Cyclopentadithiophene

A DFT calculation at the B3LYP level on a 4-substituted cyclopentadithiophene 16 predicted adsorption maxima 1 eV larger than experimental values <2002PGB9221>. 

In the great majority of examples, mass spectral data have been used only to establish the molecular ions or for elemental analysis. Extended cyclopentadithiophene, benzobisoxazole, and benzobisthiazole systems have been shown to exhibit doubly charged parent ions <2002OL4535, 2003MM2705, 2003MM4699>. 

The methylene protons in cyclopentadithiophenes absorb at 5 = 6.36-6.52 ppm <1996CHEC-II(7)841>, and subsequent studies have shown that the methylene protons in 4-substituted cyclopentadithiophenes absorb at slightly higher b values <1999SM(102)1000, 2002OL4535>. In a-substituted benzo[2,T7 3,4-7 ]dithiophene-4,5-diones 28, the methylene protons absorb around b = 7.32-7.68 ppm <2003SM(135)85>. 

The copolymer 614, obtained between cyclopentadithiophene and ben-zothiadiazole, has been reported (07JA3472). 

Oxidative ring closure. Wynberg and co-workers8-9 at the University of Groningen synthesized all six of the cyclopentadithiophenes, that is, analogs of fluorene (m.p. 116-117°) in which both benzene rings arc replaced by thiophene rings. The synthesis of one of the six isomers (4) is summarized as follows. 3,3 -Dithienyl-... 

Coppo, P. and Turner, M.L., Cyclopentadithiophene based electroactive materials, J. 

Cyclopentadithiophenes. 3,4 -Dibromo-2,3 -dithienylmethane treated at -70° with n-butyllithium in abs. ether, the resulting soln. of the dilithio compound cooled and added dropwise under dry Ng during 0.5 hr. to a vigorously stirred ice-cooled suspension of anhydrous CuClg in abs. ether, stirring continued 6hrs. at 0° 7H-cyclopenta[l,2-b 3,4-c ]dithiophene. Y 46%. F. e. s. A. Kraak et al., Tetrahedron 24, 3381 (1968). 

The effect of bridging atoms and side chains on the structure and crystallinity of cyclopentadithiophene—henzothiadiazole polymers was studied (14CM1226). These workers demonstrated that hy combining quantum chemistry, molecular modeling, and scattering data, the effect of subtle chemical changes such as heteroatom substitution on polymer structure and properties, could be demonstrated. 

Bakhshi, A.K., Deepika, and J. Ladrk. 1997. Ah initio study of the electronic structures of polycyclopentadithiophene-4-one and polydicyanomethylene-cyclopentadithiophene Two conjugated polymers with small band gaps. Solid State Commun 101 347. 

Another example of the strategy of donor-acceptor copolymers uses monomers containing an electron-rich moiety like EDOT associated with an electron-poor one like 4H-cydopenta-[l,2-h 3,4-1/] dithiophen-4-one [224] or 4-dicyanomethylene-4H-[l,2-l> 3,4-l/]cyclopentadithiophene (CDM) [225]... 

Jenekhe, Watson, and coworkers [277] reported synthesizing three new donor-acceptor conjugated polymers incorporating thieno[3,4-c]pyrrole-4,6-dione acceptor and dialkoxybithiophene or cyclopentadithiophene donor units. The thieno[3,4-c]pyrrole-4,6-dione acceptor containing materials were studied in bulk heterojunction solar cells and organic field-effect transistors. The polymers had... 

Synthesis oxidative electropolymerization of the respective cyclopentadithiophene monomers via the coupling of the thiophene units [716],... 

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