Planar hexaphyrin-like macrocycles turning into bis-BODIPYs with box-shaped structures exhibiting excitonic coupling

Planar carbazole based hexaphyrin-like macrocycles with bis-coordinating cores and box-shaped cyclic BODIPYs were synthesized. Solution and solid-state structure analysis of the free macrocycles indicates an inversion of two pyrrole rings, resulting in a two-dipyrrin-like environment. The BF 2 complexes show large Stokes shifts and exhibit excitonic coupling, fine-tuned by the meso -substituents. This present study reveals the synthesis and excited-state dynamics of carbazole embedded hexaphyrin-like macrocycles and their bis-BODIPY complexes. Time-resolved spectroscopy was performed to elucidate the excitonic coupling in conjunction with electronic structure calculations.