Ring‐Opened Hemiporphyrazines: Helical Molecules Exhibiting Circularly Polarized Luminescence

We designed and synthesized a new type of small helical molecule exhibiting intense circularly polarized luminescence (CPL) (12H) by modifying a 20π‐electron hemiporphyrazine with a large transition magnetic dipole moment. The hemiporphyrazine ring was opened and one additional pyridine unit was introduced, resulting in an overlap of two pyridine rings. X‐ray structure analysis confirmed that 12H and its zinc complex (1Zn) adopt a helical geometry. A racemic mixture of 1Zn was resolved into two enantiomers ((P)‐ and (M)‐1Zn), which exhibited CPL with a high luminescence dissymmetry factor (glum) value of ±2.1×10−2. The origin of the large glum value was rationalized by means of DFT calculations. Helical structures could be formed in a diastereoselective manner by covalently attaching chiral units to the skeleton (1’2H and 1’Zn). 1Zn was found to possess chiral recognition ability for amines. Ring to helix: The large transition magnetic dipole moment of the 20π‐electron ring system was used to design and synthesize a ring‐opened π‐conjugated system as CPL‐active helical organic molecules (see figure).