Synthesis and Characterization of Star-Shaped Donor-Acceptor-Donor Structures.

A Sonogashira coupling reaction led to star-shaped 1,3,5-tris({5-[7-(thiophen-2-yl)benzo[ c][1,2,5]thiadiazol-4-yl]thiophen-2-yl}ethynyl)benzene derivatives. The star-shaped molecules were optically analyzed, and - depending on their substitution pattern - they displayed bathochromically shifted absorptions, which were compared to their nonlinked arm precursors. The materials displayed a highly interesting morphology in bulk when blended with [6,6]-phenyl-C61-butyric acid methyl ester (PCBM). One derivative formed columnar structures and revealed prospective use in photodiodes. [ABSTRACT FROM AUTHOR]