Invited feature articleSynthesis of porphyrin dendrimers via Heck reaction and their photovoltaic properties

- Synthesis of dendrimers first and second generation linear and ramified dendrimers with porphyrin as nucleus and OPV in the dendritic branches.
- High conjugated porphyrin dendrimers in one pot reaction were obtained.
- With the appropriate substituent is possible to use them as a block system to obtain a great variety of π-conjugated macromolecules.
- The trans configuration of the OPV systems by 1H NMR spectroscopy was observed; this also by X-ray studies was demonstrated.
- The length and configuration of the π-conjugated system have a great influence in the electronic response.

Porphyrins meso-substituted with p-phenylene vinylene (OPV) were synthesized. The porphyrin dendrimers obtained showed a strong dependence on the type of connection of the dendritic branches. In the instance of the all trans-conformation linkages, an H-type aggregate is obtained for the linear OPV and strong J-aggregate for the ramified OPV. An adequate intramolecular energy transference stemming from the OPVs (donors) to the respective cores was observed. Furthermore, the number oligo(p-phenylene vinylene) (OPV) groups linked to the porphyrin system increase the energy transfer efficiency. This behavior also was observed in the photovoltaic studies.

High conjugated meso-subtituted porphyrins with linear and ramified OPV groups via Heck reaction were synthesized. The optical studies showed the formation of intermolecular aggregates type J for the dendrimers with linear and for the ramified OPV groups.75