Synthesis of Phlorin Analogues of Dithiacorrphycene and Their Use as Specific Chemodosimetric Sensors for Fe Ions.

The first examples of stable phlorin analogues of dithiacorrphycene were synthesized by treating appropriate tetrapyrranes with two equivalents of trifluoroacetic acid in CH Cl followed by oxidation with p-chloranil. The oxidative coupling of tetrapyrrane resulted in the formation of two unexpected phlorin analogues of dithiacorrphycenes that differed from each other at the meso-sp -carbon, and the two macrocycles were easily separated and isolated by column chromatography. The novel macrocycles were confirmed by X-ray crystallography and characterized by HRMS, 1D and 2D NMR spectroscopy, absorption spectroscopy, cyclic voltammetry, and time-dependent DFT studies. X-ray structure analysis revealed the highly strained and distorted nature of the macrocycles. The macrocycles showed one ill-defined absorption band at λ≈315 nm and a broad band at λ≈530 nm. Because both macrocycles possess two thiophene and two pyrrole rings with one ionizable inner NH, the cation-sensing properties of the phlorin analogues of dithiacorrphycenes have been investigated. The phlorin analogues of dithiacorrphycenes act as specific chemodosimetric sensors for Fe ions by converting phlorin analogues of dithiacorrphycenes into dithiacorrphycene.