Phthalorubines: Fused‐Ring Compounds Synthesized from Phthalonitrile

A series of dibenzo[a,f][1,3,5]triazino[2,1,6‐cd] pyrrolizine compounds have been synthesized from phthalonitriles by a facile intramolecular cyclization process using “half‐phthalocyanine” precursors, and they were characterized by X‐ray crystallography, 1H NMR spectroscopy, UV/Vis, and theoretical calculations. These compounds have spectroscopic profiles similar to phthalocyanines and porphyrins, although their inner‐core structures and coordination types are totally different. They can be regarded as a new class of aromatic fused‐ring compounds. The low‐energy absorption of these new fused‐ring compounds are located at around 600 nm. Such a low‐energy π–π* transition is scarce in aromatic compounds having a similar molecular size. According to the nomenclature of phthalocyanines, these types of compounds have been named phthalorubines (Prs). Ruby red: A new class of fused‐ring compounds has been synthesized from phthalonitrile. These compounds have very similar spectroscopic profiles as phthalocyanines, but have a very different inner‐core structure and coordination properties. According to the nomenclature of phthalocyanines, these compounds have been named as phthalorubines (Prs).