pi-Conjugated twin molecules based on truxene: synthesis and optical properties.

[structure: see text] A series of novel extended pi-conjugated twin molecules based on 10,15-dihydro-5H-diindeno[1,2-alpha;1',2'-c]fluorene (truxene) have been prepared via Pd(0)-catalyzed Suzuki coupling, Sonogashira coupling, and McMurry reactions, respectively. 9,9'-Spirobifluorenylene, ethynylene, and vinylene groups as the bridge are introduced to connect both truxene moieties to understand the effect of the large steric chromophores on the properties of the desired materials. The investigation of optical properties of TM1-3 by UV-vis and photoluminescent spectroscopy demonstrates that the optical properties of the twin molecules are strongly affected by the pi-linkages.