Novel thiophenes and method for polymerization of said thiophenes

The invention relates to novel thiophenes of formula (I) wherein R and R' are independently - hydrogen, alkyl or alkoxy or together a -O-(CH2)n-O bridge wherein n = 1 to 5. Said thiophenes are suitable for the production of polythiophenes which can be used as organic conductors

Coplanarity by hydrogen bonding in well-defined oligoheterocycles

(Hetero)aryl-aryl coupling for covalent bonding and intramol. hydrogen bond formation for establishing the secondary structure have been united to design and construct well-defined, functionalized macromols. The suitability of azaheterocyclic units to realize this concept is exemplified by star shaped discotic liq. cryst. compds. and ladder-type conjugated copolymers. A review with >40 ref

Band-bap engineering of donor-acceptor substituted pi-conjugated polymers

Three series of alternating donor-acceptor-substituted co-oligomers (with different chain lengths) have been prepd. by application of the Pd-catalyzed Stille coupling methodol. They contain pyrrole or thiophene as the electron-rich unit and quinoxaline or 2,1,3-benzothiadiazole as the electron-deficient unit. The trimethylstannyl group is always located on the electron-rich unit, whereas the bromo substituent is always located on the electron-deficient one. The tBoc-protecting group is used in the synthesis of the pyrrole-contg. oligomers. The incremental bathochromic shift of lmax upon chain elongation of the three series of oligomers is less than that of the homo-oligomers of thiophene and pyrrole; this decrease is caused by a diminished dispersion of the LUMO level upon chain elongation. This conclusion was drawn after comparing the oxidn. and redn. behavior of the thiophene/benzothiadiazole co-oligomers with that of thiophene oligomers. The incremental bathochromic shift is similar for all three series of oligomers and is used as a tool in the band-gap engineering of donor-acceptor-substituted p-conjugated polymer

Band-gap engineering of donor-acceptor conjugated polymers

Three series of alternating donor-acceptor substituted co-oligomers (with different chain length), consisting of pyrrole or thiophene as the electron-rich unit and quinoxaline or 2,1,3,-benzobisthiadiazoles as the electron-deficient unit, were prepd. by Pd-catalyzed Stille coupling methodol. The incremental bathochromic shift of the absorption max. upon chain elongation of the three series of oligomers is less than that of the homo-oligomers of thiophene and pyrrole, which is caused by a diminished dispersion of the LUMO level upon chain elongation. The latter conclusion was drawn after comparing the oxidn.- and redn. behavior of the thiophene/benzothiadiazole oligomers with that of thiophene oligomers. The incremental bathochromic shift shows similarity for all three series of oligomers, which is used as a tool in the band-gap engineering of donor-acceptor substituted conjugated polymer

Alternating copolymer of pyrrole and 2,1,3-benzothiadiazole

The alternating copolymer of pyrrole and 2,1,3-benzothiadiazole is synthesized together with a set of corresponding oligomers, yielding hydrogen bonded ladder structures with push-pull character and an absorption band up to lmax 700 n

Developments in the chemistry and band gap engineering of donor-acceptor substituted conjugated polymers

This paper reviews the tools to manipulate and minimize the band gap of conjugated (co)polymers. The effects of minimization of the bond length alternation and of the incorporation of donor-K-acceptor units are discussed in particular. A systematic study of a series of alternating donor-acceptor oligomers has revealed the achievable limits and allowed for a prognosis of the performance of corresponding copolymers. The decisive influence of the LUMO eigenvectors of the accepters on the band gap is highlighted. A new synthesis of benzo[1,2-c:4,5-c]bis[1,2,5]thiadiazole containing donor-acceptor monomers and their acid-catalyzed polymerization are described. Finally, band gap tuning by appropriate substitution, conformational adjustment and mesoscopic ordering is discussed. (C) 2001 Elsevier Science B.V. All rights reserve