Carbazole-Embedded Pentaphyrin and Hexaphyrin-Like Macrocycles with Panchromatic Absorption Capabilities

The synthesis of a new class of mono- and bis-carbazole-embedded di-p-benzi porphyrinoids via acid-catalyzed condensation is reported. The resulting pentaphyrin and hexaphyrin-like systems exhibit nonaromatic character as supported by AICD and NICS calculations. X-ray crystal structure revealed significant nonplanarity, with macrocycle 1 showing tilted phenylene units. Upon protonation, both macrocycles show sharp color changes, where 2·2H+ displays intense panchromatic absorption ∼800 nm, resulting in a deep black color.