Tobe Laboratory Mariko Ohno

1. Structure-Property Relationships of Donor/Acceptor-Functionalized Tetrakis(phenylethynyl)benzenes and Bis(dehydrobenzoannuleno)benzenesMichael M. Haley et al.,J. Am. Chem. Soc. 2005,127, 2464 Tobe Laboratory Mariko Ohno

2. Conjugated pathways present in the TPEB and DBA systems ・ linear-conjugated (path a) ・ cross-conjugated (path b) ・ "bent" conjugated (path c)

3. TPEBs and BisDBAs tetrakis(phenylethynyl)benzene bis(dehydrobenzo[14]annuleno)benzene bis(dehydrobenzo[15]annuleno)benzene

4. 1,2,4,5-tetrakis(phenylethynyl)benzenes （TPEBs）

5. Bis(dehydrobenzoannuleno)benzenes (BisDBAs)

6. 1H NMR Spectra of Bis[14]-and[15]DBAs Bis[15] DBA13 δ= 8.42 ppm Bis[14] DBA14 δ= 8.24 ppm

7. UV-vis spectra of TPEBs

8. UV-vis spectra of TPEBs and DBAs

9. UV-vis spectra of Donor/Acceptor TPEBs and DBAs

10. Protonation/deprotonation of TPEB 2

11. Fluorescence emission of selected TPEBs and DBAs

12. Emission consequences of protonation of DBA 13

13. The aggregation Aggregate sizses of dimers 15, 16, 18, 19 17 Aggregates much larger than dimer Concentration-dependent chemical shifts chemical shifts of the aromatic protons of DBA 15 in CD2Cl2 at 20 ℃ The upfield shifts of the protons

14. Polymerization of DBA 17 in CDCl3 observed by 1H NMR

15. Summary • The authors noticed an enhancement of the optical activity transitioning from neutral to tetra-donor to donor/acceptor systems as seen by large red shifts of the UV-vis λmax and the development of strong charge-transfer bands. • The tetra-donor compounds provided the best efficiency for fluorescence. • In both absorbance and emission, protonation of the donor groups quenched or altered the optical enhancements. • Self-association properties for the donor/acceptor DBAs to form dimers in solution were observed. • An interesting ordered polymerization triggered by self-association was observed for only one isomer (17) in only CDCl3, suggesting that the reaction is very sensitive to geometrical and solvent effects.