Acetylene and trans-ethylene bridged BIII-subporphyrin dimers were synthesized by cross-coupling reactions of meso-bromo BIII subporphyrin. These dimers display perturbed and red-shifted absorption spectra reaching around 750 nm and fluorescence reaching at around 850 nm with high quantum yields of 0.39 and 0.47, respectively. DFT calculations have revealed that the HOMOs and the LUMOs of both dimers are spread over the two subporphyrin units as an indication of effective conjugation between the two subporphyrin units. The large Stokes shifts and characteristic pico-second time-resolved transient absorption spectra indicated that the S1-states of the dimers relax with structural changes, which are larger for the trans-ethylene bridged dimer.
All Science Journal Classification (ASJC) codes
- Organic Chemistry