magnified imageTwo highly soluble donor‐σ‐acceptor and donor‐σ‐accepter‐σ‐donor type fluorescence switches consisting tetrathiafulvalene (TTF) and 3,4,9,10‐perylene tetracarboxylic diimides (PDI) were synthesized. The structure of the dyad and triad as well as their intermediates was characterized by 1H NMR, 13C NMR MS, elemental analysis. Their fluorescence behavior could be modulated by oxidization and reduction of the TTF unit using either chemical or electrochemical method. J. Heterocyclic Chem., (2009).

in Wiley Online Library (wileyonlinelibrary.com).Silole-core phenylacetylene dendrimers were designed and synthesized, among them, the model compound (n ¼ 0) and the first generation of the dendrimer (n ¼ 1) were obtained by the reaction of 2,5-dibromosilole with corresponding terminal alkynes, the second generation of the dendrimers (n ¼ 2) was synthesized from 2,5-diiodosilole. These compounds indicated the absorptions of both phenylacetylene dendrons (250-350 nm) and silole core (400-500 nm). The first generation displayed efficient energy transfer from phenylacetylene dendrons to silole core, whose energy transfer efficiency was as high as 80%. These compounds were used as chemical sensors to probe explosive, for picric acid (PA), the Stern-Volmer constants of model compound and the first generation are 7120 and 5490M À1 , respectively.

Phenylacetylene dendrimers 9-11 containing fluorene as the core with a larger HOMO-LUMO energy gap were synthesized and characterized. Their structure and properties were studied by UV, FL, 1 H NMR, MS etc. These novel phenylacetylene dendrimers exhibit unique photophysical properties. They exist a new absorption band around 340 nm whose molar coefficient decreases with increasing generation. The band-gaps of 9-11 are 3.54, 3.43 and 3.02 respectively. The fluorescence quantum yield of 10 is as high as 0.61.

Novel porphyrin-perylene diimide dyad (TPP-PDI) and porphyrin-perylene diimide-porphyrin triad (TPP-PDI-TPP) were synthesized and characterized. Their structure and properties were studied by UV, FL, 1 H NMR, MS, elemental analysis, etc. The variation of fluorescence feature and UV spectra of TPP-PDI-TPP triad were investigated at different concentration of CF 3 COOH in THF. The incorporation of CF 3 COOH leads to the closure of the efficient charge transfer decay. After protonation of porphyrin units, the fluorescence intensity of TPP-PDI-TPP triad increased greatly. The fluorescence intensity of TPP-PDI-TPP triad restored after addition of triethylamine into the solution. Thus, TPP-PDI-TPP triad was a proton-type fluorescence switch based on acid-base control. Moreover, different from porphyrin-perylene type molecular switches reported before, this TPP-PDI-TPP triad has wonderful solubility in organic solvents.