1,2-Phenylene-Incorporated Smallest Expanded Calix[4]pyrrole via One-Step Synthesis of Tetrapyrrane: A Fluorescent Host for Fluoride Ion

Synthesis of tetrapyrrane 8 from acetone and pyrrole via one-step condensation was achieved for the first time along with a much-improved yield of the tripyrrane 9. Diborylation of the tetrapyrrane and subsequent 1 + 1 cyclocoupling with 1,2-diiodobenzene following the Suzuki protocol generated novel o-phenylene incorporated macrocycle belonging to the smallest mesoexpanded calix[4]pyrrole family. The latter macrocycle displays exclusive turn-on fluorescence sensing of fluoride ion upon complexation via a unique partial cone conformation supported by DFT analysis in acetonitrile solvent.

Automated summary

The synthesis of tetrapyrrane 8 from acetone and pyrrole via one-step condensation was achieved for the first time, along with an improved yield of tripyrrane 9. The diborylation of tetrapyrrane and subsequent 1 + 1 cyclocoupling with 1,2-diiodobenzene following the Suzuki protocol led to the generation of a novel o-phenylene incorporated macrocycle. This macrocycle displayed exclusive turn-on fluorescence sensing of fluoride ion through a unique partial cone conformation supported by DFT analysis in acetonitrile solvent.