], a polymer containing... 

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