Benzo dithiophene-4,8-diones

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>. 

An intramolecular Friedel-Crafts approach has also been employed to synthesize l,3,5,7-tetramethyl-4,8-dihydro-benzo[l,2-f 4,5-f ]dithiophene-4,8-dione <20030L1883>. 

A similar mercaptoacetate addition reaction to 5-acyl-4,7-dioxo-4,7-dihydrobenzo[i]thiophene-2-carboxylates followed by cyclization and oxidation to give benzo[ 1,2-6 5,4-ft ]dithiophene-4,8-dione derivatives 29 has been shown <03H1689>. Nitrogen bridged heterocycles, 3-(benzylthio)thieno[3,4-6]indolizine derivatives 30 have been synthesized and intramolecular arene-arene interactions within these compounds were reported <03CPB75>. The arene-arene interaction leads to significant shifts in the proton NMR signals and red shifts in the absorption maxima. 

PBDTP-DPP polvi2,6 -4,8-di(5-ethylhexylthienyl) benzo[l,2-b 3,4-b] dithiophene-alt-5-dibu-tyloctyl-3,6-bis(5-bromo-thiophen-2-yl)pyrrolo[3,4-c] pyrrole-1,4-dione -5.35 -3.56 1.46 6.2 8.5 [75]... 

With a suitable HOMO level, good charge transport and versatility in further functionalization, benzo[l,2- 4,5- ]dithiophene (BnDT) has emerged to be the most popular donor unit to construct the D-A copolymers used in solar cells. Many BnDT derivatives and related polymers have been synthesized and carefully studied. Generally, the synthesis of BnDT-based monomers starts with the preparation of benzo[l,2- 4,5-A ]dithiophene-4,8-dione, which... 

Two high boiling point solvents, i.e., 1-chloronaphthalene and 1,8-diiodooctane, cf. Figure 2.41, were utilized as co-additives in o-dichlorobenzene and chlorobenzene solutions for fine tuning of the donor and acceptor domains in the bulk heterojunction of poly(benzo [ 1,2-b 4,5-b ] dithiophene-i /t-thieno [3,4-c]pyrrole-4,6-dione) and fullerene derivatives (135). 

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