Synthesis and studies of m/p-phenylene bridged bis(3-Pyrrolyl BODIPY)s

The first examples of m-/p-phenylene bridged bis(3-pyrrolyl BODIPY)s were synthesized by oxidizing the readily available m-/p-phenylene bridged bis(dipyrromethane) with DDQ in CH3CN followed by treatment with excess pyrrole and complexation with BF3?OEt2 in the presence of triethylamine. To the best of our knowledge, no straightforward synthetic method is available to prepare m-/p-phenylene bridged bis(3-pyrrolyl BODIPY)s. The bis(3-pyrrolyl BODIPY)s can be used as novel ligands for metal coordination chemistry by demasking BF2 units from bis(3-pyrrolyl BODIPY)s in the presence of Lewis acids. The bis(3-pyrrolyl BODIPY)s absorb at -585 nm with enhanced molar absorptivity compared to the monomer, 3-pyrrolyl BODIPY. The m-phenylene bridged bis (3-pyrrolyl BODIPY) emits strongly at -600 nm with a quantum yield of 0.34 whereas p-phenylene bridged bis (3-pyrrolyl BODIPY) emits relatively weakly in the same region with a quantum yield of 0.21. The electrochemical studies revealed that the two 3-pyrrolyl BODIPY units in bis(3-pyrrolyl BODIPY) dyads did not interact with each other. DFT/TD-DFT studies were used to understand the structure and electronic properties of bis(3pyrrolyl BODIPY)s.

Automated summary

The first examples of m-/p-phenylene bridged bis(3-pyrrolyl BODIPY)s were synthesized and can be used as novel ligands for metal coordination chemistry. They have enhanced molar absorptivity compared to the monomer, 3-pyrrolyl BODIPY. The m-phenylene bridged bis (3-pyrrolyl BODIPY) emits strongly at -600 nm with a quantum yield of 0.34 whereas p-phenylene bridged bis (3-pyrrolyl BODIPY) emits relatively weakly in the same region with a quantum yield of 0.21.