Oligothiophenes helical

UV-Vis absorption studies revealed that the helical oligothiophenes 44 and 45 had identical absorption onset but significantly red shifted to the onset for the planar trithiophene 42. This provided an estimate for the optical band gap,... 

A. Rajca, M. Miyasaka, M. Pink, H. Wang, S. Rajca, Helically Annelated and Cross-conjugated Oligothiophenes Asymmetric Synthesis, Resolution and Characterization of a Carbon-Sulfur [7]Helicene, J. Am. Chem. Soc. 2004, 126, 15211-15222. 

Tetraphenylenes and helical p-oligothiophenes as annulated, chiral 7t-con-jugated systems 07SL1799. 

M. Melncci, G. BarbareUa, M. Gazzano, M. Cavallini, F. Biscarini, A. Bongini, F. Piccinelh, M. Monaii, M. Bandini, A. Umani-Ronchi and P. Biscarini, Synthesis, multiphase characterization and helicity control in chiral DACH-linked oligothiophenes, Chem. Eur. J., 12, 7304-7312 (2006). 

Another recent article was published by Takata and co-workers. The polymer was composed of oligothiophene monomers (pink) as a planarity-switchable spacer and a C2-chiral spirobifluorene monomer (green). Under redox conditions, the polymer switched from a one-handed helical shape to a coil-shaped rigid helical foldamer (Figure 5.25). 

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