Synthesis of direct ß-to-ß linked porphyrin arrays with large electronic interactions: branched and cyclic oligomers.

ABSTRACT

Direct ß-to-ß linked branched and cyclic porphyrin trimers and pentamers have been synthesized by the Suzuki-Miyaura coupling of ß-borylporphyrins and ß-bromoporphyrins. The cyclic porphyrin trimer, the smallest directly linked cyclic porphyrin wheel to date, and its twined pentamer, exhibit small electrochemical HOMO-LUMO gaps, broad nonsplit Soret bands, and red-shifted Q-bands, thus indicating large electronic interactions between the constituent porphyrin units.